ncsu physics demonstrations manualdemoroom.physics.ncsu.edu/pdf/demo_man.pdf · ncsu physics...

NCSU Physics Demonstrations Manual

Keith WarrenSr. Lecturer

[email protected]

July 20, 2017

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Contents

Mechanics 11A MEASUREMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1A10 Basic Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11A30 Coordinate Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21A40 Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21A60 Scalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1C MOTION IN ONE DIMENSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C10 Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C20 Uniform Acceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C30 Measuring g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1D MOTION IN TWO DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51D15 Velocity, Position, and Acceler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51D40 Motion of the Center of Mass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51D50 Central Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61D52 Deformation by Central Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71D55 Centrifugal Escape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71D60 Projectile Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1E RELATIVE MOTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81E10 Moving Reference Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1F NEWTON’S FIRST LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91F10 Measuring Inertia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91F20 Inertia of Rest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1G NEWTON’S SECOND LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111G10 Force, Mass, and Acceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111G20 Accelerated Reference Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1H NEWTON’S THIRD LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131H10 Action and Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131H11 Recoil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1J STATICS OF RIGID BODIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131J10 Finding Center of Gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131J11 Exceeding Center of Gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141J20 Stable, Unstab., and Neut. Equi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151J30 Resolution of Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161J40 Static Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1K APPLICATIONS OF NEWTON’S LAWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181K10 Dynamic Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181K20 Friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181K30 Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

1L GRAVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191L20 Orbits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

1M WORK AND ENERGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201M10 Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201M20 Simple Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201M40 Conservation of Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1N LINEAR MOMENTUM AND COLLISIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221N10 Impulse and Thrust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221N20 Conservation of Linear Momentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221N22 Rockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221N30 Collisions in One Dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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1Q ROTATIONAL DYNAMICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241Q10 Moment of Inertia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241Q20 Rotational Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251Q30 Transfer of Angular Momentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261Q40 Conservation of Angular Momentu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261Q50 Gyros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281Q60 Rotational Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1R PROPERTIES OF MATTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301R10 Hooke’s Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301R20 Tensile and Compressive Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301R30 Shear Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301R40 Coefficient of Restitution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311R50 Crystal Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Fluid Mechanics 322A SURFACE TENSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2A10 Force of Surface Tension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322A20 Capillary Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2B STATICS OF FLUIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322B20 Static Presssure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322B30 Atmospheric Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332B40 Density and Buoyancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2C DYNAMICS OF FLUIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362C10 Flow Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362C20 Bernoulli Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362C30 Viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372C50 Vorticies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Waves and Oscillations 383A OSCILLATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3A10 Pendula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383A15 Physical Pendula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403A20 Springs & Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403A40 Simple Harmonic Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403A50 Damped Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413A60 Driven Mechanical Resonance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413A70 Coupled Oscillations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413A80 Lissajous Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423A95 Non-Linear Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

3B WAVE MOTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433B10 Transverse Pulses and Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433B20 Longitudinal Pulses and Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443B22 Standing Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453B25 Impedence and Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463B27 Compound Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463B30 Wave Properties of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463B40 Doppler Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473B50 Interference and Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473B55 Inter. and Diff. of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483B60 Beats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483B70 Coupled Resonators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

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3C ACOUSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493C10 The Ear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493C20 Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503C30 Intensity and Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503C50 Wave Analysis and Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503C55 Music Perception and the Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3D INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513D20 Resonance in Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513D30 Resonance Cavities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513D32 Air Column Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513D40 Resonance in Plates, Bars, Soli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523D46 Tuning Forks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Thermodynamics 534A THERMAL PROPERTIES OF MATTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4A10 Thermometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534A30 Solid Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544A40 Properties of Materials at Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4B HEAT AND THE FIRST LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564B10 Heat Capacity and Specific Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564B20 Convection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564B30 Conduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564B50 Heat Transfer Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574B60 Mechanical Equivalent of Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574B70 Adiabatic Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

4C CHANGE OF STATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594C20 Phase Changes: Liquid-Solid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594C30 Phase Changes: Liquid-Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594C31 Cooling by Evaporation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594C33 Vapor Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604C40 Sublimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604C50 Critical Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

4D KINETIC THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604D20 Mean Free Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604D30 Kinetic Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

4E GAS LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614E10 Constant Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614E20 Constant Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614E30 Constant Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

4F ENTROPY AND THE SECOND LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624F10 Entropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624F30 Heat Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Electricity and Magnetism 635A ELECTROSTATICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5A10 Producing Static Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635A20 Coulomb’s Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645A40 Induced Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645A50 Electrostatic Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

5B ELECTRIC FIELDS AND POTENTIAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665B10 Electric Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

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5B20 Gauss’ Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685B30 Electrostatic Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5C CAPACITANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695C10 Capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695C20 Dielectric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695C30 Energy Stored in a Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

5D RESISTANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705D10 Resistance Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705D20 Resistivity and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705D40 Conduction in Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5E ELECTROMOTIVE FORCE AND CURRENT . . . . . . . . . . . . . . . . . . . . . . . . . . . 715E40 Cells and Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715E60 Piezoelectricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5F DC CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715F20 Circuit Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715F30 RC Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

5G MAGNETIC MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725G10 Magnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725G20 Magnet Domains & Magnetization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725G30 Paramagnetism and Diamagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735G50 Temperature and Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5H MAGNETIC FIELDS AND FORCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745H10 Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745H15 Fields and Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765H20 Forces on Magnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775H25 Magnet/Electromagnet Interact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775H30 Force on Moving Charges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785H40 Force on Current in Wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785H50 Torques on Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

5J INDUCTANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795J10 Self Inductance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

5K ELECTROMAGNETIC INDUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795K10 Induced Currents and Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795K20 Eddy Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805K30 Transformers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 815K40 Motors and Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

5L AC CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 835L20 LCR Circuits - AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 835L30 Filters and Rectifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

5N ELECTROMAGNETIC RADIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845N10 Transmission Lines and Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845N20 Tesla Coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845N30 Electromagnetic Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Optics 856A GEOMETRICAL OPTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6A10 Reflection From Flat Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 856A20 Reflection from Curved Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 866A40 Refractive Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 876A42 Refraction at Flat Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 886A44 Total Internal Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

v

6A46 Rainbow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906A60 Thin Lens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906A65 Thick Lens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

6B PHOTOMETRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916B40 Blackbodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

6C DIFFRACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926C10 Diffraction Through One Slit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926C20 Diffraction Around Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

6D INTERFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 936D10 Interference From Two Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 936D20 Gratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 936D30 Thin Films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

6F COLOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956F10 Synthesis and Analysis of Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956F30 Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 966F40 Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

6H POLARIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 966H10 Dichroic Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 966H20 Polarization by Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976H30 Circular Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976H35 Birefringence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

6J THE EYE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 986J11 Physiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

6Q MODERN OPTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 986Q10 Holography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Modern Physics 987A QUANTUM EFFECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

7A10 Photoelectric Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 987A50 Wave Mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7B ATOMIC PHYSICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 997B10 Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 997B11 Absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1007B13 Resonsance Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1007B35 Electron Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7D NUCLEAR PHYSICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1017D10 Radioactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

7F RELATIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1017F10 Special Relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Astronomy 1018A PLANETARY ASTRONOMY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

8A10 Solar system Mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1018A20 Planetary Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

8B STELLAR ASTRONOMY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1028B10 Misc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

8C COSMOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1038C10 Models of the Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

vi

Equipment 103

9A BLACKBOARD TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9A10 Blackboard Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9A20 Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9A30 Slide Projectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9A34 Film Projectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9A36 Overhead Projectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9A38 Video & Computer Projection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9A40 Photography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9A73 Unclassified Demonstrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9B ELECTRONIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9B10 Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9B60 Light Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9C MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9C10 Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9C20 Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9C40 Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

vii

1

Mechanics

1A MEASUREMENT

1A10 Basic Units

Basic Unit Set - VEPD 01-01 - 1A10.10 Laser Disc or DVD - Video Encyclopedia of PhysicsDemonstrations Disc 01-01.Video shows a clock with a second sweep; meter and yard sticks; kilogram and pound mass.

Standards of Mass - 1A10.20 Two brass bars areused to show the difference in mass between thekilogram and the pound at sea level. The two barsare made of the same material to aid in studentunderstanding. The difference in mass is easilyseen by the difference in volume.

Standards of Length - 1A10.30 A meter stickand a yard stick are provided to compare. Anice twist to this demonstration is to request aglobe and talk about the original definition of thekilometer: The line from the pole to the equatorthrough Paris was 10,000 kilometers.

Painted Meter Stick - 1A10.35 A standard me-ter stick is painted on the inch side in alternatingyellow and red every 10 centimeters.

Inch Cubes - 1A10.51 Four cubes are suppliedwith cross sections of 1 inch square, 4 inchessquare, 9 inches square and 16 inches square. Thecubes are used to help explain volumes.

Mole Samples - 1A10.65 Show samples of onemole of aluminum, copper, air (wire frame enclos-ing one mole) and water.In the bag, A is Zinc, B is Aluminum, C is Ironand D is Copper.

2 MECHANICS

1A30 Coordinate Systems

Euler Angles - 1A30.21 Two coordinate modelsare provided, each with metal rods for the orthog-onal axes. The models are attached at the originwith a universal joint so that the Euler rotationangles can be demonstrated.

1A40 Vectors

Meter Stick Vectors - 1A40.11 These meterstick vectors can be used to introduce vectors anddemonstrate vector addition and subtraction (see1A40.30)

Vector Components - VEPD 01-04 - 1A40.14 Laser Disc - Video Encyclopedia of PhysicsDemonstrations Disc 01-04Video shows that vectors may be broken down into their components along the coordinate axes forpurposes of mathematical manipulation.

Vector Addition and Subtraction - 1A40.30Use magnetic vectors on the white board to showhead-to-tail or parallelogram addition or subtrac-tion.

Vector Addition (parallelogram) vepd 01-02 - 1A40.31 Laser Disc - Video Encyclopedia ofPhysics Demonstrations Disc 01-02.Video shows an animation of vectors being added using the parallelogram method.

Vector Addition (head to tail) vepd 01-03 - 1A40.33 Laser Disc - Video Encyclopedia ofPhysics Demonstrations Disc 01-03.Video shows an animation of vector addition using the head to tail method.

1A60 Scalling

Powers of Ten - 1A60.10 This VHS film runsabout 10 minutes. “POWERS OF TEN is an ad-venture in magnitudes. Starting at a picnic by thelakeside in Chicago, this famous film transportsyou out to the edges of the universe and in to themicro-world of cells, molecules, and atoms. It isa careful picture of the universe as we currentlyknow it, according to the best available evidenceand scientific explanation.”

1C MOTION IN ONE DIMENSION 3

1C MOTION IN ONE DIMENSION

1C10 Velocity

Truck on Moving Sheet - 1C10.10 Demonstratesuperposition of velocities by pulling on the sheetbelow the moving tractor.

Pasco Dynamics Cart - 1C10.20 A (nearly) fric-tionless PASCO cart is made to move across atrack showing various qualities of velocity.

Air Track and Glider - 1C10.25 An excellentdemonstration for showing constant velocity. Theblower is a little loud, but you can talk over it.See notes!

1C20 Uniform Acceleration

Penny and Feather - 1C20.10 The demo showsthat, when not affected by air resistance, a “light”object (the feather) falls at the same rate as a“heavy” object (the penny).

Drop Lead and Cork Balls - 1C20.15 Thisdemonstration is used to show that the acceler-ation due to gravity does not depend on the massof the object. F = G(Mm)/(r*r) = ma. Solvingthis for acceleration gives: a = GM/(r*r).

4 MECHANICS

Drop Ball and Paper - 1C20.16 This demon-strate the effect of air resistance. The crumpledpaper experiences a smaller force directed upwarddue to air resistance. The class will notice thatthe ball and the crumpled sheet of paper acceler-ate downward at similar rates.

Equal Time Equal Distance Drop - 1C20.20The two strings have weights/washers attached atdifferent increments. When dropping each stringonto a pizza pan a loud clang is heard with eachcollision. The sounds of the objects, more impor-tantly, the time between the sounds will make thepoint of the demonstration

Inclined Airtrack/Pasco Carts - 1C20.30THIS WORKS BETTER WITH PASCO DY-NAMIC CARTS (1C10.20) Air track will be lev-eled. Place aluminum blocks under single leg of airtrack to create desired incline. Sonic ranger canbe used to measure acceleration with the PascoDynamic Carts.

1C30 Measuring g

Catch a Meter Stick - 1C30.55 This demo willquantitatively show the reaction time of the stu-dent volunteer.This demonstration makes use of the followingequation:x = (1/2)g*t2

Catch a Dollar - 1C30.551 This a qualitativeversion of 1C30.55, where the reaction time of thestudent volunteer is tested. See 1C30.55 for moredetails.

1D MOTION IN TWO DIMENSIONS 5

1D MOTION IN TWO DIMENSIONS

1D15 Velocity, Position, and Acceler

Ultrasonic Ranger and Student - 1D15.10This shows, in real time, the position, velocity andacceleration vs. time of a student volunteer mov-ing in from of the motion detector.

High Road/Low Road - 1D15.20 This demon-strates that even though the low path is longer, itsthe way the object’s potential energy is convertedto mechanical energy that “wins the race”.Both balls begin and end at the same height. Oneball travels on a low hilly path and the other ona straight incline. The ball traveling the low pathconverts more of its potential energy to kineticenergy. This gives it enough extra velocity to makeit to the end faster even though it must travelfarther.

Potential-Kinetic Energy Tracks - 1D15.201This demonstration shows that no matter the pro-file of the ramp, the same ball released from thetops of all 4 ramps achieve the same final veloc-ity. The same final velocity is found from the finalresting position of the ball catcher.

1D40 Motion of the Center of Mass

Throwing Board - 1D40.14 This is an object hadan off-center weight mounted inside. The demon-strator throws this board and the class can observethe rotation around its center of mass.

6 MECHANICS

Center of Mass of Non-rigid Object -1D40.141 This object is a collection of randomitems, such as a tennis ball, stick, spring, massand string, connect together. Throw the objectthrough the air to demonstrate that the center ofmass of the entire object follows a parabolic tra-jectory even though individual items in the objectmay not.

1D50 Central Forces

Ball on a String - 1D50.10 This simple demon-stration shows centripetal force as the tension inthe string as the ball is whirled around.

Whirligig - 1D50.20 This demonstration showsthe magnitude of centripetal force is not necessar-ily dependant on the spinning mass but also onother factors like angular velocity and radius oftravel.

Pail of Water/Pail of Nails - 1D50.40 A plat-form holding a vessel of some “fluid” is spun in acircle to show central forces.

1D MOTION IN TWO DIMENSIONS 7

Penny on the Coat Hanger - 1D50.45 This isanother demonstration of central forces. The pailof water/pail of nails is easier to master (see num-ber 1D50.40)

1D52 Deformation by Central Forces

Flattening Earth - 1D52.10 Two metal strips are bent into a circle and mounted on a pole toform a sphere. The tops of the circles are not mounted, but the pole sticks through a hole in eachof them. When the pole is attached to a motor and spun up, the sphere flattens out.

Water Glass Parabola - 1D52.201 Seven plastic wineglasses are mounted to a turntable top.When filled with water and rotated, the water levels move to form a parabola.

1D55 Centrifugal Escape

Falling off the Merry Go Round - 1D55.30This demonstrates that the centripetal force re-quired to hold an object on a rotating disk varieswith radius and speed.Place an object on the rotating disk at differentradii and run the motor at different speeds.

1D60 Projectile Motion

Ball to Throw - 1D60.05 Several balls are avail-able for throwing accross the room to show theparabolic path followed by a trajectory: softball,large Nerf ball, whiffle ball, basketball, tennis balland many more.

Howitzer - 1D60.10 This demonstration shows the independance of hozizontal motion (the cart)and vertical motion (the ball’s path) of a single system.

Howitzer on an Incline - 1D60.15 This demon-stration shows the independance of hozizontal mo-tion (the cart) and vertical motion (the ball’spath) of a single system in a slightly different waythan 1D60.10

8 MECHANICS

Simultaneous Fall - Large - 1D60.20 Thisdemonstration shows the gravity has the same ef-fect on all objects whether they are dropped, orprojected. If both balls start with the same ver-tical velocity, that no matter what the horizontalvelocity, they will land at the same time.

Simultaneous Fall - Small - 1D60.201 This demo operates similar to the large version. The ballsare hard to be seen by students, but the sound of the balls striking the floor can be heard by all.This model is easier to repeat in class.

Monkey and Hunter - 1D60.30 The Monkey and Hunter demonstration is a classic way to showhow gravity affects a projectile. A hunter aims a gun directly at a monkey hanging from a treelimb. The monkey decides to outsmart the hunter by releasing its grip on the tree the instant itsees the flash of the muzzle. The monkey thinks that that gravity will pull it down and the bulletwill fly over its head. However, as we all know, the bullet is accelerated downward by gravity atthe same rate as the monkey and the bullet still hits it. For years the physics department wouldshoot a projectile at a stuffed monkey. Using photogates, the stuffed monkey would be releasedat the moment the projectile left the gun. This was a very dramatic demonstration. A little toodramatic for some. As the story goes, the department received a cease and desist order on behalf ofa certain animal rights group. Apparently shooting a toy monkey is just as bad as shooting a realone. Considering that this is a classic physics demonstration, a substitute for the monkey had tobe found. The university paid a consulting firm several thousand dollars to determine the one thingwe could shoot which would offend absolutely nobody. They found it. The following semester, weintroduced the UNC-CH mascot to the cheers of students everywhere. We have also had successwith a certain blue devil from time to time.

Range of a Gun - 1D60.40 This demonstrationshows two dimensional motion via a projectile. Aquantitative or qualitaive experiment can be donewith this setup.

Parabolic Trajectory - 1D60.60 The pendulashow the path of a projectile whose initial anglecan be adjusted by pivoting the rod. The lengthof each dowel is proportional to the square of thedistance from the pivot point.

1E RELATIVE MOTION 9

1E RELATIVE MOTION

1E10 Moving Reference Frames

Crossing the River - 1E10.10 Demonstrate superposition of 2-D velocities by pulling on the sheetbelow the moving tractor.

Frames of Reference - 1E10.20 This is a classic 1960 film by Professor Patterson Hume andProfessor Donald Ivey of the University of Toronto. The film starts and ends with a Foucaultpendulum. This film is available on videodisc and can be projected to a large screen. Running time:30 minutes

1F NEWTON’S FIRST LAW

1F10 Measuring Inertia

Inertia Balance - 1F10.11 The inertia balanceis designed for use in a laboratory experiment inwhich mass is quantitatively measured indepen-dent of the earth’s gravitational force. This samemethod is used in determining the mass of an ob-ject under weightless conditions in space flights.The apparatus consists of two small platforms con-nected by two horizontal, nonsagging, spring-steelblades. A cylinder with a shoulder on which it canrest in a hole in the platform and a hook by whichit can be suspended are included. This cylindermay be used as an object of unknown mass.

1F20 Inertia of Rest

Inertia Ball - 1F20.10 Depending on the speedthat you move the lower rod downward, the inertiaof the ball will break either the top or the bottomstring.Have your students guess what sort of pull willsnap which string.

Smash Your Hand - 1F20.20 This demonstra-tions shows the inertia of rest.

10 MECHANICS

Hit the Nail on the Head - 1F20.22 This isanother demonstration of the inertia of rest. Thename says it all.

Table Cloth Pull - 1F20.30 A classic demon-stration of the inertia of rest! A quick pull of thetablecloth and everything remains on the table.

Eggs and Pizza Pan - 1F20.35 Another classicdemonstration of the inertia of rest. Coordinationis needed to make sure you don’t end up with eggon you face!Golf balls are the default (eggs are optional -please supply your own).

Pen and Embroidery Hoop - 1F20.36 No mat-ter the pen or bottle used, this demonstration ofthe inertia of rest requires practice and knowledgeof the trick (not really a trick) to have this “in thebag” (or bottle...)

Soda Bottles and Dollar Bill - 1F20.37 Youmight not get your dollar back from these twobottles without a bit of care in performing thisdemonstration of the inertia of rest.

1G NEWTON’S SECOND LAW 11

Loose Hammer Head - 1F20.60 A hammer headcan be tightened by pounding the far end of thehandle on a table. This can be demonstrated usinga wood block and a short section of PVC. Poundthe PVC on the desktop and the wood block slidesdown a little with each blow. You can then causethe block to rise by pounding the top of the tubewith the palm of your hand.

1G NEWTON’S SECOND LAW

1G10 Force, Mass, and Acceleration

Motion Up an Inclined Plane - 1G10.13 Quan-titative studies of the motion of a body on an in-clined plane can be made quickly with this appa-ratus. A cart is pulled up the inclined plane bya mass suspended over a pulley at the top of theincline.

Acceleration Block - 1G10.25 A wood block isaccelerated by a mass on a pulley.

Mass on a Scale - 1G10.30 Hanging of masseson a spring scale show the reaction of the scale tomass times the acceleration of gravity.

12 MECHANICS

Atwood’s Machine - 1G10.40 The Atwood ma-chine is a simple pulley system to show accelera-tions and tensions in strings.

1G20 Accelerated Reference Frames

Dropped Slinky - 1G20.45 A partly extendedslinky is hung in the air and released for somepotentially unexpected results.

Float Accelerometer - 1G20.76 A fishing bob-ber suspended under water by a string moves inthe direction of an acceleration is experiences.

Acceleration Pendulum Cart - 1G20.85 Apedulum mouted to a cart shows that when movedat a constant velocity the pendulum feels no ac-celeration.

1H NEWTON’S THIRD LAW 13

1H NEWTON’S THIRD LAW

1H10 Action and Reaction

Push Me Pull Me Carts - 1H10.10 This demoreally gets the students involved in a commonphysics problem involving Newton’s Third Law.

Newton’s Sailboard - 1H10.20 Newton’s Sail-board shows action and reaction of a cart mountedfan.Toy Helicopter - 1H10.25

1H11 Recoil

Floor Cart and Medicine Ball - 1H11.10 Thisdemo show how a body recoils when some of it’smass is expelled.

1J STATICS OF RIGID BODIES

1J10 Finding Center of Gravity

Map of North Carolina - 1J10.10 This demowill show everyone in class where the center ofmass of North Carolina is (so long as you assumethat the state is perfectly flat, and consists of com-pletely uniform material throughout)!

14 MECHANICS

Center of Gravity of a Broom - 1J10.25 Thiswill show your students how to find the center ofgravity of a broom.

Equal Torques, But Not Equal Masses -1J10.251 This two-piece broom will show how un-equal masses can cause equal torques.

Meterstick on Fingers - 1J10.30 This is verysimilar to 1J10.25 Center of Gravity of a Broombut this one allows the object to be adjusted tosee if the technique still works.

Kneeling Human - 1J10.41 The two sexes havemany differences. This demo points out a not-so-obvious one: differing centers of gravity.

1J11 Exceeding Center of Gravity

Leaning Tower of Pisa - 1J11.10 If the realTower of Pisa was like this, there wouldn’t be toomany visitors, especially to the higher floors!

1J STATICS OF RIGID BODIES 15

Tipping Block on Incline - 1J11.15 This is avery vivid example of where the center of mass ofan object acts, and what happens when it movesoutside the base of the object.

Tower of Lire - 1J11.20 This center of mass demowill have your students scratching their heads andnot believing their eyes!

Double Cone - 1J11.50 How does that doublecone roll up that hill???

1J20 Stable, Unstab., and Neut. Equi

Fork, Spoon and Match - 1J20.20 Insert aspoon in the prongs of a fork. Place a match inthe prongs perpendicular to the spoon-fork matchon the lip of a glass of water. Drink from the glass.

Fourteen Nails on One - 1J20.25 Balance theset of nails as shown. You may want to practice.

16 MECHANICS

Spoon on Nose - 1J20.32 Clean the oil off yournose. Blow on a spoon. Hang it from your nose.

Balancing Bear - 1J20.45 A string will bestretched from one end of the lecture bench to theother.

Balancing Bird - 1J20.451 Show this toy birdbalancing on its beak. Weights are located in thetips of the birds wings keeping the center of gravitybelow the pivot point.

Wine Bottle Balance - 1J20.60 A small piece ofwood has a hole to hold the neck of the wine bottle.The wine bottle is balanced in an odd position. Ifyou do not want to use a wine bottle, we have ahammer that works just as well.

1J30 Resolution of Forces

Suspended Block - 1J30.10 The sides of the tri-angle are in the ratio of 3:4:5. Slide the inclineout of the way after the forces are balanced. Theblock will be suspended. The block has a massof 427 g. The masses needed to balance the per-pendicular and parallel forces are 342 g and 256 grespectively.

1J STATICS OF RIGID BODIES 17

Tension in a String - 1J30.20 Lift the mass witha Newton meter. The scale reads 5.5 Newtons.What happens if the Newton scale is pulled fromtwo sides with a force of 5.5 Newtons? The ap-paratus is set up with the scale facing away fromthe class. An additional mass and scale are pro-vided to show the weight of single mass. Massesare identical.

Rope and Three Students - 1J30.25 Have the two largest students pull on the ends of the rope.A small student can easily deflect the rope in the perpendicular direction.

Booms - 1J30.40 A boom is suspended at variousangles by a wire. A Newton meter can measurethe tension in the wire.

Sail Against the Wind - 1J30.60 First showwith the sail set so the cart is blown away from thefan. Then set the sail so the cart moves towardsthe fan.

1J40 Static Torque

Grip Bar - 1J40.10 By rotating the handle, at-tempt to raise the masses so that the bar is hori-zontal. Mass is variable.

Torque Beam - 1J40.20 Demonstrate angularequilibrium: when net torque and angular accel-eration are zero.

18 MECHANICS

Different Radii Discs - 1J40.25 This appara-tus rotates freely. There are 3 disks with differentradii so that masses can be hung to create differ-ent torques. There are also 4 adjustable masseson spokes to change the moment of inertia.

1K APPLICATIONS OF NEWTON’S LAWS

1K10 Dynamic Torque

Tipping Block - 1K10.10 Tip block over bypulling on hook with spring scale (Newtons). Varyangle between force and the block.

Walking the Spool - 1K10.30 Pull string. Anglebetween string and table determines which direc-tion the spool will roll. At some angle the spoolwill remain stationary.

Rolling Uphill - 1K10.50 Disk has a hiddenweight. The disk will roll uphill when the disk isplaced so that the weight is uphill from the disk’sgeometric center as shown in the diagram.

1K20 Friction

Friction Blocks - 1K20.10 Measure static frictionby noting the scale reading just before the blockslides. Pull block along lecture bench at a constantspeed to measure sliding friction.

1K APPLICATIONS OF NEWTON’S LAWS 19

Weight Dependence of Friction - 1K20.15Measure the force of sliding friction with a block.Mass can be varied.

Area Dependence of Friction - 1K20.20 Slidea block on its flat side and measure the force offriction. Flip the block to its side with feet andmeasure again. The surface area ratio is about10:1

Static vs. Sliding Friction - 1K20.30 Pull ona block with a spring scale until just before theblock moves. Note the reading on the spring scale.Pull the block slowly across the table. Comparethe spring scale readings. The top picture showsstatic friction, just before the block moves. Thebottom picture shows kinetic friction, while theblock is in motion.

Angle of Repose - 1K20.35 Raise the inclinedplane until the block begins to slide.

Front and Rear Brakes - 1K20.40 The truckhas holes drilled into both sets of wheels to allow ametal rod to be inserted to simulate locked brakes.Let car slide down incline and observe which givesmore stable braking.

1K30 PressureBed of Nails - 1K30.10 Lie down carefully on thebed of nails. Simutaneously make contact with alarge number of nails. The nails are spaced 1 nailevery 2 cm.

Balloon Bed of Nails - 1K30.15 Not crazy aboutlaying on a bed of nails yourself? We have a smallbed of nails for a balloon.When the balloon is rest-ing on the nails, several books can be stacked on itbefore it pops. To prove the balloon is not a spe-cial balloon, the bed of nails can be replaced witha single nail. The balloon will pop on contact.

20 MECHANICS

1L GRAVITY

1L20 Orbits

Orbits in a Spherical Cavity - 1L20.18 Several1” Pasco balls can be used to demonstrate orbitsin a concave mirror. A flat mirror can be set upto aid classroom visibility.

Conic Sections - 1L20.40 Each cut intersectingthe cone produces the shape of a different orbitalpath; circular, elliptical, parabolic, and hyper-bolic.

1M WORK AND ENERGY

1M10 Work

Pile Driver - 1M10.20 Raise the mass to the de-sired height and allow it to fall freely. If the massis raised twice as high, the nail will be driven twiceas far into the block of wood.

1M WORK AND ENERGY 21

Pile Driver with Pop Cans - 1M10.25 Raisethe mass to the desired height and allow it to fallfreely. Three empty coke cans will be supplied.

1M20 Simple Machines

Pulley System - 1M20.10 One and two pulleysystems can be hung from a ringstand and usedto raise weights. Use a spring scale to find themechanical advantage.

Levers - 1M20.40 Discuss the advantage of first,second and third class levers.

1M40 Conservation of Energy

Bowling Ball Pendulum - 1M40.10 Standstraight. Bring the bowling ball up to your noseand release it WITH NO INITIAL VELOCITY.STAND VERY STILL until the ball swings back.DO NOT LEAN FORWARD.

Stopped Pendulum - 1M40.15 Raise the pen-dulum to one side and release it. The pendulumreaches almost the same maximum height at bothends of its swing. Some energy is lost. The rodused as the stop bar can be set to different heights.

22 MECHANICS

Loop the Loop - 1M40.20 Release the ball nearthe top of the track. Energy losses make the min-imum height (necessary to complete the loop) sig-nificantly higher than the calculated value.

Ball in Track - 1M40.30 A ball is released from apoint on either incline. The ball loses little energywith each roll and rises to almost the same heighton the other end of the track.

Ballistic Pendulum - 1M40.40 Cenco apparatusis available. Ball can be fired with different ve-locities and the pendulum movement is measuredwith protractor.

Rattleback - 1M40.90 Place the rattleback flatside up. Press down, quickly release and it willspin counter clockwise. Spin it clockwise to showthat it stops, rattles, and spins counter clockwise.Spin the rattleback clockwise.

1N LINEAR MOMENTUM AND COLLISIONS

1N10 Impulse and Thrust

Egg in Sheet - 1N10.20 Have two students holda sheet as shown. Toss an egg into the sheet. RE-MOVE THE EGG BEFORE THROWING AN-OTHER. Demo Room needs notice to purchaceeggs.

1N LINEAR MOMENTUM AND COLLISIONS 23

1N20 Conservation of Linear Momentum

Walk the Plank - 1N20.70 As the instructorwalks along the attached floor carts, they willmove in the opposite direction. The velocity ofthe floor cart is observable to the students by themoving flag. The result can be changed by carry-ing a medicine ball or placing the medicine ball onthe cart.

1N22 Rockets

Water Rocket - 1N22.20 Fill the rocket with acap full of water. Insert pump into rocket, slidecatch into position and pump 20-25 times. To re-lease the rocket, aim and slide catch off. You willprobably get wet. Pump the same number of timeswithout the water to show the difference in range.

Balloon Rocket - 1N22.25 Blow up balloon andrelease it in the in the lecture hall.

1N30 Collisions in One Dimension

Collision Balls - 1N30.10 Observe the effect ofdisplacing different numbers of balls. Try one ballfirst, then two and so on up to five balls at once.

Irritating Collision Balls - 1N30.12 The firstball sits motionless while the second ball rotatesaround the stick. After the collision, the first ballgoes around the stick while the second is motion-less. The toy is habit forming to play with, butbecomes annoying very fast if you are watching.Crack, Crack, Crack,...

24 MECHANICS

3 to 1 Collision Balls - 1N30.20 Two pendula onbifilar suspension have a mass differential of 3 to 1.Bring the smaller pendula back and release. Whenit collides with the larger pendula, they both recoilat the same rate to the same height. When theycollide again, the large pendula stops while thesmall pendula recoils. The process repeats severaltimes.

Impulse Pendulum - 1N30.50 Two pendulumsare allowed to collide with a piece of wood. Onependulum is made from a super bounce ball. Iteasily topples the block. The second ball is a non-bouncing ball and fails to topple the block.

Ball-Block Collision - 1N30.53 Bounce and no-bounce balls are used to discuss impulse. The no-bounce ball rolls down the track and collides withthe block of wood failing to knock it over. Thebounce ball is then rolled down the track and eas-ily knocks over the block. Both balls are the samesize and mass.

Double Ball Bounce - 1N30.60 Place a one smallball on top of a larger ball and drop from a heightof about 4 feet. Warn the audience that the ballsmay fly astray.

1Q ROTATIONAL DYNAMICS 25

Astro-Blaster - 1N30.601 The impluse requiredto stop the system when striking the ground is ap-plied to the larger and smaller ball equally. Thesmaller ball will accelerate faster since it has asmaller mass. Use this demonstration to discussconservation of momentum. The following state-ment is from the package: “The gravitational col-lapse of the dying star is illustrated by Astro-Blaster’s fall to the surface. The shock wave ac-celerating outward through the star is illustratedby a wave of increasing speed as the result of theimpact which is felt by the lighter balls nearer thetop. The supernova explosion and release of cos-mic rays is illustrated by the rapid departure ofthe top ball at high speed” - Stirling A. Colgate,Astrophysicist

1Q ROTATIONAL DYNAMICS

1Q10 Moment of Inertia

Inertia Wands and Two Students - 1Q10.10Two wands have the same mass. One wand hasthe mass concentrated at the ends. The other rodhas the mass concentrated at the center. Have twostudents flip them back and forth as fast as theycan. This student holds the wand with the massconcentrated at the center.

Balancing a Bat - 1Q10.101 A dowel with aweight attached at one end can be used to showRotational Inertia. Show that it is easier to bal-ance the dowel with the weight far from your handand harder when the mass is close to your hand.This is similar to balancing a baseball bat.

Racing Disks - 1Q10.40 Disks and hoop haveequal masses. Release both disk and hoop at topof inclined plane at the same time. Also avail-able upon request: PVC tubing, short wooden bar,ping-pong ball, two solid balls of unequal mass andradius.

26 MECHANICS

Racing Soups - 1Q10.50 A variety of soup cansare supplied to roll down an incline. Beef Bouillon,Cream of Mushroom, and Tomato soups are usu-ally compared because of their different momentsof inertia.

1Q20 Rotational Energy

Kinetic Energy of a Rolling Disk - 1Q20.30

Faster Than ’g’ - 1Q20.50 Place the ball in theholder. Pull the stick to release. The ball ’jumps’into the cup

Falling Meter Sticks - 1Q20.60 Show the timeof the fall varies with the length.

1Q30 Transfer of Angular Momentum

Passing the Wheel - 1Q30.10 Tip the spinningwheel 180 degrees. Hand to a student who turns itanother 180 degrees and hands it back. Repeat un-til spinning too fast to make the hand-off. You canadd to or subtract from your angular momentumdepending on which direction you flip the wheel.


Drop Bags of Rice - 1Q30.20 While spinningdrop 10 lb bags of rice. The changing mass doesnot affect the speed of the rotation. The bags ofrice take their angular momentum with them.

Catch the Ball - 1Q30.30 Catch a bag of rice atarms length

1Q40 Conservation of Angular Momentu

Rotating Stool with Dumbbells - 1Q40.10Start spinning and bring the masses towards yourchest slowly. Your angular velocity will increase.

Stability of Orbits - 1Q40.20 Conservation ofangular momentum can be shown nicely with thisapparatus. Start the bar rotating and pull onthe center string. As the mass is pulled towardsthe center, the angular velocity increases. Thisdemonstration is similar to the rotating stool withmasses demonstration.

28 MECHANICS

Rotating Hoberman Sphere - 1Q40.22 Con-nect a ball bearing fishing swivel to a HobermanSphere mobile. Spin the mobile and pull thestring. The sphere will spin faster when it col-lapses.

Governor - 1Q40.23 The position of the balls can be used to describe the rate of rotation.

Pulling on the Whirligig - 1Q40.25 Spin theball/cylinder around while holding the hollowtube. Move the lower ball/nut up and down tochange the radius of the circle and the angularvelocity.

Rotating Stool and Bicycle Wheel - 1Q40.30The rim of the wheel is weighted. Tip spinningwheel while seated on stool. Stool will rotate. Tipin opposite direction to rotate the other way.

Drop the Cat - 1Q40.33 Turn yourself aroundon a rotating stool by rotating a mass on a shortrope. Approximately 1 Kg of mass is attached toa 40 cm rope. Spin the mass around your headas a cat would spin its tail. Show that a cat canflip from its back to its feet while its total angularmomentum remains equal to zero.

Hero’s Engine - 1Q40.80 Show that the momentum of the steam is countered by the spinning ofthe Hero’s Engine.


1Q50 Gyros

Bicycle Wheel Gyro - 1Q50.20 Rotating bicyclewheel is balanced on a pole.

Gyro with Adjustable Weights - 1Q50.201 Ademonstration sized gyro is at the end of a pivot-ing rod with an adjustable counter weight.

Double Wheel Gyro - 1Q50.25 Two wheels aremounted coaxially on the end of a pivoting rod.Try the standard demos with the wheels rotatingin the same direction and in the oposite directions.

Mitac Gyro - 1Q50.30 The rotor is driven at 150rpm by a motor. Masses can be added.

30 MECHANICS

Suitcase Gyro - 1Q50.40 This demo includes awheel with an internal motorized gyroscope and asuitcase. The wheel may be used alone or placedin the suitcase.When used alone, the wheel tends to stand up-right. Hit it on its sides to demonstrate this.When used in the suitcase, ask a student to walkin a CW circle and then in a CCW circle. Thissuitcase will extend away from the student in onecase and toward the student in the other case.

Trapeze Gyro - 1Q50.74 Toy gyroscope with string, acrobatic stand and power cord.

1Q60 Rotational Stability

Tippee Top - 1Q60.30 When a top is spinning it flips over to spin on its stem.

Spinning Football - 1Q60.35 Show how a foot-ball moves upright when spun on its flat side.

Ellipsoid - 1Q60.37 Ball is spun while resting ona cushion of air.

Tossing the Book - 1Q60.40 Spin the book (orboard) about its three principle axes. The bookwill be stable when spinning about the axes withmaxumum and minimum moments of inertia. Thebook will not be stable spinning about the axiswith the intermediate moment.

1R PROPERTIES OF MATTER 31

1R PROPERTIES OF MATTER

1R10 Hooke’s Law

Stretching a Spring - 1R10.10 A 50 gram masshanger hangs on a spring. Begin with 50 grams onthe hanger. This brings the spring into its linearrange. Mark the position of the bottom of thehanger with a clamp. Add 50 gram masses to thehanger marking the position after each addition.

Compressing a Spring - 1R10.101 A large spring can be used to show that Hooke’s works forcompression as well.

1R20 Tensile and Compressive Stress

Bending Beam - 1R20.20 A mass hangs frommeter stick resting on two supports. Compare thebending in the meter stick flat and on edge. Lowermass gently when changing sides as the METERSTICK MAY BREAK

1R30 Shear Stress

Shear Book - 1R30.10 A large text book will besupplied. Push the text to the side from the top.

32 MECHANICS

1R40 Coefficient of Restitution

Coefficient of Restitution - 1R40.10 Drop ballsof different materials onto a plate. Compare theheights reached after bouncing by marking the po-sitions on the meter stick.

Bounce/No Bounce Balls - 1R40.30 Two ballslook and feel identical. One bounces and the otherdoes not.

1R50 Crystal Structure

Ball-Spring Model - 1R50.18 Red balls, repre-senting atoms, are connected with springs, repre-senting interatomic bonds. There are two modelsas shown in the picture: one with more red ballsand stiffer springs; another with fewer balls andless stiff springs.

Molecular Model Kit - 1R50.20 Demonstratethe fundamental concepts of chemical change andthe nature of compounds with this set of molecu-lar models. Students can visualize the three di-mensional nature of a molecule. There are 54balls, 10 Carbon(black), 2 Nitrogen(blue) 1-14/”diameter. 28 Hydrogen(yellow), 6 Oxygen(red),4 Chlorine(green), 2 Bromine(orange) and 2 io-dine(purple) 1-1/8” diameter. 40 wooden peg and10 spring connectors.

33

Fluid Mechanics

2A SURFACE TENSION

2A10 Force of Surface Tension

Cohesion Plates - 2A10.35 The demonstration consists of two circular metal plates with handles.One side of each plate is ground to uniform smoothness. Place a drop or two of water on the smoothface of one plate. Bring the plates together and turn plates to spread the water uniformly over thesurfaces. Pull the plates apart and note the force required.

Surface Tension Bottle - 2A10.60 Fill a bottlewith water, insert a stopper with a hole and invert.Insert a large pencil into the flask to show that thestopper does indeed have a hole.

2A20 Capillary Action

Capillary Tubes - 2A20.10 Five capillary tubesof increasingly smaller diameter draw from thesame reservoir. This demonstration is small. Avideo camera and monitor should also be re-quested for larger rooms.

2B STATICS OF FLUIDS

2B20 Static Presssure

Pascal’s Vases - 2B20.40 Show that the liquidrises to the same height in each vase. Coloredwater will be used to help the students see thedemonstration.

34 FLUID MECHANICS

2B30 Atmospheric Pressure

Atmosphere Bar Lead Bar - 2B30.05 A 1” x1” x 35” steel bar weighs 14.7 lbs., the force of theatmosphere on 1 square inch. Good as a visual aidor to pass around the room.

Crush the Soda Can - 2B30.15 Fill a pop canwith steam by boiling a small amount of water init. Quickly turn upside-down in a beaker of coldwater. The steam condenses creating a partial vac-uum inside the can. This allows the atmosphericpressure to crush the can. Very dramatic.

Magdeburg Hemispheres - 2B30.30 Make surethe valve is open. Turn on the vacuum pump toevacuate the hemispheres. Shut the valve and re-move the hose. Have two students try to pull thehemispheres apart.

Magdeburg Plates - 2B30.301 Two flat platesare separated by an O-ring. A syringe and one-way check valve system are used to create a par-tial vacuum between the plates. Two O-rings areavailable so that larger and smaller chambers canbe created.

Suction Cups - 2B30.36 These two rubber suc-tion cups can be used as magdeburg Hemispheresor to pick up a chair. The diameter of each suctioncup is 8cm.

Plumbers Friend - 2B30.361 Use the PlumbersFriend to pick up a chair or close a door. (We havenot cleaned any drains with this demo, at least notlately:-)

2B STATICS OF FLUIDS 35

Glass and Card Trick - 2B30.45 The demon-strator fills a glass with water and places a pieceof plastic over the top. When the glass is inverted,the plastic will not fall off and the water will notflow out.Pressure Globe - 2B30.451 A hallow glass globe with two openings with a balloon stretched overone opening and a rubber stopper over the second.

Vacuum Cannon - 2B30.70 This demonstrationinvolves a ping pong ball and an evacuated PVCpipe. The ends of the pipe are sealed by sheets ofReynolds Wrap Heavy Duty aluminum foil (withthe ball inside). The air is then evacuated and asthe bottom layer is punctured, the ball is forcedout of the top end of the cannon by air rushing infrom the bottom. A single ping pong ball can comeout dangerously fast. It is recommended that youuse 6-10 ping pong balls reducing the muzzle ve-locity and increasing the effect by bouncing pingpong balls all over the place.

2B40 Density and Buoyancy

Weigh Submerged Block - 2B40.10 Weigh thebrick in air and then in water. The brick displacesabout 300 ml of water which can be measured bythe class using a large beaker.

Archimede’s Principle - 2B40.20 A bucketand a close fitting cylinder are used to showArchimede’s principle. Suspend the cylinder froma Newton meter below the bucket and lower thecylinder into an overflow can full of water. Showthe bouyant force as the difference in the scalereading before and after lowering the bucket cylin-der into the water. Take the water that overflowedinto the catch bucket and pour into the bucket(above the cylinder). The weight of this waterwill equal the buoyant force and return the scalereading to its value before the cylinder was loweredinto the water.Volume of Plummet: 100 cm3 Mass of Plum-met: ¿= 120g Volume of Cavity in Bucket: 100mlDimensions: 5.5cm X 5.5cm X 5.5cm Weight ofBucket and Plummet: 1.5 Newtons

36 FLUID MECHANICS

Buoyancy, Aquarium, and Nails - 2B40.28To show bouyant force is related to the displacedvolume of water, the demonstrator uses assortedmasses, a container of water and some aluminumfoil. The demonstrator makes a small boat outof the aluminum foul and several masses can befloated on the surface. Finally, the foil can bewadded into a ball arouund the mass and it willsink.

Floating Bowling Balls - 2B40.29 A fish tank,10 Lb. and 14 Lb. bowling balls are supplied. The14 Lb. bowling ball sinks while the 10 Lb. floats.

Floating Coke Cans - 2B40.291 A fish tank,Coke and Diet Coke are supplied. The Coke sinkswhile the Diet Coke floats.

Cartesian Diver - 2B40.30 Squeeze the sides ofthe coke bottle and the eye dropper will sink. Letgo and it will rise up again. The demo shouldwork great until the barometric pressure changessignificantly.

Density Ball - 2B40.59 This 4” steel ball demonstrates the effect of temperature on the densityof a liquid. When placed in cool water (15 degrees C) it floats. When placed in warm water (30degrees C) it sinks. You will be supplied with two beakers of water at the desired temp eratures.

2C DYNAMICS OF FLUIDS 37

Poly Density Bottle - 2B40.711 The bottle in-cludes 4 substances with densities in the followingorder (from small to large): alcohol, white beads,blue beads, saltwater.

2C DYNAMICS OF FLUIDS

2C10 Flow Rate

Velocity of Efflux - Three Hole Can Exper-iment - 2C10.10 The three hole can experimentshows that liquid pressure depends upon the depthof the liquid.

2C20 Bernoulli Force

Venturi Meter - 2C20.26 The Venturi tube con-sists of a plain tube with a smooth constrictionin its bore at the middle. It is found in carbure-tors, fluid flow meters, and aircraft airspeed indi-cators. This version is made of glass and has threeside tubes for attaching a manometer. When highpressure air is applied from the air tank, the waterlevel in the three manometer legs is clearly differ-ent.

Floating Ball - 2C20.30 Turn on the blower.Place the beachball in the air stream. Change theangle of the air stream. Notice how the ball rollsback to the wind source when you turn the bloweroff.

38 FLUID MECHANICS

Floating Ball (leaf blower) - 2C20.301 Turnon the leaf blower. Place the beach ball in the airstream. Change the angle of the air stream untilthe ball falls. Notice how the ball rolls back to thewind source when you turn the blower off.

Floating Ball (hair dryer) - 2C20.302 A hairdryer and a ping pong ball are provided. The pingpong ball can be suspended in the air stream fromthe hair dryer.

Ball and Funnel - 2C20.35 A large glass funnel hangs upside-down. Attach air supply to thenarrow end. Hold the ping-pong ball in the funnel and release it.

Attracting Sheets - 2C20.45 Blow air through a straw between two plates. Since the inside pressureis less, the plates “attract”

Boomerang - 2C20.55 This is a modern return-ing boomerang made from carbon fiber-reinforcedplastics. It is supposed to make an elliptical pathbefore it returns to the hand.Principle: The gyroscopic spinning keeps theboomerang vertical. The wings are shaped likeairfoils. Because of the forward motion coupledwith the spinning motion, the top wing has more“lift”. This causes creates a torque attemptingto rotate the boomerang towards the horizontal;however, because of the angular momentum, thetorque instead causes the boomerang to precess orcurve back to the thrower.

Raketti Block - 2C20.59 ask the students to try to remove the cylindrical block from the base w/ousing their hands. the trick is to blow almost straight down from above the cylinder.

Curve Ball - 2C20.60 A Trac-Ball set is used tospin a Styrofoam ball while throwing it. Place theball in the lower end of the track. Throw with aquick motion, keeping the track in a vertical planefor upward deflection. The track should be nearlyvertical when the ball leaves it. This takes a littlepractice.

2C DYNAMICS OF FLUIDS 39

2C30 Viscosity

Terminal Velocity of Dropped Balls -2C30.50 Steel, Aluminum and Glass balls aredropped into a graduated cylinder filled with Glyc-erin. Pictured falling is the aluminum ball withthe glass ball at the bottom.

Terminal Velocity - Styrofoam - 2C30.60 Dropsome 1 inch Styrofoam flakes and observe theirvelocity. The flakes reach their terminal velocitywithin a few centimeters.

Terminal Velocity - Coffee Filters - 2C30.65 Drop crumpled and uncrumpled coffee filters toobserve different terminal velocities.

2C50 Vorticies

Vortex Cannon - 2C50.15 This is a toy called an“Airzooka” that is basically an air gun. One endis covered with a diaphram attached with elasticstrings that can be extended and released. Airthen shoots out the other end. It can be used toknock over stacked cans or shot at students.

Vortex Cannon - Large - 2C50.151

Tornado Tube - 2C50.30 Two cola bottles areconnected, one filled with water. After beingturned upside down, only a small amount of waterflows into the lower bottles because of the reducedpressure above. By swirling the upper bottle incircles, water begins to pour again and a vortex iscreated.

40 WAVES AND OSCILLATIONS

Waves and Oscillations

3A OSCILLATIONS

3A10 Pendula

Simple Pendulum - 3A10.10 The length of thependulum is adjustable. A timer can be used tomeasure the period. If you want a longer pen-dulum, use the bowling ball suspended from theceiling.

4 to 1 pendulum - 3A10.14 Release the two pen-dula simultaneously. The small pendulum has alength of 25 cm to give a one second period. Thelonger pendulum is 1 m and has a two second pe-riod.

The Pendulum Wave - Small - 3A10.141 Sev-eral pendula of different lengths are adjusted tohave successively increasing periods. Use the sup-plied stick to simultaneously start all the pendu-lums. The different periods cause the pendulumsto cycle through all possible relative phase rela-tionships before returning to the original position.Multiple wave patters can be observed during thiscycle.This small version of the “pendulum wave” can beplaced on the document camera and viewed fromabove. It works well this way in a large classroom.

3A OSCILLATIONS 41

The Pendulum Wave - Large - 3A10.142 Sev-eral pendula of different lengths are adjusted tohave successively increasing periods. Use the sup-plied stick to simultaneously start all the pendu-lums. The different periods cause the pendulumsto cycle through all possible relative phase rela-tionships before returning to the original position.Multiple wave patters can be observed during thiscycle.

Different Mass Pendula - 3A10.17 4 pendulaof the same length and size but different massesare released at the same time. Observe that theperiod is the same for all.

Torsional Pendulum - 3A10.30 A mass is sup-ported by a wire.

3A15 Physical Pendula

Physical Pendulum - 3A15.20 Compare the pe-riod of a meter stick pivoted at its end and a point1/3 from the end. Also compare the period tothat of a simple pendulum 2/3 of the length of thephysical pendulum.


Sweet Spot of Baseball Bat - 3A15.50 A base-ball bat and a simple pendulum are suspendednext to each other. Adjust the length of the sim-ple pendulum until its period matches that of theswinging baseball bat. Strike the bat with thesupplied stick at the location of the level of thependulum bob. The bat will recoil more at thislocation.

3A20 Springs & Oscillators

Mass on a Spring - 3A20.10 A 115 g mass oscil-lates on a spring with a period of about 1 second.The spring constant is approximately 14 N/m.

3A40 Simple Harmonic Motion

Gee-Haw Whimmydiddle - 3A40.901 One ofthe sticks has notches cut out of it and a propelleron the end. Rub the second stick over the notcheswith your finger pressed into the notched stick,and the propeller will turn one way. Then extendyour finger over the notched stick and pull backso that you are now pull against the notched stickwhile you’re rubbing it, and the propeller will turnthe other way.

3A50 Damped Oscillators

Damped Harmonic Oscillator - 3A50.10 Amass on a spring is set in a large beaker of wa-ter. The damping action is very nearly critical

3A OSCILLATIONS 43

Damped Harmonic Oscillator with PositionPlot - 3A50.101 A cart is placed on an air trackand springs are connected to the cart on both endsso that it oscillates back and forth. A mechanicaldriver is attached to one spring to force oscilla-tions, and a position sensor is connected to a lap-top running Data Studios to plot the position ofcart as a function of time.

3A60 Driven Mechanical Resonance

Tacoma Narrows Bridge Collapse - 3A60.10 The “dead dog” version runs 10:00 on video disc.The film loop runs 4:40

Driven Mass on a Spring - 3A60.47 A mass on a spring is driven by a variable frquency oscillatorcoupled to the mass by a smaller spring.

Metal Resonance Strips - 3A60.52 Three stripsof metal are bolted together, each of the six endsa different length. They are attached to a me-chanical vibrator that is connected to a frequencygenerator. Each of these ends has different res-onant frequencies and resonates independently ofthe others, so classes can see the relationship be-tween length and resonance.

3A70 Coupled Oscillations

Wilberforce Pendulum - 3A70.10 When themass oscillates it passes its energy back and forthbetween its vertical and tortional modes.

Coupled Pendula - 3A70.20 Five pendula hangfrom a flexible wood frame. Start one pendulumoscillating. The pendula will pass the energy backand forth with a pendula of equal length.

Upright Coupled Oscillator - 3A70.201 matching sets of 3 vertical pendulums of varying heights.when clamped to a surface (to prevent the base from moving), move one of the masses and thematching height will start to move.


Spring Coupled Pendula - 3A70.25 You can show several modes of oscillation with the piece ofequipment. If the pendula are started in phase or 180 degrees out of phase, energy is not transfered.If one pendula is started 90 degrees out of phase, then the energy is passed back and forth betweenthe two pendula.

Double Pendulum - 3A70.35 Two golf balls arestrung together about half a meter apart and thetop ball is hung half a meter from the bar. Theswinging balls illustrate a chaotic pendulum sys-tem.

3A80 Lissajous Figures

Lissajous Sand Pendulum - 3A80.10 This apparatus consists of a heavy plastic cone-shapedvessel supported by 3 cords. These 3 cords are tied to two cords which form the support for thependulum. A ring which may be moved along the cords so as to bring them together any placebetween the point of support and the cone. By this means a double pendulum is made which can begiven vibrations in two different directions. The pendulum may be made to swing in two differentplanes and to swing with two different periods. One plane of swing is fixed and is determined bythe supporting of the two cords. The other plane of swing may be made anything desired by theoperator but is usually made to swing at right angles to the upper plane. The period of the swingof the lower pendulum and the upper pendulum depends upon the location of the movable collar.The periods of the two swings may thus be adjusted to any desired ratio. some very interesting sandpatterns may be obtained which illustrate the result of combining two harmonic motions of differentperiods.

3A95 Non-Linear Systems

Chaotic Pendulum - 3A95.52 This apparatusdemonstrates chaos. The demonstrator pushes onone of the three arms and the chaotic pendulumwill rotate and gyrate for several minutes. It is fas-cinating to watch. We can also setup two identicalpendulums so your class can watch the deviation.

3B WAVE MOTION 45

Two Chaotic Pendula - 3A95.521 Start bothpendula at the same time and observe the differ-ence in paths.

Pump a Swing - 3A95.70 Give the penduluman initial swing. When it reaches the equilibriumpoint, pull down on the string. The amplitude willincrease.

3B WAVE MOTION

3B10 Transverse Pulses and Waves

The Wave - Transverse - 3B10.05 Have stu-dents do a standing wave as seen at sporting are-nas.

Rubber Rope - 3B10.10 A long rubber rope isavailable. Pluck the end of the taut rope to createa pulse. Vary the tension to vary the speed of thepulse.

Speed of a Slinky - 3B10.17 The slinky is crit-ically damped at one end by hooking it arounda pole. Have students observe a transverse wavetraveling the length of the table.

Slinky on Table - 3B10.20 A slinky stretched thelength of the lecture bench. One end is attachedto a rod clamped to the end of the bench. Jerk thespring sideways to create a pulse. Observe how apulse reflects from a fixed or free end. The free endis approximated by tying the end of the slinky toa light string.

Transverse Wave Generator - 3B10.30 This isthe Shive/Bell Labs Wave Model Thin rods aremounted on a fine wire that twists easily. Displacethe rod at one end to create a torsion pulse orwave. The other end can be left free to move orfixed in place.


Hand Crank Wave Machine - 3B10.51 An oldcrank style machine is useful for showing a sinewave. As the handle is turned, the fluorescent or-ange balls move up and down as a sine wave.Without MarkerWith Marker

3B20 Longitudinal Pulses and Waves

The Wave - Longitudinal - 3B20.05 Have students on one side of the class lean into the personnext to them. As someone gets leaned into, they should start to lean also. The result is a humanlongitudinal wave.

Suspended Slinky - 3B20.10 Display propaga-tion, reflection, interference, as well as a numberof other longitudinal wave phenomena. Simply in-duce motion in the spiral spring using the wave ex-citers located at each end. To vary the frequencyof the wave motion, slide the wave exciter massesup or down. The black spiral wave spring in frontof the contrasting white cloth backdrop makes thedemonstration easy for everyone to see.

Longitudinal Wave Demonstrator - 3B20.30The purpose of the Longitudinal wave demonstra-tor is to show propagation, reflection, superposi-tion and various resonance modes analogous tothose of many musical instruments. The appa-ratus consists of twenty-one vertically mountedblack steel bars on parallel rails. The rods aremounted or pivoted at a point slightly above thecenter of gravity and coupled together with twolong springs. The top ends of the rods are paintedwhite and have a fluorescent dot on one side fordemonstrations using ultraviolet light.

Hand Cranked Longitudinal Wave Genera-tor - 3B20.35 Similar to the hand cranked trans-verse wave generator. A marker can be placed onany bar to show that individual particles do nottravel.Without markerWith Marker

3B WAVE MOTION 47

3B22 Standing Waves

Melde’s Vibrating (elastic) String - 3B22.10A speaker drives an elastic rope. Vary the drivingfrequency by adjusting the signal generator. Thiswill produce standing waves with up to six or sevenantinodes. A strobe can be used.

Melde’s Vibrating String (variable tension)- 3B22.101 A speaker drives a string that is hungover a pulley and attached to a mass hanger. Varythe mass or frequency. A strobe can be used.

Transverse Standing Waves - 3B22.30 Use theShive Transverse Wave demo to produce standingwaves.

Longitudinal Wave Spring - 3B22.51 Thespring is driven by a mechanical driver. Stand-ing longitudinal waves can be produced.

Longitudinal Standing Waves - 3B22.60 This apparatus can be used to setup standing longitu-dinal waves. It consists of many steel rods connected at two points by springs.

3B25 Impedence and Dispersion

Impedance Matching - Shive Model -3B25.10 Thin rods are mounted on a fine wire thattwists easily. Displace the rod at one end to createa torsional wave or pulse. Sets of rods of differentlengths are connected to show reflection and re-fraction with matched or unmatched impedances.


Reflection - Shive Model - 3B25.20 Send a sin-gle pulse down the Longitudinal Wave apparatus.Watch the reflected pulse. Repeat with the endclamped.

3B27 Compound Waves

Wave Superposition - Shive Model - 3B27.151) Start postitive pulses from each end of the Shivemodel. 2) Start a positive pulse on one end and anegative pulse on the other end.

3B30 Wave Properties of Sound

Speed of Sound in a Metal - 3B30.20 With this set-up, you will measure the speed of sound inone of the long aluminum PASCO tracks. A microphone is place at one end of the track. When youstrike the other end of the track with a metal rod, it not only makes a sound, but it also completesan electric circuit that triggers Data Studios to begin recording sound from the microphone. Theplot showing the time of trigger and the time when the sound reached the microphone can then bedisplayed on the projector.

Bell in a Vacuum - 3B30.30 Switch on the vac-uum pump. Connect the battery to the bell. Ittakes 2 minutes to pump down to a good vacuum.

3B40 Doppler Effect

Doppler Ball - 3B40.10 A buzzer and batteryare in a tennis ball at the end of a long string.Whirl the buzzer in a horizontal circle over yourhead. Point out the difference in sound betweenthe moving and stationary buzzer.

3B WAVE MOTION 49

Doppler Spear - 3B40.20 Rub the rod with waxpaper. Stroke the rod until it sings. Pick up therod at its midpoint and quickly thrust it towardsthe class. But please don’t let it go:-)

Doppler Reed - 3B40.25 A variable speed mo-tor rotates an arm with a reed at one end. Thisdemonstration can be dangerous. We recommendthe Doppler Ball

3B50 Interference and Diffraction

Ripple Tank - Single Slit - 3B50.10 Single slitdiffraction with varying slit and wavelength.

Chinese Water Spouting Basin - 3B50.101Moisten your hands and rub the brass handlesback and forth. The friction will cause the bowl toresonate, and the interference pattern of the waterin the bowl will cause it to jump out of the bowl.

Ripple Tank - Two Point - 3B50.20 The shadows from a shallow water tank are projected ontoa screen with an overhead projector. Use two point sources to show interference.

Ripple Tank - Double Slit - 3B50.25 Plane waves are passed through two slits made of wax. Thewax blocks can be moved to change theslit widths.

Ripple Tank Film Loops - 3B50.30 ”Interference of Waves” 4:00 min, “Single Slit Diffraction”3:30 min, “Multiple Slit Diffraction” 3:25, Cinema Classics disc2/side D chapters 11,21

Moire Pattern and Transparencies - 3B50.40Pairs of identical transparencies have circular wavepatterns. Place transparencies on the overheadprojector. Vary their relative positions to producedifferent interference patterns.


3B55 Inter. and Diff. of Sound

Speaker Bar - 3B55.10 A variable function gen-erator drives two speakers which are mounted onthe ends of a 8 ft board. The generator will bepreset to 3 kHz. The speaker bar is set on a pivot.Direct the students to plug one ear and listen forvariations in intensity while you slowly turn theturntable. Alternately, have the students movetheir heads back and forth while plugging one ear.(The speaker does not move.) A set of switchesallow either speaker to be turned off.

Phase Interference of Speakers - 3B55.20 Two speakers play a 60 Hertz tone. While the speakersare in phase, everyone can hear the tone. Using a switch box, one of the speakers can be thrown outof phase causing destructive interference. The sound almost completely disappears. Music can alsobe played through the speakers to emphasis the importance of hooking up ones stereo correctly.

Baffle and Speaker - 3B55.30 Set the generator to 350 Hz. Adjust the amplitude so the sound isbarely audible. Place the baffle in front of speaker.

Baffles and Resonators - 3B55.31 A tuning forkheld in the hand and struck with a rubber malletemits a feeble sound audible for only a few feet,owing to destructive interference between differenttrains of waves generated by the fork. It is possibleto eliminate much of the interference and make thefork sound loudly by holding it in front of a slitcut in a piece of cardboard. The fork should beheld close to the cardboard but not in contact withit, with the plane of its prongs either parallel orperpendicular to the cardboard.

3B60 Beats

Beat Forks - 3B60.10 Strike the tuning forks withthe rubber mallet and observe the beats. Vary thebeat frequency by adjusting the position of thesmall mass on the tuning fork.

3B WAVE MOTION 51

Beat Bars - 3B60.11 Two identical bars mountedon resonator boxes. One may be detuned by amovable weight on one end to show beats.

Beat Speakers - 3B60.19 Two frequency gener-ators are hooked up to speakers. Tune the twofrequency generators together and then vary one.

3B70 Coupled Resonators

Sympathetic Resonance - 3B70.10 Use twomatched tuning forks on boxes. Strike one, bringthe other close, then stop the first.

Ames Tube - 3B70.101 Use the Ames Tube andtwo associated tuning forks to show sympatheticvibrations, beats and mechanical coupling.

Coupled speaker/tuning fork - 3B70.20 A tun-ing fork can be made to resonate by driving it witha speaker.


3C ACOUSTICS

3C10 The Ear

Auditory Demonstrations - 3C10.001 In 1978,a set of auditory demonstration tapes was releasedby the Laboratory of Psychophysics of HarvardUniversity. These demonstrations had been pre-pared by a team led by Prof. David M. Greenand were sponsored by a grant from the Na-tional Science Foundation. The set contains 20recorded demonstrations on psycoacoustics plusan explanatory booklet.

3C20 Pitch

Range of Hearing - 3C20.10 Two large speakerson a cart are hooked up to a function generatorand amplifier. Vary the frequency of the signal asthe class listens. Have the class raise their handsonly as long as they can hear at the extreme endsof the hearing range. At subsonic frequencies youcan see the speakers vibrate. DO NOT LEAVETHE POWER ON A SUPER OR SUBSONICFREQUENCY AS THIS WILL BURN OUT THESPEAKERS. Speaker limitations do not allow youto test students ability of hearing low frequencies.

3C30 Intensity and Attenuation

Digital Sound Level Meter - 3C30.22 A meterwith a range from 30dB to 130dB.

3D INSTRUMENTS 53

3C50 Wave Analysis and Synthesis

Fourier Synthesizer - 3C50.10 Any periodicwaveform can be expressed as an infinite sumof trigonometric functions, consisting of a sineor consine function and its successive harmonics.With this piece of equipment, you can demon-strate and investigate this mathematical idea,adding a succession of sine wave harmonics andviewing the results waveform on an oscilloscope.

Electronic Keyboard - 3C50.12 A Yamaha key-board with a large variety of preprogrammedsounds is available for use in class. Sounds canbe monitored with a oscilloscope or digitized witha Macintosh.

3C55 Music Perception and the Voice

Microphone and Oscilloscope - 3C55.71 An excellent tool for showing waveforms of differentsounds to a large class. This demonstration can be done using a traditional oscilloscope with a videocamera or using a computer with Pasco’s Science Workshop to digitize the signal. We recommendyou come look at this first if you have never used it.

3D INSTRUMENTS

3D20 Resonance in Strings

Sonometer - 3D20.10 Investigate the dependenceof pitch on the length, tension and thickness of astring.

3D30 Resonance Cavities

Kroogah Tubes - 3D30.35 When spun aboveyour head, turbulence is created by the moving airthrough the tube. This turbulence is compoundedby the ridges in the sides of the tube. Sound wavestraveling out of the open ends of the tube partiallyreflect back into the tube. If the wavelength of thereflected wave matches the wavelength of the in-coming wave, these waves reinforce one another,resonating of greater amplitude.Many different wavelengths are produced. Thewaves that resonate have a wavelength that isequal to the length of the tube, or the tube lengthmust be evenly dividable by 1/2 wavelength. Ifyou increase the speed of the spin, the frequencywill increase and you will begin to hear overtones.Kroogah tubes can be purchased from many scien-tific equipment vendors or purchased directy fromany hardware store’s plumbing department.


Ruben’s Tube - 3D30.50 Standing sound wavesare made visible by placing a speaker near a mem-brane covering a tube with evenly spaced holesdrilled along its length. Propane gas is pumpedinto the tube and ignited, creating a row of flamethat reacts to differences in pressure caused by thestanding sound wave.

Hoot Tubes - 3D30.70 Several tubes are avail-able. One Al. tube has wire screens near one end.Hold the tube over the burner so that the screenis in the flame. Heat until the screen glows. Thetube hoots when it is removed from the flame. Thesound stops when the tube is held horizontally.The other tubes only sound when over the flame.

3D32 Air Column Instruments

Organ Pipes - 3D32.10 There are organ pipes ofseveral different lengths available.

Train Whistle - 3D32.901 A toy whistle used toreplicate the sound created by a train whistle

3D40 Resonance in Plates, Bars, Soli

Xylophone - 3D40.10 A small xylophone can beplayed to demonstrate the musical scale.

Singing Rods - 3D40.20 A long aluminum rodwill sing when it is stroked along its length sup-ported at its center. Rub the rod with wax paperprior to use. Hold the rod in the hand between thethumb and forefinger. Also try holding the rod ata point 1/4, 1/6 or 1/8 of its length to excite higher

55

Chladni Plates - 3D40.30 Various size andshaped plates are available. They are attachedto the Pasco mechanical oscillator. Sprinkle someof the fine white sand on the plate.

Musical Goblet - 3D40.50 Rub the edge of the goblet with a wet finger to produce a tone. Varythe water level in the goblet to change the tone.

Shattering Goblet/Beaker - 3D40.55 Thespeaker is tuned to the frequency of the glass us-ing a microphone and an oscilloscope. The turnup the volume until the glass breaks. if you haveextra time, show the glass on a monitor with astrobe light. Most people are surprised by howmuch the glass actually moves before it breaks.

3D46 Tuning Forks

Tuning Forks - 3D46.15 A set of tuning forks isavailable to develop length vs. frequency concepts.

Project a Tuning Fork - 3D46.31 Show the de-tails of motion of a vibrating fork using a stro-boscope and television. Focus the camera on themounted tuning fork. Adjust the stroboscope to256 Hz (same as the tuning fork). Dim lights andturn everything on. There is minimal shadowingdue to the interference of the television. (Televi-sion not shown.)

Thermodynamics

4A THERMAL PROPERTIES OF MATTER

4A10 Thermometry

Mercury Thermometer - 4A10.15 Show variousliquid thermometers.

56 THERMODYNAMICS

Digital Thermometer - 4A10.301 A thermo-couple is attached to a digital voltmeter which issetup to measure temperature using the Celcius orFahrenheit scales.

Thermoelectric Pair - 4A10.31 A piece of nickeland brass have connected at one end. When heatis applied to the junction, a small electric potentialdifference is produced.

4A30 Solid Expansion

Bimetal Strip - 4A30.10 A bimetal strip is brasson one side and steel on the other. When heatedover a Bunsen burner the strip curves toward thesteel side. When cooled in liquid nitrogen, itcurves the other way.

Thermostat Model - 4A30.11 This is an excel-lent demonstration of how thermostats work. Twobimetallic strips are placed so that they are heatedby a heat lamp. As the strips get hot, one ofthe metal strips bend breaking the contact. Thisbreak in contact turns off the lamp. As the lampcools, the metal bends back and contact is madeagain.

Wire Coil Thermostat - 4A30.15 This is an oldhousehold thermostat. As the temperature rises,the wire expands causing the coil to turn. Youcan set the thermostat so that it is barely makingcontact. Then blow warm air on the apparatusand it releases.

4A THERMAL PROPERTIES OF MATTER 57

Ball and Ring - 4A30.20 Try putting the ringaround the ball. At room temperature the ring isslightly larger than the ball. Heat the ball overthe Bunsen burner and try again. You may alsocool the ring in liquid nitrogen. This takes severalminutes.

Sagging Wire - 4A30.60 A variac is attached toa length of Nickel wire with sudden death leads.Turn up the variac until the wire heats up and itwill sag. Pictured are three corks hanging fromthe wire to better see it sag.

4A40 Properties of Materials at Low

Lead Bell - Retired - 4A40.10 Ring bell while itis at room temperature. Pour liquid nitrogen intoinsulated beaker. Let bell sit in the liquid nitrogenuntil untill the boiling subsides somewhat. Ringthe bell again and it will sound something like acow bell.

Smashing Tube - 4A40.30 Pour liquid nitrogeninto the beaker. Put the end of the rubber hoseinto the nitrogen. When the bubbling subsides,take it out and break it with the hammer.

Smashing Flower - 4A40.301 Place the flowerin the liquid nitrogen. After approx. 10 seconds,remove the flower and crush with hand. Make sureto crush the flower over a piece of paper. Thepetals are hard to sweep up.

58 THERMODYNAMICS

Smashing Racquet Ball - 4A40.302 Place a rac-quet ball in the liquid nitrogen for several min-utes. Remove the ball with tongs and either throwagainst the floor or smash with hammer.

4B HEAT AND THE FIRST LAW

4B10 Heat Capacity and Specific Heat

Melting Wax - 4B10.30 This device has fourarms, each of a different common metal, with fourdifferent conductivity ratings. Putting wax tabson the ends of each arm and applying equal heatto the center, by boiling water, allows the class tosee which metal conducts faster. T his demo iseasily used on the overhead.

4B20 Convection

Convection of Liquids - 4B20.10 A closed glasssquare of tubing has an opening at the top. Heatthe tube on one side with a burner. Add a coupleof drops of food coloring to the opening of thetube. The water on the warm side of the tube willstart to rise. This motion is visible by the foodcoloring drops added in the top.

4B30 Conduction

Toilet Seats - 4B30.35 NOTE toilet seats are notavailable, but sheets of metal are. Have studentvolunteers experiment to see if aluminum makes agood seat. All materials will be the same temper-ature.

4B HEAT AND THE FIRST LAW 59

4B50 Heat Transfer Applications

Water Balloon Heat Capacity - 4B50.25 Filla balloon with air, and it is popped by the candleflame!!! Fill another balloon with water, and itdoesn’t pop in the flame.

Hand in LN2 - Leidenfrost Effect - 4B50.32Pouring liquid nitrogen over your hand allows youto demonstrate the Leidenfrost effect.

Reverse Leidenfrost Effect - 4B50.40 Place asteel ball in liquid nitrogen observing the initialleyden frost effect. Now place the ball in the flameof a bunsen burner. The reverse leyden frost effectcauses the ball to be covered by frost while in theflame.

4B60 Mechanical Equivalent of Heat

Dropping Lead Shot - 4B60.10 Stick the temperature probe into the bag of lead shot to find itsinitial temperature. Drop the bag from the height of two meters 10-20 times. Take the temperatureof the lead again. The temperature should rise 2-3 degrees Celsius.

60 THERMODYNAMICS

Heat from Colliding Steel Spheres - 4B60.15Smash two steel spheres together with a piece ofpaper in between. Heat from the collision willburn a hole in the paper.

Combustion Cannon - 4B60.701 a bottle with a rubber stopper has 2 screws stuck through thesides. the bottle is filled with a very small amount of methanol, stopped and shaken, then held neara Van De Graf generator. the resulting spark across the screws will cause the methanol vapor toexplode, propelling the rubber stopper.note: same demo as 5A50.301

Piezoelectric Popper - 4B60.702 A small film canister is filled with a few (about 2 or 3) dropsof methanol, sealed, and then sparked with a piezoelectric igniter, causing the methanol vapor tocombust and shoot the body of the film canister outward.note: same demo as 5E60.211

4B70 Adiabatic Processes

Fire Syringe - 4B70.10 A thick-walled test tubeis protected by a clear plastic tube and a rubberstopper. A wisp of cotton fiber is at the bottom ofthe tube. Set the stopper on the table and pushthe piston down AS QUICKLY AS POSSIBLE.You may wish to practice. The cotton will ignite.The flash is visible to the whole classroom.

Expansion Cloud Chamber - 4B70.20 A rub-ber bulb fits into the top of a gallon jug, whichcontains a small amount of water. Slosh the wateraround in the jug to saturate the air with watervapor. Drop a lighted match into the jug and putthe bulb on the top. Squeeze and release the bulbrapidly to create the cloud.

Gas Law Apparatus - 4B70.37 Use this appara-tus to test out the relationship between pressure,volume and temperature of an ideal gas.

4C CHANGE OF STATE 61

4C CHANGE OF STATE

4C20 Phase Changes: Liquid-Solid

Freezing Liquid Nitrogen - 4C20.40 A beakercontains liquid nitrogen. Pump out the bell jar tofreeze the liquid nitrogen. The freezing tempera-ture is about 68 degrees Kelvin, about ten degreesbelow the liquefying temperature of 77. Only thesurface may freeze and then break as pumping con-tinues.

4C30 Phase Changes: Liquid-Gas

Boiling by Cooling - 4C30.10 Heat water inFranklin flask until it boils. Cork the flask andremove from the flame. Invert and place ice cubesin the special concave bottom. As the pressurelowers, the water starts boiling again.

Burst a Balloon - 4C30.35 The evaporating liquid nitrogen expands the balloon and pops it.

Exploding Racquetball Can - 4C30.351 Just cover the bottom of the can with liquid nitrogen.When the boiling slows, put the lid on. It pops back off and shoots about 1 meter into the air.

Liquid Nitrogen Canon - 4C30.352 Place a tube of LN2 in the steel pipe. Using your hand, smasha cork on the end. Now shake the tube and the cork will fly off. Be careful not to point the cork atyourself or students!

Liquid Nitrogen Hovercraft - 4C30.353 A bottle is filled with liquid nitrogen and plugged witha rubber stopper. Nitrogen gas then escapes through a small hole in flat metal plate, causing thebottle to hover on a cushion of nitrogen gas.

4C31 Cooling by Evaporation

Drinking Bird - 4C31.30 Soak the bird’s headin the water and let him “drink”. As the waterevaporates off of the birds head, it cools. Thiscaused the water to expand into the head of thebird, throwing it off balance and dunking its headin the water again. The process repeats.

62 THERMODYNAMICS

4C33 Vapor Pressure

Palm Glass - 4C33.50 The palm glass demon-strates the contrasting effects of heat and gravityon a volatile liquid. It consists of two glass bulbsconnected by a glass tube. The glass is partiallyfilled with a colored liquid, such as methylene chlo-ride, having a low vapor point. The air in thetube has been partially evacuated. The fluid withthe low vapor point will evaporate with a rela-tively low input of thermal energy. Once the fluidreaches the upper bulb, it will cool and return tothe liquid state. After it flows back down to thehand held bulb, the process repeats.

4C40 Sublimation

Carbon Dioxide - 4C40.10 You get a piece of dry ice in a glass dish.

4C50 Critical Point

Critical Opalescence - 4C50.20 A sealed cham-ber contains a solution that when heated with aheat gun is brought to the critical point. Thedemonstration is shown using the videoflex cameraand a television monitor.

4D KINETIC THEORY

4D20 Mean Free Path

Crookes Radiometer - 4D20.10 This radiometerspins in the opposite direction from what theorypredicts; the white sides move forward. Turn onthe light and watch it spin.

4E GAS LAW 63

4D30 Kinetic Motion

Molecular Motion Demonstrator - 4D30.10The molecules of the gas are represented by 51steel ball bearings. In the kinetic theory of gasses,as a gas is heated, the random kinetic energy ofthe molecules increases, increasing the pressureof the gas on the sides of the container. In thisdemonstration, kinetic energy is imparted to theball bearings by a vibrating plunger which fits intoa slot in the bottom of the container.

4E GAS LAW

4E10 Constant Pressure

Balloon in Liquid Nitrogen - 4E10.20 An air-filled balloon sits in a dish. Pour liquid nitrogenover the balloon and watch it shrink. Take theballoon out and it “blows” back up.

4E20 Constant Temperature

Balloon in a Vacuum - 4E20.40 A partiallyblown up balloon is inside a sealed bell jar. Turnon the vacuum pump. The balloon “blows” up.

Marshmallow Man - 4E20.401 A stick figure iscovered with marshmallows is placed in a bell jar.Turn on the vacuum pump and the marshmallowman expands to about twice his original size.

64 THERMODYNAMICS

Shaving Cream in a Vacuum - 4E20.402 Placea small amount of gel shaving cream into a tallbeaker inside of a bell jar. When the vacuumpump is turned on, the shaving cream will riseup fast. Be careful not to let the shaving creamoverflow.

4E30 Constant Volume

Constant Volume Bulb - 4E30.10 The gaugemeasures the pressure in the sealed sphere inpounds per square inch. Atmospheric pressure is14.7 lbs/in2. Read the pressure when the bulb isimmersed in boiling water and ice water.

4F ENTROPY AND THE SECOND LAW

4F10 Entropy

Unmixing Demo - 4F10.10 The area betweencoaxial cylinders is filled with a Newtonian fluid,Glycerine, and a suitable tracer, food color mixedwith Glycerine. When the inner cylinder is ro-tated, the tracer appears to be mixed but is dis-tributed in a fine one armed spiral sheet. Revers-ing the direction of inner cylinder rotation willcause the original tracer pattern to reappear.

4F30 Heat Cycles

Stirling Engine - 4F30.10 Light the burner. Ifthe engine is cold it takes several minutes before itis hot enough to run. We can light the burner justbefore the beginning of class. Start the engine byturning the flywheel in the direction indicated onthe cutaway model.

65

The Visible Stirling Engine - 4F30.101 Theengine runs off of the temperature difference inthe two metal plates. The expanding warm airand the compressing cold air by the opposite platekeep the foam pad in constant motion between theplates. This thermodynamic tug-o-war providesthe energy to run the engine.

Jensen Steam Engine - 4F30.20 The steam en-gine runs on steam pressure made by heating wa-ter in a boiler the same way water is boiled in atea kettle. The first practical steam engines werebuilt about 1700 and were used to pump water.Over the years steam engines where built to op-erate many types of equipment from autos, suchas the Stanley Steamer, to farm tractors, trainsand ships. The steam engine reached its peak usearound 1900.

Memory Wire - 4F30.601 A wire made out ofnickel and titanium, called nitinol, can be benteasily when cooled down and straightens force-fully when heated. It “remembers” a shape whenmolded while held in a flame. Straighten the wirein ice water, then hold in the flame again. It willgo back to the shape you molded it to hold. Canbe used to discuss various applications includingnitinol engines and deployment of satellite anten-nas.

Electricity and Magnetism

5A ELECTROSTATICS

5A10 Producing Static Charge

Rods and Fur with Electroscope - 5A10.10PVC and/or clear plastic rods are rubbed withdifferent materials to build up static charges andshow static electric fields.

66 ELECTRICITY AND MAGNETISM

Electrophorus - 5A10.20 Pronounced “ee-lek-TRAH-for-us”, this device works much like theRods and Fur (PIRA# 5A.10.10) demo as a wayof creating (and moving) static charges.

5A20 Coulomb’s Law

Rods and Pivot - 5A20.10 Rub both ends of arod and center it on the pivot. Rub the PVC rod(negative charge) with the fur or the plastic rod(positive charge) with the plastic sheet. Rub oneend of a second rod and hold its charged end nearthe end of the rod on the pivot.

Pith Balls - 5A20.20 Charge pith balls and viewthe separation. This only works on very dry days,usually in January or February. We recommendusing rods and Pivot.

Beer Can Pith Balls - 5A20.28 Charge the beercans by “scraping” the charge off the rod. (Chargewill not flow on the non-conducting rod.) Thisdemonstration only works on very dry days, usu-ally in January or February. We recommend usingRods and Fur

5A40 Induced Charge

Electroscope Charging By Induction -5A40.15 Touch the electroscope and bring acharged rod close. If the charged rod is nega-tive, electrons from the electroscope will flow ontoyour body. Now remove your hand and then movethe charged rod away. The electroscope will beleft with a deficit of electrons giving it a positivecharge. This can be confirmed by bringing thenegative rod back close to the electroscope andwatch the deflection go away.

5A ELECTROSTATICS 67

Charge Propelled Soda Can - 5A40.20 Set anempty soda can on the table so the open end facesthe students. Pull the can forward with inducedcharge. Switch to the oppositely charged rod andrepeat. The can is attracted to the rod no matterwhat the charge is.

2 X 4 Attraction - 5A40.30 A 2 x 4 is balancedon a large watch glass. Hold a charged rod nearthe side of one end of the 2 x 4.

Metal Rod Attraction - 5A40.35 Place themetal rod on the pivot. Rub the PVC rod withfur (negative) and attract the rod. Rub the clearrod with plastic (positive) and attract the rod.

5A50 Electrostatic MachinesWimshurst Machine - 5A50.10 Two circulardiscs, made of Plexiglass and with a diameter of31cm, are mounted parallel with one another andwith a short distance apart on a horizontal axis.The axis rests on two struts which are attachedto the base plate. Each disc is connected indepen-dently to the drive shaft via belts and pulleys. Oneof the belts is crossed and as result the discs rotatein opposite directions when the crank is turned.The external surfaces around the perimeters ofboth discs are covered with metal foil stripes. Infront of each disc a conductor arm is mounted di-agonally, which can be rotated on their axes andwhich are fitted with metal brushes that drag overthe metal foil stripes of the discs. The front endof the axle is extended and connected with the in-sulating bar by means of a knurled screw. Thecharge is collected from the two discs by metalbrushes located at the end of the insulating bar.These brushes are connected to the two ball endedelectrode rods and by means of the lever rods tothe two Leyden jars. The Leyden jars of glass arecoated with metal foil outside and inside. the twoterminals are connected to the outer coating of theLeyden jars and are used to draw off an AC volt-age. Regularly the terminals are short circuited toenable a DC voltage to be drawn off. The maxi-mal spark length obtainable with this machine isabout 120mm. The short circuit current is approx-imately 30 microamps.


FunFlyStick - 5A50.100 The FunFlyStick is abattery-powered static generator that creates astrong positive electrostatic charge. When one ofthe small Mylar samples touches the stick, it be-comes positively charged so that it expands andlevitates above the stick.

Van De Graaff Generator - 5A50.30 Use toshow sparks from the generator to the groundedsphere.

Combustion Cannon - 5A50.301 a bottle with a rubber stopper has 2 screws stuck through thesides. the bottle is filled with a very small amount of methanol, stopped and shaken, then held neara Van De Graf generator. the resulting spark across the screws will cause the methanol vapor toexplode, propelling the rubber stopper.note: same demo as 4B50.701

5B ELECTRIC FIELDS AND POTENTIAL

5B10 Electric Field

Hair on End - 5B10.10 Remove pointed metalitems such as keys and microphones. Stand onthe insulated stool. With the variable controlfully counterclockwise, turn the power on. Holdthe pointed probe against the sphere while turn-ing up the motor. Place your other hand on thesphere BEFORE removing the probe. DO NOTREMOVE YOUR HAND and stay away from any-thing metal. Allow yourself to charge up. Fine,clean, dry hair stands on end best. Try pointingat a student or the electrified strings.

Van De Graaff with Streamers - 5B10.15 Rib-bons are attached to the Van de Graaff sphere.Turn on the Van de Graaff generator. The rib-bons will usually stick to the conducting sphere.Use the ungrounded, pointed probe to lift themoff. The ribbons will arrange themselves so thatthey follow the field lines.

5B ELECTRIC FIELDS AND POTENTIAL 69

Van de Graaff with Jumping Pie Plates -5B10.20 Stacked aluminum pie plates will jumpoff the Van De Graaff one at the time. Try to getthe students to explain why.

Van De Graaff with Styrofoam Peanuts -5B10.25 Set a Styrofoam bucket full of Styrofoampeanuts on the Van de Graaff generator. Whenyou turn it on the peanuts fly out field liner.

Electrified Strings - 5B10.26 Nylon strings hangfrom a rod. Wrap the cellophane around thestrings and pull downward. The charged stringscan be discharged by the piezoelectric gun or bypointing at the strings when you are charged bythe Van de Graaff generator.

Electrostatic Ping Pong - 5B10.35 A ping pongball suspended by a string bounces back and forthbetween two charged plates.

Electric Field Lines - 5B10.40 View electricfield lines between charged electrodes. 5 elec-trode plates with different charge configurationsare available.


EM Field Software - 5B10.990 ”This fully interactive software tool encourages rapid, qualitativeexploration of electric and magnetic fields - a notoriously abstract topic - and will help your studentsgain an intuitive understanding of force fields, Gauss’s law, Ampere’s law, and the concept of flux.”

5B20 Gauss’ Law

Faraday’s Ice Pail - 5B20.10 Place a charge onthe sphere. Touch the inside of the pail with theproof plane. Touch the plane to the Pasco Elec-trometer and show no charge is present. Nowtouch the outside of the pail and then the elec-trometer. The meter on the overhead will deflectand hold the charge.

Faraday’s Ice Pail (large) - 5B20.101 When thewashtub is charged, excess charges will move tothe outside of the washtub, and the inside of thewashtub will remain neutral.

5B30 Electrostatic Potential

Lightning Plate - 5B30.261 Hang the lightningplate on the insulating stand and connect each endto either the Van De Graaff or Wimshurst electro-static generators. When the generator is turnedon, sparks will begin to jump the gaps (at thesame time) as the generator is grounded.Things to note about this demonstration:1) The sparks always follow the shortest path. 2)Spark brightness is uniform for all gap widths.The total of all the spark gaps is about 1.1 inches(2.8mm) and will require a minium voltage of25,000 to 30,000 volts.

Van de Graaff with Ball and Point - 5B30.35A conducting ball and a point are grounded tothe Van de Graaff. Turn on the Van de Graaffand alternately hold the ball and point near thelarge sphere. Hold the ball near the sphere andthen bring the point near to stop the sparking.

5C CAPACITANCE 71

Electric Wind - 5B30.40 The capacitor used forthe ’Electrostatic Ping Pong’ demo is connectedto the Dirod machine. A candle is placed on astand in between the two plates. While the DirodMachine is running, the flame will lay down.

Pinwheel - 5B30.50 The pin wheel spins ascharges jump off the points.

Ignition Bottle - 5B30.91

5C CAPACITANCE

5C10 Capacitors

Sample Capacitors - 5C10.10 You get a box of capacitors and capacitor parts to show and tell.

Parallel Plate Capacitor - 5C10.20 An electroscope is connected to the parallel plate capacitorto show how charge behaves on the capacitor.When the capacitor plates are close together, its capacitance increases and more charge is presenton the capacitor plates. This means there is less charge on the electroscope and the metal indicatortends to be vertical.When the capacitor plates are moved farther apart, its capacitance decreases and less charge ispresent on the capacitor plates. This means that there is more charge on the electroscope and themetal indicator moves away from the vertical.

5C20 Dielectric

Capacitor with Dielectrics - 5C20.10 An electroscope is connected to a parallel plate capacitorto show how capacitance increases when a dielectric is inserted between the capacitor plates.When the dielectric is inserted, the dielectric polarizes and attracts more charge to the capacitorplates (increasing its capacitance). This effect can be seen by the fact that electroscope shows thepresence of less charge, indicating that more charge is now on the capacitor plates.When the dielectric is removed, its capacitance decreases and some charge leaves the capacitor andgoes back to the electroscope.

Dissectible Condenser - 5C20.30 Charge the condenser with the Dirod Generator. Use the wandto disconnect the charging wire from the stem of the condenser. Lift out the inner section with thewand. Lift out the glass by hand. Pass the parts around. Reassemble and draw a spark.


5C30 Energy Stored in a Capacitor

Leyden Jar with Wimshurst machine - 5C30.10 A Leyden Jar is coated on the inside and outwith a conducting material. The conductors are isolated from each other. Electrical connectionsare made to the from each surface to an individual arm on the Wimshurst machine by contact bars.When the Leyden jars are connected to the Wimshust machine, the sparks are much more intenseand less frequent than they are when the Leyden jar is not connected.

Discharge a Capacitor - 5C30.211 A bank of6 5600 microfarad capacitors is charged up to 20volts using a power supply, or, upon request, up to45 volts using a bank of 9 volt batteries. Dischargewith Aluminum bar to show the large spark anddiscuss the energy stored inside a capacitor.

Charge and Discharge a Capacitor - 5C30.30 Turn on the power supply to charge the capacitor.Turn off the power and disconnect the power supply. To discharge capacitor, connect to the lightbulb only.

Lifting a Weight with a Capacitor - 5C30.35Charge a 1 Farad capacitor to 5V. Connect thecharged capacitor to a geared motor. The motorwill lift a 50 gram mass.

Series and Parallel Capacitors - 5C30.42

5D RESISTANCE

5D10 Resistance CharacteristicsResistor Assortment - 5D10.10 Resistors of different values and sizes are available to pass aroundthe class.

Resistance Model - 5D10.40 Small pegs cover an inclined plane. Roll the small plastic balls downthe inclined plane to simulate the motion of electrons in a conductor.

5E ELECTROMOTIVE FORCE AND CURRENT 73

5D20 Resistivity and Temperature

Coil in Liquid Nitrogen - 5D20.10 A coil ofnickel wire is lowered into liquid nitrogen. Theresistance of the coil is measured with a digitalmultimeter. It drops from around 3 ohms to 1.2ohms. The digital multimeter is displayed on atelevision screen using the VideoFlex camera.

Current in Lamp Circuit - 5D20.30 Plot theVoltage and Current for a circuit lighting a 100watt lamp. Voltage is supplied from a variac.

5D40 Conduction in GasesJacob’s Ladder - 5D40.10 This is a step up transformer. CAUTION: LETHAL VOLTAGE. Turnon the power and the discharge will travel up the wires. The distance between the wires is the criticaladjustment. The wires should not be moving. This does not work well on humid days. Unplug thisafter use.

5E ELECTROMOTIVE FORCE AND CURRENT

5E40 Cells and BatteriesCharge From a 10 kV Power Supply -5E40.501 A wire with a series of resistors is con-nected to a 10 kV DC power supply. When thepower supply is turned on, one end of the wire hasan electric potential of -5 kV and a negative netcharge, the other end has a potential of +5 kVand a positive net charge, and the middle has apotential of 0 V and zero net charge.The net charge can be shown by hanging a pieceof foil near the wire. When the foil is neutral, itwill be attracted to the two charged ends of thewire. When the foil touches one end of the wire,the foil then becomes charged and is repelled fromthat end of the wire, and is attracted to the otherend of the wire.

5E60 Piezoelectricity

Piezoelectric Popper - 5E60.211 A small film canister is filled with a few (about 2 or 3) dropsof methanol, sealed, and then sparked with a piezoelectric igniter, causing the methanol vapor tocombust and shoot the body of the film canister outward.note: same demo as 4B60.702


5F DC CIRCUITS

5F20 Circuit Analysis

Kirchhoff’s Voltage Law - 5F20.10 A 9 voltbattery and two resisters are wired in series. Mea-sure the voltage accross the battery and the tworesisters and show that the sum of the voltages iszero. Please turn off power when demo is finished.

Series and Parallel Light Bulbs - 5 bulbs Large - 5F20.50 Adjust the switches to have all thelamps in series or parallelShow that while in parallel that any lamp can be turned off without changing the brightness of theothers.Show that as you add more lamps in series, the brightness of each lessens. Also if you remove alamp in the series circuit, they all go out.

Series and Parallel Light Bulbs - Two Bulbs - 5F20.501 Two lamps can be connected in seriesor parallel by throwing a switch.

Series and Parallel Light Bulbs - 5 Bulb Small - 5F20.502 Adjust the switches to have all thelamps in series or parallel

5F30 RC Circuits

E&M Desktop Experiment Kit - 5F30.90

5G MAGNETIC MATERIALS

5G10 Magnets

Magnet Assortment - 5G10.10 Several bar,horseshoe and refrigerator magnets are suppliedin a box. These magnets can be passed aroundfor students to investigate and erase their creditcards.

Lodestone - 5G10.15 This ferromagnetic ore sam-ple contains mostly ferric oxide. Can be used witha overhead compass to show natural magnetism.

5G MAGNETIC MATERIALS 75

Which is a Magnet? - 5G10.30 Two similar barsof iron are supplied. One is magnetized and theother is not. How do you tell them apart? Bringthe end of the non-magnetized bar to the center ofthe magnet and there is no attraction. Now bringthe end of the magnet to the non-magnet and liftit up.

5G20 Magnet Domains & Magnetization

Iron Filings Domain - 5G20.27 Stroke thissealed tube with a magnet and its iron filings lineup, temporarily magnetized. You can then showthe tube is a magnet by its effect on a compassneedle. Shake the tube and the filings fall out ofline, demagnetized.Magnetic Induction - 5G20.46 A large soft iron bar that is held in contact with a large horse shoemagnet becomes magnetized itself. You can use this combination to pick up a large number of nails.When the large soft iron bar is removed from the magnet, the nails fall.

Electromagnet - 5G20.70 This compact electro-magnet is able to lift up to 200 pounds with onlyone or two 1 1/2 volt D cell batteries as a powersource. This is due to precision machining of theflat surfaces (core and yoke). Compare it to cranesthat can lift automobiles around a junk yard.

Homemade Electromagnet - 5G20.701 Ahomemade electromagnet that consists of a boltand wire coiled around it will pick up a collectionof small nails. Larger professional electromagnetsare available on request.

5G30 Paramagnetism and Diamagnetism

Paramagnetism of Liquid Oxygen - 5G30.20Liquid oxygen sticks to the poles of a strong mag-net. The liquid oxygen is created using an alu-minum cone and liquid nitrogen. The liquid oxy-gen condenses on the aluminum foil and drops be-tween the magnetic poles. A VideoFlex camerais used to display the demonstration on the largetelevision or project it on the screen.


5G50 Temperature and Magnetism

Curie Temperature - 5G50.10 A steel paper clipis suspended by a magnet. Heat the paper clipwith the gas torch until it drops off of the mag-net. When the paper clip cools, it will again beattracted to the magnet.Physics: At the Curie Temperature, the ferromag-netic material becomes paramagnetic.

Meissner Effect - 5G50.50 Place magnet onwarm disk to show how nothing happens, then re-move. Add liquid nitrogen to the Styrofoam con-tainer holding the superconducting disk. Whenthe boiling stops. Use the plastic tweezers to placeone of the magnets on the disk.

Superconductivity - 5G50.501 This demonstra-tion includes a high temperature superconductingdisk consisting of Yttrium, barium, copper andoxygen. It becomes superconducting below 90 K.The disk is attached to an absorbent material thatinsulates and holds liquid nitrogen to keep the su-perconductor cool longer.A magnetic track is also included. The magnetsare arranged so that the magnetic poles are allaligned one way in the front of the track, and inthe opposite way in the back of the track. Thiscreates a magnetic field that is generally uniformalong the length of the track, but it is not uniformoff the sides or up and down.One more device that is included is a block of mag-nets with their polarities all alternating.The expulsion of magnetic field from a supercon-ductor is an intrinsic property of any supercon-ductor. Below a certain magnetic field the super-conductor expels nearly all magnetic flux by cir-culating current near its surface.Flux Pinning In some cases the magnetic flux be-comes locked or “pinned” inside a superconductor.Flux pinning is desirable in high-temperature ce-ramic superconductors to prevent flux movementswhich introduce a resistance and dissipate energy.The pinning is achieved through defects in thecrystalline structure of the superconductor usuallyresulting from grain boundaries or impurities.

5H MAGNETIC FIELDS AND FORCES 77

5H MAGNETIC FIELDS AND FORCES

5H10 Magnetic Fields

Magnetic Paper Clip Arrow - 5H10.10 A Smallmetal arrow can be held near a large magnet toshow the direction of the magnetic field.

Magneto-Rheological (MR) Fluid - 5H10.100Lord Engineerings description of the fluid con-tent:MR fluid consists of 20-40 percent by volumeof relatively pure, 3-10 micron diameter iron parti-cles, suspended in a carrier liquid such as mineraloil, synthetic oil, water or glycol.The fluid becomes solid in miliseconds when intro-duced to a magnetic field.

Compass - 5H10.11 A compass is available foruse on the overhead projector. Place a wire nextto the compass and pulse a current through it.The needle will deflect.

Dip Needle - 5H10.15 A large compass can beturned on its side to show the magnetic field linesof the Earth.

Oersted’s Effect - Apparatus - 5H10.20 Thisapparatus demonstrates the magnetic field createdby a current in a wire. The compass needle in thecenter of the apparatus will align itself with thenet magnetic field present.


Oersted’s Effect - Simple Wire with Compass - 5H10.201 Demonstrate the magnetic fieldinduced in a current carrying wire.

Magnet and Iron Filings - 5H10.30 Sprinkleiron filings on the Plexiglass plate that is placedover the bar magnet. Tap the Plexiglass to en-courage alignment.

Iron Filings in Oil - 5H10.31 Iron filings sus-pended in oil react to a magnet when put in thecenter of the container. The filings generally showthe magnetic field lines.

5H15 Fields and Currents

Field of Wire and Iron Filings - 5H15.10Sprinkle iron filings on the Plexiglass. Hold downthe tap switch briefly while tapping the Plexiglassto encourage alignment.

5H MAGNETIC FIELDS AND FORCES 79

Right-Hand-Rule Prop - 5H15.131 Provides avisual representation of the right hand rule for amagnetic field from a current on a straight wire.The hoop represents a B-field line around astraight wire. The blue arrow can be clipped to thehoop to represent the B-field at a specific point.

Solenoid and Iron Filings - 5H15.40 Sprinkleiron filings on the Plexiglass. Hold down the tapswitch briefly while tapping the Plexiglass to en-courage alignment.

Torroid and Iron Filings - 5H15.50 Sprinkleiron filings on the Plexiglass. Hold down the tapswitch briefly while tapping the Plexiglass to en-courage alignment.

5H20 Forces on Magnets

Magnets and Pivot - 5H20.10 One magnet iscentered on a pivot. Hold one end of the secondmagnet near one end of the magnet on the pivot.Repeat with the opposite end.


Levitation Magnets - 5H20.20 6 ring magnetsare placed on a small wooden dowel with like polesfacing each other.

Levitron - 5H20.22 With this device, a magnettop is spun and suspended above a larger mag-net. The magnet fields are in opposition, so theyrepel, and the gyroscopic motion of the magnetictop keeps it “up right” so its magnetic poles donot flip.The levitron takes a good deal of practice, so besure to practice it well ahead of your lecture.

5H25 Magnet/Electromagnet Interact.

Magnetic Field from a Coil - 5H25.10 A barmagnet is placed on a rotating stand near a coil.A DC power supply is then switched on, creatinga current in the coil and therefore a magnetic field.The bar magnet then rotates so that its magneticfield is aligned with the coil’s magnetic field.

5H30 Force on Moving Charges

Cathode Ray Tube - 5H30.10 Deflect the beamof the CRT by holding a permanent magnet nearthe edge of the tube. If the beam disappears youare holding the magnet too close.

Crookes Tube - 5H30.15 An electron Beampasses through a slit and makes a green line onthe fluorescent screen. Bring a magnet close toshow deflection. The room must be very dark forthe class to see this.

5H40 Force on Current in WiresForce Between Parallel Wires - 5H40.10 Two parallel wires are allowed to rotate freely. Bychanging the direction of the current in either wire, the wires either attract each other or repel.

5J INDUCTANCE 81

Jumping Wire - 5H40.30 A long wire is sus-pended in the field of a permanent magnet!!! Closethe switch. The wire jumps out of the magnet.This experiment demonstrates the force on a cur-rent carrying wire in a magnetic field. The forceis determined by F=ILxB, where the direction isdetermined by LxB and the magnitude by ILB-sin(theta).WARNING: Do not leave current running throughthe wire, or the solder will melt.

Levitating Foil - 5H40.34 Horseshoe magnets arearranged in a line over a strip of aluminum foil. ADC current is run through the foil and the foil islifted off the table by the force of the interactivefields.

5H50 Torques on Coils

Torque on a Coil - 5H50.20 The force of theelectromagnetic interaction between a coil and amagnet can be shown with this demonstration. Alarge coil is suspended over a powerful magnet.The demonstrator switches on a current throughthe coil and the class observes a rotation of thecoil. This rotation aligns the magnetic field gen-erated by the electric current with the magneticfield created by the magnet.

5J INDUCTANCE

5J10 Self Inductance

Inductor Assortment - 5J10.10 A box of inductors can be passed around the class.

Back EMF - 5J10.20 Close the switch to the in-ductor and turn on the DC power supply (Full16V DC). Open the switch and the lamp will flash.The light and the inductor are connected in par-allel. The power supply and the switch are thenin series with the bulb and the inductor.


5K ELECTROMAGNETIC INDUCTION

5K10 Induced Currents and Forces

Move Wire in Horseshoe Magnet - 5K10.15Move a single wire in and out of the horseshoemagnet. Make loops of 2, 3, 4, etc. and repeat.Observe deflection on galvanometer.Video of a single wire:Video of multiple wires:

Induction Coil with Magnet - 5K10.20 Movethe magnet in and out of the coil connected to thegalvanometer.

Multiple Coils with Magnet - 5K10.201 A Galvanometer is connected to three solenoids with20, 40, and 80 turns.

Induction Coil with Power Supply - 5K10.30Close and open the switch and observe deflectionon a galvanometer. Solid iron cores are available.

Induction Coils with Radio - 5K10.34 A coilis hooked to the speaker outputs of a small radio.Another coil is hooked to an amplifier and speaker.Turn the radio on and bring the coils together.

5K ELECTROMAGNETIC INDUCTION 83

5K20 Eddy Currents

Eddy Current Pendulum - 5K20.10 Displacethe pendulum and let it swing. It stops dead be-tween the poles. Repeat with the slotted plate andslit ring.The following video shows all three pendulums inaction.

Eddy Current Brake - 5K20.22 Bring the horse-shoe magnet up to the free spinning aluminumdisc. The disk will slow down very quickly.

Magnets and Tubes - 5K20.25 Drop the magnetdown the tube. The tube has a slit cut in it allow-ing the students to see the magnet falling. It takesseveral seconds for the magnet to fall through thetube. Please try to catch the magnet. They arebrittle. Repeat with nonmagnet.

Faraday Repulsion Coil - 5K20.26 A lightaluminum ring is suspended. Bring a largeneodymium magnet close to the ring and it willbe repelled. Move the magnet away and the ringwill try to follow. Repeat the experiment movingthe magnet fast and then slow.

Jumping Ring - 5K20.30 Two aluminum rings can be placed around the core of a coil. One ringhas a slit and one is solid. With a ring in place, turn on the switch. The solid ring jumps and theslotted ring does not.

Eddy Current Levitator - 5K20.40 A magnetbalanced by two strings is allowed to float over aspinning aluminum disc.


Arago’s disk - 5K20.42 A bar magnet is sus-pended above an aluminum disk. When the diskstarts spinning, it will ’drag’ the magnet and causeit to start spinning in the same direction.

5K30 Transformers

Sample Transformers - 5K30.25 Two sampletransformers can be shown to the class. One isdesigned for mounting and the other is the plug-in type. The plug-in transformer has been openedto show the coil windings inside.

Small Transformer - 5K30.251 A plug in Ataripower supply has been opened so the students canview the coils.

Vertical Transformer - 5K30.30 Turn on thepower to the large coil (primary). Put the smallcoil (secondary) around the core on top of the pri-mary to light the lamp.

Reaction of Secondary on Primary - 5K30.60A light bulb is in series with the primary of a trans-former. As the resistance across the secondary ofthe transformer is increased, the current throughthe primary decreases. The amount of currentflowing through the primary is illustrated the in-tensity of light bulb and in this case it does notglow as brightly.

5K ELECTROMAGNETIC INDUCTION 85

5K40 Motors and Generators

Motor and GeneratorDemonstration Model - 5K40.10 The compo-nents of the model are mounted in a rectangularsteel frame about 38cm high and 48cm wide. Themain components of the model are two field coils,two armature coils, and a commutator.All coils are of the samesize and are wound withinsulated copper wire. To help the student distin-quish between the north and south magnetic poles,one field coil and one armature coil are paintedblue, the other two coils are painted orange.The armature, well-balanced on the frame, ismounted between low-friction bearings at the baseand thus revolves smoothly. The model can be op-erated on less than 6VDC. A 6V latern battery orthree or four 1.5V batteries connected in series aresufficient for any operation, although any 6VDCpower supply will work.

St. Louis Motor - 5K40.101 Study the functionsof the basic parts of electric motors and generatorsand to explain the observed phenomena in termsof fundamental physical laws and principles.

Homemade DC Motor - 5K40.102 Close theswitch to start the motor. If the coil does notrotate, turn the shaft by hand to get it started.


Homemade Homopolar Motor - 5K40.103 Ho-mopolar motors are so named because the electriccurrent does not change direction as the motor ro-tates. As a result, a commutator is not needed,which simplifies the design and the discussion.There are two designs available that can be seenin the pictures. The standing design (shown in thefirst two pictures) and the hanging design (shownin the third picture). In the standing design, thebattery and magnet stand motionless, and thewire revolves around them as a result of the mag-netic forces on the current in the wire.In the hanging design (third picture), the batteryand wire are held, and the magnet rotates as a re-sult of the magnetic forces on the current throughthe magnet.

Eternity Flashlight - 5K40.28 An internal ca-pacitor in this flashlight is charged by shaking theflashlight back and forth (with moderate force).When this is done, an internal magnetic is forcedback and forth through a coil. The induced cur-rent in the coil then powers the capacitor. A recti-fier circuit is used to convert the AC current fromthe coil to DC before it is connected to the capac-itor.

Coupled motor/generators - 5K40.45 Twosmall permanent magnet DC motor/generatorsare provided. These are hand-cranked devices thatcan be used to power a small light bulb, or theycan be coupled together so that one is the genera-tor and the other one is the motor. When coupledtogether, crank one by hand, and the handle onthe other one will then spin.

Hand Crank Generator - 5K40.80 Crank untilthe lamp shines.

5L AC CIRCUITS 87

Hank Cranked Motor/Generator - 5K40.801This device can either be ran as a DC motor orAC/DC Generator.

5L AC CIRCUITS

5L20 LCR Circuits - AC

RLC - 5L20.20 Turn on the power. Raise andlower the inductor core. The light bulb brightnessindicates the resonance point.

5L30 Filters and Rectifiers

Blinky Whirligig - 5L30.20 The LED is only litwhen current in flowing in the proper direction.AC is applied so the LED is only lit every half acycle. This can be shown by spinning the LED.

5N ELECTROMAGNETIC RADIATION

5N10 Transmission Lines and AntennasTransmission Lines - 5N10.15 One light bulbis connected directly to a coil with 100 ft of tele-phone wire; it glows brightly. Another light bulbis connected to a transformer where the voltageis stepped down from 110 V to 24 V, so the cur-rent increases. The current runs through the 100ft of wire, where the greater current causes en-ergy losses. The current then goes through an-other transformer, where the voltage is steppedup again and the current decreases, so the lightbulb glows dimmer than the first. This shows howpower companies should step their voltage up todecrease the current through the wires and de-crease energy loss.

Radiation and Polarization - Decimeter Wave Transmitter - 5N10.61 A loop dipole antennatransmits a signal at 433.92 MHz (UHF). A rod dipole antenna with a light bulb is then used tocapture the signal and light a light bulb.The signal can only be received when the antenna is in the correct orientation. Aluminum foilpolarizers can be used to cancel the signal.

88 OPTICS

5N20 Tesla Coil

Tesla Coil with Fluorescent Lamp - 5N20.50Hold a fluorescent lamp and let a Tesla coil arc toit. The lamp will glow brightly without harmingyou.

Electrodeless Discharge - 5N20.55 Hold a bulb of neon gas at low pressure near a Tesla coil andshow that electrodes are not necessary for the maintenance of discharge.

Tesla and Light Bulb - 5N20.551 Bring theTesla coil to the base of a standard clear house-hold lamp.

5N30 Electromagnetic Spectrum

Projected Spectrum with Prism - 5N30.10Turn on the light to project white light spectraonto the screen.

Optics

6A GEOMETRICAL OPTICS

6A10 Reflection From Flat Surfaces

Blackboard Optics - Plane Mirror - 6A10.10Show reflections from plane mirrors

6A GEOMETRICAL OPTICS 89

Laser and Flat Mirror - 6A10.15 A laser isaimed toward a flat mirror. Vary the incident an-gle by rotating the laser. Use chalk dust or liquidnitrogen to make the laser beam visible.

Diffuse Aluminum Plate - 6A10.20 An alu-minum plate has been sandblasted on one half.Compare the shiny surface to the diffuse surface.The current model is a square plate of Al.

Angled Mirrors - 6A10.40 The mirrors arehinged at their intersection. Light the candle.Vary the mirror angles to produce a different num-ber of images.

Infinity Mirror - 6A10.45 This demonstrationconsist of a 100% reflecting mirror and a 50%reflecting mirror with a row of Christmas lightssandwiched between them. The viewer can seemany reflections from the lights giving the illusionthat a hole in the wall has been created.

90 OPTICS

Full View Mirror - 6A10.50 How much of themirror is needed to view your entire body. Markwith tape and then measure with two meter stick.

Flying Human - 6A10.80 This demonstrationgives the optical illusion of a person flying. Thedemonstrator stands with his or her legs strad-dling a mirror. He or she then lifts the front legwhich is reflected in the mirror, giving the illusionof flying. Keeping the knees together enhances theillusion.

6A20 Reflection from Curved Surfaces

Blackboard Optics - Curved - 6A20.10 Showreflections off of concave and convex mirrors

Inverted Light Bulb - 6A20.30 With properalignment, the bulb will appear in the emptysockot on top of the box.Turn the demo cart fromside to side so all can see the light bulb.

Disappearing Candy - 6A20.35 Two concavemirrors face each other. An image of a small ob-ject appears to be resting on a convex surface. Tryto touch it.


Virtual Reality Mirror - 6A20.37 The virtualreality mirror is 23cm in diameter and has an idealfocal point of 5.75cm. Suspend a red ball in frontof the mirror and observe both the object and thereal image.

Projected Arrow with Mirror - 6A20.40 Shinethe projector with the arrow shaped filter on itat the concave mirror. An image of the invertedarrow appears on the wall behind the projector.

Convex and Concave Mirrors - 6A20.45 Large16” convex and concave mirrors are shown.

6A40 Refractive Index

Cheshire Cat - 6A40.30 Show how a glass catseems to disappear when immersed in a liquid ofthe same index of refraction of the glass. Thedemo room uses Wesson vegetable oil because ofits close index to Pyrex.NOTE: This demo uses pyrex glass items until the“cat” can be mended (as he’s a bit broken now...)

Mirage with laser - 6A40.47 A laser beam passes over a sheet of aluminum that has been heatedwith a bunsen burner. When the heat is on, the laser image can be seen ’jumping’ around. Afteryou turn the heat off, the image still moves around, but move the plate with a pair of plyers andthe beam movement ceases. Return the plate and the movement also returns.

6A42 Refraction at Flat Surfaces

Blackboard Optics - Refraction - 6A42.10Show refraction through different shaped blocks

92 OPTICS

Nakamura Refraction Tank - 6A42.21 Thelight source can be rotated through 270 degreesto show refraction and total internal reflection forboth water/air interfaces.

6A44 Total Internal Reflection

Blackboard Optics - Total Internal Reflec-tion - 6A44.10 Use a large block or semicircle withthe blackboard optics set to show how light can betrapped.

Laser and Fiber Optics - 6A44.40 You are pro-vided with a Plexiglas curly Q and a section of afiber optics cable. Hold their ends in the beamnear the laser and show how the light travels.

Fiber Optic Christmas Tree - 6A44.401 Differ-ent colors of light travel in loose fiber optic cables.The colors show up on the end of the cables caus-ing the apparatus to look like a Christmas tree.


Television Stone - 6A44.402 The locality ofBoron, California, produces a most unusual formof Ulexite. Gigantic hunks of this mineral arefound in great amounts in the form of fibrous,compact veins. When polished, these specimensbecome the famous “Television Stone” sold to am-ateur collectors. The optical effect exhibited byTelevision Stone is caused by each of its individ-ual fibers acting as fiber-optic cables, transmittinglight from one surface to the other. Since all thefibers are parallel and compacted together, anyimage at one surface is transmitted through eachfiber to the other surface. Thus, any text or imageat the bottom of a specimen appears as if it is ontop. For this effect to be seen, the specimen mustbe polished, since its surfaces must be smooth.

Fiber Optic Wand - 6A44.403 similar to the fiber optic christmas tree, the wand consists of alight source with a group of fiber optic strands attached to the top. Is smaller than the tree.

Dissected Fiber Optic Cable - 6A44.404 The shielding on an industrial fiber optic cable are cutaway to display the interior workings.

Laser and Cylinder - 6A44.44 A laser beam en-ters a special Lucite cylinder at the correct angleand spirals through the cylinder . NOTE: Avoiddirect eye exposure! THIS DEMONSTRATIONNEEDS A DARK ROOM TO BE VIEWED BYA LARGE CLASS.

Water Stream and Light Pipe - 6A44.45 Alaser beam is directed at a stream of water to showtotal internal reflection.

Diamond - 6A44.60 A large glass “diamond” isprovided to demonstrate the principles of total in-ternal reflection.Actual diamonds are cut so that all of the lightentering the top is reflected internally so that itcomes back out of the top, which is why diamonds“sparkle”. While the index of the glass is not largeenough to reflect all of the light, it does reflect agood bit. One way to demonstrate this is to holdthe “diamond” in your hand and notice that it isdifficult to see your hand through the “diamond”.You might also want to order a laser pointer toshow how light moves through the “diamond”.

94 OPTICS

6A46 Rainbow

Dowel Raindrop Model - 6A46.26 Three dowelsare stuck into a Styrofoam ball. The Ball repre-sents a raindrop, the big dowel a beam of lightfrom the sun and two smaller dowels representingblue and red light. Use to show how a rainbow isformed with red on top even though blue light isrefracted above the red when exiting the rainbow.Also use to show why the rainbow is an arc.

Moon Ring - 6A46.261 The ring around theMoon is caused by the refraction of light from themoon as it passes through ice crystals in the up-per atmosphere. The ice crystals are hexagonalshaped, which redirecteds the light into a ring. AMoon ring is almost always the same size.

6A60 Thin Lens

Blackboard Optics - Thin Lens - 6A60.10Show light paths through thin lenses

Projected Filament with Lens - 6A60.30 Turnon the light slide projector. Move the image sourceto focus the image on the side wall.


Projected Arrow with Lens - 6A60.31 Turn onthe lighted arrow object. Move the lens to focusthe image on the wall.

Lens Magnification - 6A60.35 Two different fo-cal length magnifiers can be shown and discussed.

6A65 Thick Lens

Fresnel Lens - 6A65.70 Large converging and di-verging Fresnel lens can be shown and discussed

Fresnel Lens on Overhead - 6A65.701 An oldoverhead projector is supplied without the arm.Turn on the projector and shake chalk dust overthe Fresnel lens. The dust will show a cone of lightcoming into focus. This is a great demo!

96 OPTICS

6B PHOTOMETRY

6B40 Blackbodies

Variac and Light Bulb - 6B40.10 A large lightbulb is plugged into a variac. Slowly turn up thevariac and observe the changing color of the fila-ment. Student diffraction gratings are available.

Hole in a Black Box - 6B40.20 A box is paintedblack on the outside and white on the inside witha hole in the side. The hole appears to be blackuntil the top of the box is removed.

6C DIFFRACTION

6C10 Diffraction Through One Slit

Single Slit and Laser - 6C10.10 Turn on thelaser. The pattern appears on the wall. The slitwidths are printed on the slide. To select a differ-ent slit, slide the holder sideways.

Adjustable Slit and Laser - 6C10.15 Shine alaser beam through an adjustable slit. The centraldiffraction pattern widens as the slit is closed.

6D INTERFERENCE 97

Compound Eye Resolution - 6C10.151 The op-timal size of the facet of a compound eye is deter-mined by a tradeoff between the competing effectsof angular resolution between neighboring facetsand the limits to resolution imposed by diffractionof a single facet. This tradeoff is demonstrated bybringing two nearly co-linear laser beams througha single slit. For two beams of fixed angular sep-aration Q incident on the same slit, the ability toresolve the two beams decreases as the slit size de-creases. For decreasingly small slit size d, two sin-gle slit diffraction patterns overlap so as to makeresolution of the two sources impossible. Similarly,for a fixed slit size d, as the angular separation Qincreases, the two sources become clearly resolved.The demo projects beams of two lasers through aslit with an ability to control the slit size d andthe angular separation of the two sources Q.

6C20 Diffraction Around Objects

Thin Hair Diffraction - 6C20.20 Hold a strandof hair (or we have a thin wire) in the laser beamand observe the diffraction.

6D INTERFERENCE

6D10 Interference From Two Sources

Double Slits and Laser - 6D10.10 Turn on thelaser. The pattern appears on the wall. The slitwidths and spacings are printed on the slide. Toselect different slits, slide the holder sideways.

6D20 Gratings

Gratings and Laser - 6D20.15 Show the diffrac-tion pattern by shining a laser through a diffrac-tion grating.

98 OPTICS

Projected Spectra with Grating - 6D20.20Place paper slit on overhead projector. Then coverthe lens with the Project Star diffraction grating.

Compact Disc Grating - 6D20.32 Use a com-pact disc as a grating. Reflect a laser off the sur-face. The pit and grove’s give a nice pattern.

Babinet’s Slit - 6D20.47 A slit and a line areused to show the spectrum and its complement.

Two Dimensional Grating - 6D20.55 Hold thescreen in the laser beam and observe the two di-mensional pattern.

6D30 Thin Films

Soap Film Interference - 6D30.20 Dip the cylin-der into the soap solution. Adjust the angle untilthe pattern appears on the side wall. Bubble Solu-tion Formula:1/2 Liter Joy dishwashing liquid 1/2Liter warm water 15 Milliliters (one tablespoon)of Glycerine

Soap Film Interference - Monochromatic- 6D30.201 The standard soap film interferencedemo uses a slide projector as the light source. Byinserting a red filter slide into the projector, theinterference patterns are shown as red and blacklines. This demo is not as bright as the regularsoap film demo, but easier for the student to un-derstand.

Thin Film Interference - 6D30.202 Squeeze glass to see thin film interference.

6F COLOR 99

6F COLOR

6F10 Synthesis and Analysis of Color

Color Addition - 6F10.11 The following is thevendors description of the demonstration. Thelight output from the QED Color Mixer is pro-duced by four separate ultra-bright RGB LEDs.Three slide potentiometers control each LED, al-lowing the red (R), green (G), and blue (B) lightfrom each LED to be individually controlled andmixed as desired. Using these revolutionary RGBcontrols, the laws of additive color mixing can bedemonstrated with unparalleled clarity and im-pact. In addition, a set of filters can be placedover the LEDs to demonstrate subtractive colormixing. Six filters that pass either red, green, blue,cyan, magenta, or yellow can be placed over theLEDs ( set to emit white light) to demonstrate theprinciples of subtractive color mixing using filters.It is a simple matter to show the necessity of usingsecondary colors (cyan, magenta, and yellow) forsubtractive mixing, like that used in inkjet print-ing. The QED Color Mixer also has a unique fea-ture found on no other color mixer. The specialarrangement of the four RGB LEDs in the QEDColor Mixer allow light to be passed through fil-ters and mixed either additively or subtractively -at the flick of a switch! Change back and forth be-tween the two modes, showing first the results ofpassing white light through each filter separately,and then mixing them additively on the screen.Then flip a switch to show the results of white lightpassing through all filters in turn, and the effectof subtractive mixing on the resulting colors. Seethe two pictures to the right for an example doneusing cyan, magenta, and yellow filters.

Color Disk - 6F10.25 This disk can be used todemonstrate the effect of a particular combinationof the colors in the spectrum. A succession of colorimpulses, reaching the eye in varying proportionsfrom the rapidly rotating disk, can produce thesensation of white or gray.

Colors in Spectral Light - 6F10.75 View a white and red rose in white, red, green and blue light.

100 OPTICS

6F30 Dispersion

Water Prism - 6F30.10 light passes through theprism and produces a spectrum on the screen.

6F40 Scattering

Sunset - 6F40.10 A beam of light shines through a tank of water and sodium thiosulfate and ontothe side wall. Add a small amount of acid to the water and stir with the stick. The “sun” will beginto turn orange. The scattering will increase until even the reds no longer pass through the tank.

6H POLARIZATION

6H10 Dichroic Polarization

Polaroids on the Overhead - 6H10.10 You gettwo sheets of Polaroid and a pair of Polaroid sun-glasses. Rotate one of the Polaroids or the sun-glasses.

Miscellaneous Polarizers - 6H10.111 Show anassortment of miscellaneous polarized items, suchas sun glasses, lenses and cut up poloarized sheets.

Polarization - Mechanical Model - 6H10.30Dowels are used to construct two polaroids by at-taching them parallel to each other. A string isdriven using a drill to produce circular standingwaves. Use one dowel-polarizer to make the wavepolarized. Use the second dowel-polarizer to showthat when the polarizers are crossed, the wave cannot continue.

6H POLARIZATION 101

6H20 Polarization by Reflection

Brewster’s Angle - 6H20.10 Light is reflectedfrom a sheet of glass onto the wall. Rotate a sheetof Polaroid in the path of the reflected light. Weset the light at Brewster’s angle. Vary the incidentangle by rotating the light. A metal triangle canbe used to set the incident light back to Brewster’sangle. (Glass shown is a microscope slide.)

6H30 Circular Polarization

Three Polaroids - 6H30.10 You get three sheetsof Polaroid of different sizes. Cross two sheets andinsert the third sheet between the first two.

6H35 Birefringence

Birefringent Crystals - 6H35.10 These calcitecrystals are a birefringent medium, so they splitone light beam into two beams. There are differ-ent indices of refraction for different polarizations.In p polarization, n=1.4864 and in s polarizationn=1.6584. Placed on text, images appears double.

Stress Plastic - 6H35.50 Show the stress lines inplastic using polarized light.

102 MODERN PHYSICS

Cellophane Between Polarizers - 6H35.55Place various cellophane, plastic and tape betweenpolarizers.

LCD Element Between Polaroids - 6H35.65 A LCD screen is encased by two polaroids. Whenno power is supplied, the screen appears opaque, but when plugged in to a variac and the current isincreased, the screen turns transparent.

6J THE EYE

6J11 Physiology

Einstein Face Illusion - 6J11.52

6Q MODERN OPTICS

6Q10 Holography

Holograms - 6Q10.10 Several white light holo-grams are available for showing

Modern Physics

7A QUANTUM EFFECTS

7A10 Photoelectric Effect

Discharging Zinc Plate - 7A10.10 A polishedzinc plate sits atop an electroscope. A negativecharge is placed on the electroscope. The UV lightis then shown on the plate to discharge the elec-troscope.

Photoelectric Charging - 7A10.12 Illuminatethe zinc plate on an uncharged electroscope withUV light. Bring the positively charged rod nearthe zinc plate. The electroscope will charge posi-tively.

7B ATOMIC PHYSICS 103

7A50 Wave Mechanics

Vibrating Circular Wire - 7A50.40 The Pasco’ssignal generator drives the Pasco’s mechanical vi-brator. The three node resonance is at 20 Hz.Turn up the amplitude after finding the resonance.Other resonance’s are at 60, 100, 140 Hz.

7B ATOMIC PHYSICS

7B10 Spectra

Student Gratings and Line Sources - 7B10.10Pass out the 1” x 1” gratings to the students.These have 13,400 lines per inch. Turn one of thelight sources. There is a single filament white lightsource and five discharge tubes: H, Ar, He, Hg,and Ne. -CAUTION: Turn off the power supplybefore changing to the next discharge tube.

Spectrum Chart - 7B10.101 Large poster shows continuous spectrum, bright line spectrum forLithium, Sodium, Potassium, Calcium, Strontium, Barium, Zinc, Cadmium, Mercury, Hydrogen,Helium, Neon, Argon and Carbon. Absorption Spectra for Solar, Chlorophyll a, Lycopin, Cy-tochrome, Didymium glass

LED Tower - 7B10.102 This apartus includes 11LED. One is white and the others are differentmonchromatic sources spanning the visible spec-trum. Have students view this with diffractiongratings to see where each color is positioned onthe visible spectrum.

104 MODERN PHYSICS

7B11 Absorption

Glo-Doodler Spectral Absorption - 7B11.40Turn on the slide projector with the slit insidethe slide compartment. Hold the Glo-Doodler be-tween the slide projector and the PASCO diffrac-tion grating. All of the spectrum will show withthe exception of the yellow/yellow green wave-lengths. ( The Glo-Doodler is a kids toy. It isthe pink plastic kids write on with a plastic pen.It is erased when they lift it up.)

7B13 Resonsance Radiation

Fluorescence - 7B13.50 Several colors of SillyPutty are supplied along with a Black Light. Showhow these samples glow brightly in a room illumi-nated by the black light only. Also observer otherthings in the room such as blond hair, teeth, whitet-shirts, shoe strings and socks.

UV Detecting Beads - 7B13.501 UV-sensitivebeads contain a pigment which changes color whenexposed to ultraviolet light from the Sun or otherUV source. The pony beads are not, however, af-fected by visible light and so will remain whiteindoors, or when shielded from UV light.

Luminescence - 7B13.55 A glow-in-the-darkDuncan Imperial Yo-Yo is supplied with a blacklight. Show that the Yo-Yo glows brightly in adark room after being exposed to the black light.(note: the Yo-Yo will also glow after being exposedto room lights).

7D NUCLEAR PHYSICS 105

7B35 Electron Properties

Plasma Globe - 7B35.75 The plasma globe con-sists of a partially evacuated glass sphere contain-ing a mixture of gases at fairly low pressure. Thesmaller sphere at the center of the glass sphere isconnected to a high voltage, high frequency, yetlow current source of alternating current. Touch-ing the glass side will cause a plasma stream toflow to your finger tips. Bring a flourescent tubeclose by and the high voltage will light it.

7D NUCLEAR PHYSICS

7D10 Radioactivity

Geiger Counter and Samples - 7D10.10 Listento a Geiger counter when radioactive samples aretested. The samples are from a Radioactive Min-eral Collection. The samples are as follows: Al-lanite Ontario, Canada Autunite New Hampshire,USA Carnotite Utah, USA Ellsworthite Ontario,Canada Samarskite North Carolina, USA Uran-othorite Ontario, Canda

7F RELATIVITY

7F10 Special Relativity

Lorentz Transformation - 7F10.60 The Mechanical Universe video disc, Program 42, discusseslength contraction, time dilation, and space-time. Preview chapters 25,26, and 39-43. The film,“Relativistic Time Dilation”, is a Paul Hewitt cartoon focusing on the twin paradox.

Astronomy

8A PLANETARY ASTRONOMY

8A10 Solar system Mechanics

Trippensee Planetarium - 8A10.10 A model ofthe Earth, Moon, Venus and their motion aroundthe sun. Can be used to discuss seasons, tides andeclipses.

106 ASTRONOMY

Local Zenith - 8A10.20 Move the arrow to dif-ferent latitudes The sun is optional

Pinhead Earth - 8A10.40 A common pin and 30 gauge (.010”) wire are mounted in a smallStyrofoam block about 1 1/4” apart. The sun/earth/moon system is scaled when a softball is held40’ away. Pass the earth/moon around the class.

Solar System on a String - 8A10.451 Thisstring illustrates a scaled down version of our so-lar system; it has markings of where each planet inour solar system lies with respect to one another.The string-solar system is 35.84 meters long.

Celestial Sphere - 8A10.80 Plastic Model of thesky.

8A20 Planetary Geology

Globes - 8A20.10 Model of Earth

Seasonal Globe - 8A20.101 The seasonal globe isilluminated from the interior. A dial on the globeallows you to select a season. The students caneasily see why the sun does not set on the northpole in June. Why Brazil is warmer in December.If you dim the lights, you can also use this globeto demonstrate phases of the moon.

8B STELLAR ASTRONOMY 107

8B STELLAR ASTRONOMY

8B10 Misc.

Forward and Backward Scattering - 8B10.40 Make a chalk cloud with erasers both behind andin front of a light bulb.

Pulsar Model - 8B10.65 Tape a flashlight and abar magnet on a turntable. Alternately, tape theflashlight and magnet on a helmet and sit on therotating stool.

8C COSMOLOGY

8C10 Models of the Universe

Expanding Universe - 8C10.10 Five Styrofoamballs are threaded onto a rubber cord at equal in-tervals. Pull on the free end an watch the expand-ing intervals. The top illustration shows the ballsstretched out and the bottom shows the balls un-stretched.

Inflating Balloon - 8C10.15 A balloon is at-tached to an air supply. To inflate the balloon,turn on the air. Make marks on the balloon withthe marker provided.

Bubble Universe - 8C10.20 Use the straw toblow bubbles in the soap solution. Blow veryslowly to make big bubbles. Use a TV camerato look at the bubbles.

108 EQUIPMENT

Equipment

9A BLACKBOARD TOOLS

9A10 Blackboard ToolsBlackboard Compass - 9A10.10 A large wooden compass for drawing arcs and circles on theblackboard.

Protractor - 9A10.12 A large wooden protractor for use on the blackboard.

Movable Whiteboard - 9A10.401 Small whiteboard that can be moved from room to room.

9A20 AudioWireless Microphone - 9A20.10 These are built into Dabney 222, 124, Cox 206 and Cox 214. Askfor microphone

CD Player - 9A20.20 Sony CDP-CE215 5 Disc changer

Audio Cassette Player - 9A20.30 Sony Dual Cassette Player model number TC-WE305

9A30 Slide Projectors

Portable Screen - 9A30.05 This screen has a silvered surface for optics demonstrations. It canalso be used for presentations.

35 mm Slide Projector - 9A30.10 Long extension for remote is available

Laser Pointer - 9A30.30 Small helium-neon laser pointer.

9A34 Film Projectors

16 mm Film Projector - 9A34.10 It rattles and rumbles, but it still works. We have a nicecollection of old films.

Film Loop Projector - 9A34.20 For showing the Ealing film loops.

9A36 Overhead Projectors

Overhead Projector - 9A36.10 These are now supplied by the university and are in each classroom.We have several here in the demoroom for checkout.

Projection Galvanometer - 9A36.20 Used mainly for demonstrating Faraday’s Law.

9A38 Video & Computer Projection

Video Projectors - 9A38.20 We currently have 1 projector. It accepts VGA, composite andS-Video inputs.

Monitor on Cart - 9A38.261 25” Television on rolling cart.

Laserdisc Player - 9A38.30 This is usually supplied with any television on a cart.

VCR - (VHS Format) - 9A38.40 Supplied with each television on a cart.

3/4 Inch Tape Deck - 9A38.45 This thing is old and has a history of eating tapes. If you havea 3/4 tape you would like to view, let us know ahead of time. We can clean the player and dub acopy to VHS for you.

PC - Laptop (Dell or Gateway) - 9A38.50 This laptop computer will be the Gateway if yourclass is in 206/204 or the Dell if your are in 214/200.

9B ELECTRONIC 109

9A40 Photography

VideoFlex Camera - 9A40.25 This is a gooseneck camera. It can focus from 1mm to infinity.Excellent for showing small demonstrations with a projection system or television.

9A73 Unclassified Demonstrations

Unclassified Demonstration - 9A73.00 Anything that does not have a number can be listed underthis demonstration. If a particular demonstration is requested enough, it will be added to the lineup. This number is mainly for demos involving a shoe string, piece of tape, racquet balls and papertowels.

Classroom Clicker File - 9A73.10

9B ELECTRONIC

9B10 Timers

Analog Timer - 9B10.70 Set the time on the dialsand turn it on. The volume level of the buzzer isvariable. Timer can be set from 1 second to 60minutes.

9B60 Light Sources

Sodium Vapor Lamp - 9B60.60 The sodium va-por lamp generates an intense (6 candela/cm2)source of monochromatic radiation. 99.5% of thevisible output is in the 5889 and 5895 angstromspectral lines. Use it for showing demonstrationsof color perception, interference, diffraction, andspectroscopy.

9C MECHANICAL

9C10 Motors

Bicycle Wheel Motor - 9C10.00 Order this motor if you want to spin up a bicycle wheel veryquickly, especially for the bicycle wheel gyro.

9C20 Pumps

Air Compressor - 9C20.10 Can also be ordered with the air tank.

110 EQUIPMENT

Fog Machine - 9C20.26 Plug in the fog machine. It will take several minutes to warm up. Thenpress the button when you want fog to emitted.

Can Smoke - 9C20.261

9C40 OtherBathroom Scales - 9C40.901 A set of bathroom scales measuring US pounds.

9C MECHANICAL 111

16 mm Film Projector 1042 X 4 Attraction 653 to 1 Collision Balls 233/4 Inch Tape Deck 10435 mm Slide Projector 1044 to 1 pendulum 39Acceleration Block 11Acceleration Pendulum Cart 12Adjustable Slit and Laser 92Air Compressor 105Air Track and Glider 3Ames Tube 49Analog Timer 105Angle of Repose 19Angled Mirrors 86Arago’s disk 81Archimede’s Principle 34Area Dependence of Friction 18Astro-Blaster 24Atmosphere Bar Lead Bar 33Attracting Sheets 37Atwood’s Machine 11Audio Cassette Player 103Auditory Demonstrations 49Babinet’s Slit 93Back EMF 79Baffle and Speaker 48Baffles and Resonators 48Balancing Bear 16Balancing Bird 16Balancing a Bat 24Ball and Funnel 37Ball and Ring 54Ball in Track 21Ball on a String 6Ball to Throw 7Ball-Block Collision 23Ball-Spring Model 31Ballistic Pendulum 21Balloon Bed of Nails 19Balloon Rocket 22Balloon in Liquid Nitrogen 61Balloon in a Vacuum 61Basic Unit Set - VEPD 01-01 1Bathroom Scales 105Beat Bars 49Beat Forks 48Beat Speakers 49Bed of Nails 19Beer Can Pith Balls 64Bell in a Vacuum 46Bending Beam 30Bicycle Wheel Gyro 28Bicycle Wheel Motor 105Bimetal Strip 54Birefringent Crystals 97Blackboard Compass 103Blackboard Optics - Curved 86Blackboard Optics - Plane Mirror 85Blackboard Optics - Refraction 88Blackboard Optics - Thin Lens 90Blackboard Optics - Total Internal Reflection 88Blinky Whirligig 84Boiling by Cooling 59Boomerang 37Booms 17Bounce/No Bounce Balls 31

Bowling Ball Pendulum 21Brewster’s Angle 97Bubble Universe 103Buoyancy, Aquarium, and Nails 35Burst a Balloon 59CD Player 103Can Smoke 105Capacitor with Dielectrics 69Capillary Tubes 32Carbon Dioxide 60Cartesian Diver 35Catch a Dollar 4Catch a Meter Stick 4Catch the Ball 26Cathode Ray Tube 78Celestial Sphere 102Cellophane Between Polarizers 98Center of Gravity of a Broom 14Center of Mass of Non-rigid Object 6Chaotic Pendulum 43Charge From a 10 kV Power Supply 71Charge Propelled Soda Can 65Charge and Discharge a Capacitor 70Cheshire Cat 87Chinese Water Spouting Basin 47Chladni Plates 52Classroom Clicker File 104Coefficient of Restitution 31Cohesion Plates 32Coil in Liquid Nitrogen 70Collision Balls 23Color Addition 95Color Disk 95Colors in Spectral Light 95Combustion Cannon 66Compact Disc Grating 93Compass 75Compound Eye Resolution 92Compressing a Spring 30Conic Sections 20Constant Volume Bulb 62Convection of Liquids 56Convex and Concave Mirrors 87Coupled Pendula 42Coupled motor/generators 83Coupled speaker/tuning fork 49Critical Opalescence 60Crookes Radiometer 60Crookes Tube 78Crossing the River 8Crush the Soda Can 33Curie Temperature 73Current in Lamp Circuit 71Curve Ball 37Damped Harmonic Oscillator 41Damped Harmonic Oscillator with Position Plot 41Density Ball 35Diamond 89Different Mass Pendula 39Different Radii Discs 17Diffuse Aluminum Plate 85Digital Sound Level Meter 50Digital Thermometer 53Dip Needle 75Disappearing Candy 87Discharge a Capacitor 70Discharging Zinc Plate 98

112 EQUIPMENT

Dissected Fiber Optic Cable 89Dissectible Condenser 69Doppler Ball 47Doppler Reed 47Doppler Spear 47Double Ball Bounce 24Double Cone 15Double Pendulum 42Double Slits and Laser 93Double Wheel Gyro 28Dowel Raindrop Model 90Drinking Bird 59Driven Mass on a Spring 41Drop Bags of Rice 26Drop Ball and Paper 4Drop Lead and Cork Balls 3Drop the Cat 27Dropped Slinky 12Dropping Lead Shot 57EM Field Software 67EM Desktop Experiment Kit 72Eddy Current Brake 80Eddy Current Levitator 81Eddy Current Pendulum 80Egg in Sheet 22Eggs and Pizza Pan 10Einstein Face Illusion 98Electric Field Lines 67Electric Wind 69Electrified Strings 67Electrodeless Discharge 84Electromagnet 73Electronic Keyboard 50Electrophorus 63Electroscope Charging By Induction 64Electrostatic Ping Pong 67Ellipsoid 29Equal Time Equal Distance Drop 4Equal Torques, But Not Equal Masses 14Eternity Flashlight 83Euler Angles 2Expanding Universe 103Expansion Cloud Chamber 58Exploding Racquetball Can 59Falling Meter Sticks 25Falling off the Merry Go Round 7Faraday Repulsion Coil 80Faraday’s Ice Pail 68Faraday’s Ice Pail (large) 68Faster Than ’g’ 25Fiber Optic Christmas Tree 89Fiber Optic Wand 89Field of Wire and Iron Filings 76Film Loop Projector 104Fire Syringe 58Flattening Earth 7Float Accelerometer 12Floating Ball 36Floating Ball (hair dryer) 37Floating Ball (leaf blower) 36Floating Bowling Balls 35Floating Coke Cans 35

Floor Cart and Medicine Ball 13Fluorescence 100Flying Human 86Fog Machine 105Force Between Parallel Wires 78Fork, Spoon and Match 15Forward and Backward Scattering 102Fourier Synthesizer 50Fourteen Nails on One 15Frames of Reference 8Freezing Liquid Nitrogen 59Fresnel Lens 91Fresnel Lens on Overhead 91Friction Blocks 18Front and Rear Brakes 19Full View Mirror 86FunFlyStick 66Gas Law Apparatus 58Gee-Haw Whimmydiddle 40Geiger Counter and Samples 101Glass and Card Trick 34Glo-Doodler Spectral Absorption 100Globes 102Governor 27Gratings and Laser 93Grip Bar 17Gyro with Adjustable Weights 28Hair on End 66Hand Crank Generator 83Hand Crank Wave Machine 44Hand Cranked Longitudinal Wave Generator 45Hand in LN2 - Leidenfrost Effect 57Hank Cranked Motor/Generator 83Heat from Colliding Steel Spheres 57Hero’s Engine 28High Road/Low Road 5Hit the Nail on the Head 9Hole in a Black Box 91Holograms 98Homemade DC Motor 82Homemade Electromagnet 73Homemade Homopolar Motor 82Hoot Tubes 51Howitzer 7Howitzer on an Incline 7Ignition Bottle 69Impedance Matching - Shive Model 46Impulse Pendulum 23Inch Cubes 1Inclined Airtrack/Pasco Carts 4Induction Coil with Magnet 79Induction Coil with Power Supply 79Induction Coils with Radio 80Inductor Assortment 79Inertia Balance 9Inertia Ball 9Inertia Wands and Two Students 24Infinity Mirror 86Inflating Balloon 103Inverted Light Bulb 87Iron Filings Domain 72Iron Filings in Oil 75Irritating Collision Balls 23Jacob’s Ladder 71Jensen Steam Engine 63Jumping Ring 80Jumping Wire 78

9C MECHANICAL 113

Kinetic Energy of a Rolling Disk 25Kirchhoff’s Voltage Law 71Kneeling Human 14Kroogah Tubes 51LCD Element Between Polaroids 98LED Tower 99Laser Pointer 104Laser and Cylinder 89Laser and Fiber Optics 88Laser and Flat Mirror 85Laserdisc Player 104Lead Bell - Retired 55Leaning Tower of Pisa 14Lens Magnification 91Levers 21Levitating Foil 78Levitation Magnets 77Levitron 77Leyden Jar with Wimshurst machine 69Lifting a Weight with a Capacitor 70Lightning Plate 68Liquid Nitrogen Canon 59Liquid Nitrogen Hovercraft 59Lissajous Sand Pendulum 42Local Zenith 101Lodestone 72Longitudinal Standing Waves 45Longitudinal Wave Demonstrator 44Longitudinal Wave Spring 45Loop the Loop 21Loose Hammer Head 10Lorentz Transformation 101Luminescence 100Magdeburg Hemispheres 33Magdeburg Plates 33Magnet Assortment 72Magnet and Iron Filings 75Magnetic Field from a Coil 77Magnetic Induction 72Magnetic Paper Clip Arrow 74Magneto-Rheological (MR) Fluid 74Magnets and Pivot 77Magnets and Tubes 80Map of North Carolina 13Marshmallow Man 61Mass on a Scale 11Mass on a Spring 40Meissner Effect 73Melde’s Vibrating (elastic) String 45Melde’s Vibrating String (variable tension) 45Melting Wax 56Memory Wire 63Mercury Thermometer 53Metal Resonance Strips 41Metal Rod Attraction 65Meter Stick Vectors 2Meterstick on Fingers 14Microphone and Oscilloscope 50Mirage with laser 88Miscellaneous Polarizers 96Mitac Gyro 28Moire Pattern and Transparencies 48Mole Samples 1Molecular Model Kit 31Molecular Motion Demonstrator 60

Monitor on Cart 104Monkey and Hunter 8Moon Ring 90Motion Up an Inclined Plane 11Motor and Generator Demonstration Model 82Movable Whiteboard 103Move Wire in Horseshoe Magnet 79Multiple Coils with Magnet 79Musical Goblet 52Nakamura Refraction Tank 88Newton’s Sailboard 13Oersted’s Effect - Apparatus 75Oersted’s Effect - Simple Wire with Compass 75Orbits in a Spherical Cavity 19Organ Pipes 51Overhead Projector 104PC - Laptop (Dell or Gateway) 104Pail of Water/Pail of Nails 6Painted Meter Stick 1Palm Glass 60Parabolic Trajectory 8Parallel Plate Capacitor 69Paramagnetism of Liquid Oxygen 73Pascal’s Vases 32Pasco Dynamics Cart 3Passing the Wheel 26Pen and Embroidery Hoop 10Penny and Feather 3Penny on the Coat Hanger 6Phase Interference of Speakers 48Photoelectric Charging 98Physical Pendulum 40Piezoelectric Popper 71Pile Driver 20Pile Driver with Pop Cans 20Pinhead Earth 101Pinwheel 69Pith Balls 64Plasma Globe 100Plumbers Friend 33Polarization - Mechanical Model 96Polaroids on the Overhead 96Poly Density Bottle 36Portable Screen 104Potential-Kinetic Energy Tracks 5Powers of Ten 2Pressure Globe 34Project a Tuning Fork 53Projected Arrow with Lens 90Projected Arrow with Mirror 87Projected Filament with Lens 90Projected Spectra with Grating 93Projected Spectrum with Prism 85Projection Galvanometer 104Protractor 103Pulley System 20Pulling on the Whirligig 27Pulsar Model 103Pump a Swing 43Push Me Pull Me Carts 13RLC 83Racing Disks 25Racing Soups 25Radiation and Polarization - Decimeter Wave Trans-mitter 84Raketti Block 37Range of Hearing 50

114 EQUIPMENT

Range of a Gun 8Rattleback 22Reaction of Secondary on Primary 81Reflection - Shive Model 46Resistance Model 70Resistor Assortment 70Reverse Leidenfrost Effect 57Right-Hand-Rule Prop 76Ripple Tank - Double Slit 48Ripple Tank - Single Slit 47Ripple Tank - Two Point 47Ripple Tank Film Loops 48Rods and Fur with Electroscope 63Rods and Pivot 64Rolling Uphill 18Rope and Three Students 16Rotating Hoberman Sphere 27Rotating Stool and Bicycle Wheel 27Rotating Stool with Dumbbells 26Rubber Rope 43Ruben’s Tube 51Sagging Wire 54Sail Against the Wind 17Sample Capacitors 69Sample Transformers 81Seasonal Globe 102Series and Parallel Capacitors 70Series and Parallel Light Bulbs - 5 Bulb Small 72Series and Parallel Light Bulbs - 5 bulbs Large 71Series and Parallel Light Bulbs - Two Bulbs 72Shattering Goblet/Beaker 52Shaving Cream in a Vacuum 61Shear Book 30Simple Pendulum 38Simultaneous Fall - Large 7Simultaneous Fall - Small 7Singing Rods 52Single Slit and Laser 92Slinky on Table 44Small Transformer 81Smash Your Hand 9Smashing Flower 55Smashing Racquet Ball 55Smashing Tube 55Soap Film Interference 94Soap Film Interference - Monochromatic 94Soda Bottles and Dollar Bill 10Sodium Vapor Lamp 105Solar System on a String 102Solenoid and Iron Filings 76Sonometer 51Speaker Bar 48Spectrum Chart 99Speed of Sound in a Metal 46Speed of a Slinky 44Spinning Football 29Spoon on Nose 15Spring Coupled Pendula 42St. Louis Motor 82Stability of Orbits 27Standards of Length 1Standards of Mass 1Static vs. Sliding Friction 19Stirling Engine 62Stopped Pendulum 21

Stress Plastic 97Stretching a Spring 30Student Gratings and Line Sources 99Suction Cups 33Suitcase Gyro 29Sunset 96Superconductivity 74Surface Tension Bottle 32Suspended Block 16Suspended Slinky 44Sweet Spot of Baseball Bat 40Sympathetic Resonance 49Table Cloth Pull 10Tacoma Narrows Bridge Collapse 41Television Stone 89Tension in a String 16Terminal Velocity - Coffee Filters 38Terminal Velocity - Styrofoam 38Terminal Velocity of Dropped Balls 37Tesla Coil with Fluorescent Lamp 84Tesla and Light Bulb 85The Pendulum Wave - Large 39The Pendulum Wave - Small 39The Visible Stirling Engine 62The Wave - Longitudinal 44The Wave - Transverse 43Thermoelectric Pair 53Thermostat Model 54Thin Film Interference 94Thin Hair Diffraction 92Three Polaroids 97Throwing Board 5Tippee Top 29Tipping Block 18Tipping Block on Incline 14Toilet Seats 56Tornado Tube 38Torque Beam 17Torque on a Coil 78Torroid and Iron Filings 77Torsional Pendulum 39Tossing the Book 29Tower of Lire 15Toy Helicopter 13Train Whistle 52Transmission Lines 84Transverse Standing Waves 45Transverse Wave Generator 44Trapeze Gyro 29Trippensee Planetarium 101Truck on Moving Sheet 3Tuning Forks 53Two Chaotic Pendula 43Two Dimensional Grating 93UV Detecting Beads 100Ultrasonic Ranger and Student 5Unclassified Demonstration 104Unmixing Demo 62Upright Coupled Oscillator 42VCR - (VHS Format) 104Vacuum Cannon 34Van De Graaff Generator 66Van De Graaff with Streamers 66Van De Graaff with Styrofoam Peanuts 67Van de Graaff with Ball and Point 68Van de Graaff with Jumping Pie Plates 67Variac and Light Bulb 91

9C MECHANICAL 115

Vector Addition (head to tail) vepd 01-03 2Vector Addition (parallelogram) vepd 01-02 2Vector Addition and Subtraction 2Vector Components - VEPD 01-04 2Velocity of Efflux - Three Hole Can Experiment 36Venturi Meter 36Vertical Transformer 81Vibrating Circular Wire 99Video Projectors 104VideoFlex Camera 104Virtual Reality Mirror 87Vortex Cannon 38Vortex Cannon - Large 38Walk the Plank 22Walking the Spool 18Water Balloon Heat Capacity 57Water Glass Parabola 7Water Prism 96Water Rocket 22Water Stream and Light Pipe 89Wave Superposition - Shive Model 46Weigh Submerged Block 34Weight Dependence of Friction 18Which is a Magnet? 72Whirligig 6Wilberforce Pendulum 41Wimshurst Machine 65Wine Bottle Balance 16Wire Coil Thermostat 54Wireless Microphone 103Xylophone 52

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