MagnetismMagnetismResources:Grob: Basic Electronics Textbook: Chapter 14http://www.coolmagnetman.com/magindex.htmhttp://www.sayedsaad.com/fundmental/3_Basic%20AC%20Generation.htm

http://micro.magnet.fsu.edu/electromag/java/index.htmlhttp://www.regentsprep.org/Regents/physics/phys03/dinduction/default.htm

http://www.exploratorium.edu/snacks/iconmagnetism.html

http://www.school-for-champions.com/science/magnetism.htmhttp://www.school-for-champions.com/science/magnetism.htm

ObjectivesObjectives Formulate a definition of magnetism.Formulate a definition of magnetism. Identify types of magnets.Identify types of magnets. Define permeability.Define permeability. Describe the principle of Describe the principle of

electromagnetism.electromagnetism. Describe how to determine the polarity of Describe how to determine the polarity of

an electromagnet using the left hand rule.an electromagnet using the left hand rule. Describe some uses of magnetism.Describe some uses of magnetism. Define electromagnetic induction /how to Define electromagnetic induction /how to

increase induced current.increase induced current.

Historical PerspectiveHistorical Perspective 44thth Century Chinese & Ancient Greeks in Century Chinese & Ancient Greeks in

city of Magnesia: Loadstone from lava city of Magnesia: Loadstone from lava flowsflows

1212thth Century Chinese: Compass Century Chinese: Compass

1616thth Century: William Gilbert, Century: William Gilbert, Physician to Queen Elizabeth Physician to Queen Elizabeth suggested that the earth must suggested that the earth must be a magnet. be a magnet.

Modern CompassModern Compass

Earth’ Magnetic FieldEarth’ Magnetic Field MagnetosphereMagnetosphere

Van Allen beltVan Allen belt Aurora BorealisAurora Borealis

Types Of MagnetsTypes Of Magnets PermanentPermanent

Electromagnet (Temporary)Electromagnet (Temporary)

Permanent Magnets: Permanent Magnets: What Causes Magnetism?What Causes Magnetism?

Electron Spin and OrbitElectron Spin and Orbit Dipoles Lining UpDipoles Lining Up

Flux LinesFlux Lines

Demo degaussing CoilDemo degaussing Coil

Magnetism PropertiesMagnetism Properties Like Poles RepelLike Poles Repel Unlike Poles AttractUnlike Poles Attract

DefinitionDefinition

Definition: Magnetism is an invisible Definition: Magnetism is an invisible force field which acts upon some force field which acts upon some materials but not upon others. materials but not upon others.

Magnetism has an effect on all Magnetism has an effect on all materials but some materials have the materials but some materials have the ability to strengthen this effect more ability to strengthen this effect more than others.than others.

Permeability (ability to concentrate flux)Permeability (ability to concentrate flux)

PermeabilityPermeability

0

5000

10000

15000

20000

25000

Al Cu Steel Permalloy Mumetal Alnico Ferrite

Permeability

Electromagnetism: The Catalyst For Electromagnetism: The Catalyst For Technological Invention and Innovation Technological Invention and Innovation

Hans Oersted

Revolutionary War

Abraham2000 BC

Moses 1400 BC

Isaiah800 BC

Jesus andApostles

Constantine300 AD

Gutenberg1400 AD

Watt1765 AD

Volta / Galvani 1800 AD

Dark Ages

Columbus1492 AD

Transportation (mph)

Communication

Information Management

Electromagnets: Hans Electromagnets: Hans OrstedOrsted

Demo of Orsted's ExperimentDemo of Orsted's Experiment

ElectromagnetsElectromagnets

Effect of Oersted’s DiscoveryEffect of Oersted’s Discovery

Hans Oersted

ComputersFax MachinesCell PhonesCD’s / DVD’sInternet

Edison: Light Bulb1879

Ampere: Electrodynamics 1821BC

FaradayElectromagnetism1821 Wright Bros

Air Flight1903

Benz: Automobile1885

1890Electric PowerAvailable

Bell Labs: Transistors1947

Marconi: Radio1896

Bell: Telephone1876

Transportation (mph)

Communication

Information Management

Farnsworth: TV1927Morse: Telegraph

1835

Oersted’s discovery wasIn the Spring of 1820

Ways to strengthen an Ways to strengthen an ElectromagnetElectromagnet

Coil the WireCoil the Wire

Increase the number of Increase the number of coils per given areacoils per given area

Add a permeable coreAdd a permeable core

Increase the current!Increase the current!

Determining the Polarity of an Determining the Polarity of an ElectromagnetElectromagnet

Using your left hand, wrap your Using your left hand, wrap your fingers around the coil the same fingers around the coil the same direction that the electrons will flow. direction that the electrons will flow. Your thumb is pointing to the north Your thumb is pointing to the north pole of the electromagnetpole of the electromagnet

_ +

Left Hand Rule Left Hand Rule (Checking for Understanding)(Checking for Understanding)

Draw on BoardDraw on Board Change polarity of sourceChange polarity of source Change direction of windingChange direction of winding

Common uses of magnetismCommon uses of magnetism MotorsMotors InductorsInductors GeneratorsGenerators TransformersTransformers RelaysRelays SolenoidsSolenoids Speakers/MicrophonesSpeakers/Microphones Information Storage DevicesInformation Storage Devices

Teacher Note: Scattegories Game??Teacher Note: Scattegories Game??

Magnetic RelayMagnetic Relay

Relay OperationRelay Operation

SolenoidSolenoid

Draw Operation on boardDraw Operation on board Solenoid Operation: DoorbellSolenoid Operation: Doorbell

Speaker / MicrophoneSpeaker / Microphone Speaker Operation Speaker Operation (continue through step 6)(continue through step 6)

Speaker Operation #2Speaker Operation #2

Magnetic Storage DevicesMagnetic Storage Devices Hard Drive OperationHard Drive Operation

Electric MotorElectric Motor Electric Motor OperationElectric Motor Operation Beakman’s motor labBeakman’s motor lab

Single Pole Pulse Motor Single Pole Pulse Motor (Beakman’s)(Beakman’s)

1.1. Choose a dowel the size you want to Choose a dowel the size you want to make your motormake your motor

2.2. Using enamel coated wire loop the Using enamel coated wire loop the wire in the following configurationwire in the following configuration