Waves

Mrs. QuinnSpring 2010

Wave A disturbance that

transfers energy through matter or space

When a wave moves through matter, the particles of matter do NOT move along with the wave.

Only the energy that produces the wave moves with the wave.

http://oraclespeak.files.wordpress.com/2009/12/wave.jpg

Example of Waves

http://mendocoastcurrent.files.wordpress.com/2008/12/wave-ocean-blue-sea-water-white-foam-photo.jpg

http://www.physicalgeography.net/fundamentals/images/epicenter.gif

http://hclibrary.org/teachernotes/wp-content/uploads/image/sound_wave.jpg

http://www.abc.net.au/science/features/quantum/img/wave.jpg

Medium Any substance or

region through which a wave is transmitted

A medium transfer wave energy but has no overall movement itself energy is transmitted, but matter is not.

http://odin.physastro.mnsu.edu/~eskridge/astr101/Surface_waves.jpg

2 Properties of a Medium that Affect the Speed of a Wave

1. Density As density of medium increases,

speed of a wave decreases.2. Elasticity This refers to the ability of a medium

to return quickly to its original shape after being disturbed.

More elastic, the faster the wave.

Example of Mediums

Water Ocean Waves

Air Sound Waves

All phases of Matter can act as a medium.

Light does not need a medium it can be transmitted through a vacuum.

Review Questions 1. How does a wave move through a

medium? 2. What are the 2 properties affect

the speed of a wave? 3. At 25 degrees Celsius, the speed of

sound in the 346 m/s. At zero degrees, the speed of sound in air is 332 m/s. Explain why the speed decrease as the temperature decreases?

Types of Waves

Wave are classified according to the motion of the medium as compared to the movement of the wave.

Types of Waves

1. Transverse A wave in

the which the motion of the medium is at right angles to the direction of the wave.

http://media.tiscali.co.uk/images/feeds/hutchinson/ency/c02631.jpg

Types of Waves

Longitudinal A wave that consists of a series of

compression and rarefactions. The motion of the medium is parallel

to the direction of the wave.

http://www.passmyexams.co.uk/GCSE/physics/images/long_waves.jpg

Motion of the Medium back and fourth.

Compression

http://www.physicsclassroom.com/class/sound/u11l1c.cfm

Compression

A space in the medium in which the molecules are crowded together.

Rarefaction A space in the medium in which there are

fewer molecules.

http://www.lcse.umn.edu/specs/labs/images/rarefaction_spring.gif

Review Questions

1. What are the 2 types of waves? 2. Which type of wave is an ocean

wave? 3. Which type of wave is a sound

wave?

Review Questions

4. Suppose that a long line of people formed outside a movie theater and a person at the end of the line pushes the person in front of him. Everyone in line moves forward and then as people regain their balance then move back again. Which type of wave is generated? Why?

http://gilmore2.chem.northwestern.edu/images2/e_simple1.gif

Characteristics of Waves

Amplitude Wavelength Frequency

Amplitude The maximum

distance the molecules of a medium are displace from their rest potential.

Indicates the energy of the wave.

As energy increases, amplitude increases.

http://schools.utah.gov/curr/science/core/8thgrd/sciber8/forces/html/WAVENRGY.HTM

Wavelength The distance

between 2 consecutive crests or troughs

Measured in meters or centimeters

Frequency The number of

complete waves, or complete cycles per unit of time.

Measured in Hertz (Hz)

http://www.qrg.northwestern.edu/projects/vss/docs/media/Communications/frequency.gif

Website

http://library.thinkquest.org/19537/java/Beats.html

This is a hyperlink, just click on it.