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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.