1. Waves Part II: Behavior

2. The Wave Machine http://www.cbu.edu/~jvarrian/applets/waves2/simwav_g.htm Standing Waves Standing waves are a result of interference. Standing waves are a result of interference. –Combination of incident and reflected waves Two waves of equal amplitude and wavelength pass in opposite directions. Two waves of equal amplitude and wavelength pass in opposite directions. Node – stationary point where waves are always out of phase. Node – stationary point where waves are always out of phase. Antinode – largest point of amplitude Antinode – largest point of amplitude

3. Standing Waves Due to interference Nodes “out of Phase” Antinodes “In phase”

4. Interference - waves combine Destructive or Constructive Interference http://users.erols.com/renau/wave_interference.html

5. Principle of Superposition When two or more waves meet, there is interference. When two or more waves meet, there is interference. The displacement caused by two or more waves is the algebraic sum of the individual waves The displacement caused by two or more waves is the algebraic sum of the individual waves Constructive interference – waves in phase add Constructive interference – waves in phase add Destructive interference – waves out of phase subtract Destructive interference – waves out of phase subtract

6. Reflection When wave reaches a barrier at least part of the wave bounces back. When wave reaches a barrier at least part of the wave bounces back. Angle of incidence equals the angle of reflection Angle of incidence equals the angle of reflection http://www.physicsclassroom.com/mm edia/waves/fix.html http://www.physicsclassroom.com/mm edia/waves/fix.html http://www.physicsclassroom.com/mm edia/waves/fix.html http://www.physicsclassroom.com/mm edia/waves/fix.html

7. Change in Media A place where the substance the wave is traveling through changes A place where the substance the wave is traveling through changes Example: A light wave traveling through air passes through a glass window Example: A light wave traveling through air passes through a glass window Some of wave is transmitted and some is reflected Some of wave is transmitted and some is reflected

8. Refraction When a wave travels in a different medium the velocity changes When a wave travels in a different medium the velocity changes This change in velocity results in bending of the wave. This change in velocity results in bending of the wave. This is why a pencil appears to bend in a glass of water. This is why a pencil appears to bend in a glass of water.

9. Diffraction Waves normally travel in a straight line in a medium. Waves normally travel in a straight line in a medium. When waves meet a barrier, they bend around the edges. When waves meet a barrier, they bend around the edges. This is called diffraction. This is called diffraction. http://www.control.co.kr/java1/mason g/oneslit.html http://www.control.co.kr/java1/mason g/oneslit.html http://www.control.co.kr/java1/mason g/oneslit.html http://www.control.co.kr/java1/mason g/oneslit.html

10. http://library.thinkquest.org/19537/java/Doppler.html http://www.control.co.kr/java1/masong/doppler.html The Doppler Effect The apparent change in frequency of a wave due to the motion of the source or receiver. The apparent change in frequency of a wave due to the motion of the source or receiver. Greater speeds produce greater effects. Greater speeds produce greater effects.

11. Doppler effect - Examples car horn car horn sirens sirens radar gun radar gun light light –increase frequency – blue shift –decrease frequency – red shift