2.  A vibration that repeats regularly in space and time  Transmitted from one place to another w/out actually transporting matter  A transmission of Energy  Require a medium (substance to travel through)  Ex. Water waves, sound, wave in string/spring

4.  Wavelength – (λ) – distance between identical parts of a wave. Length of wave  Amplitude (A)– height of a wave  Period (T) - time for one full wave to pass  Frequency (f) – cycles per second … how many full waves pass by per second

5.  Frequency = 1/ Period  Period = 1 / Frequency  Reciprocals of each other….  Waves per time (frequency)  Time per wave (Period)

6.  Any regularly repeating vibration  Pendulum  Spring  Vibrations caused in buildings by wind  Steps of a person walking  Rules for waves can be used for anything that fits in this category

7.  Transfers energy not matter  If stone dropped in water, the disturbance moves not the water

8.  Wave speed depends on the medium  The more rigid the medium the faster sound will travel through it  Wave speed = frequency X wavelength  v = f λ

9.  Medium vibrates in a directions perpendicular to the direction of the wave

10.  Medium vibrates in the same direction that the wave moves

11.  Constructive Interference  Waves can interfere w/ each other so that they add together to produce a larger wave  Destructive Interference  Waves can interfere w/ each other so that they subtract each other and cancel out  Demos

12. Out of phase – Destructive interference In phase – Constructive interference

14.  When waves collide w/ a barrier they have a tendency to wrap around the barrier  Break walls at the beach  This is why we can hear a person talking even if they are around the corner

16.  Tsunamis are large waves generated by a large earthquake or massive landslide  Travel at hundreds of miles per hour, have low amplitudes out at sea, but can become very high when approaching shore

17.  http://www.funkybiology.com/Destructive_F orce_of_Tsunami_Waves_mov.mov http://www.funkybiology.com/Destructive_F orce_of_Tsunami_Waves_mov.mov  http://www.youtube.com/watch?v=dJBS94G Vyuo http://www.youtube.com/watch?v=dJBS94G Vyuo  http://www.youtube.com/watch?v=BAuWa77 vYDU http://www.youtube.com/watch?v=BAuWa77 vYDU  http://www.youtube.com/watch?v=z- t5qe_VSEA http://www.youtube.com/watch?v=z- t5qe_VSEA  http://www.youtube.com/watch?v=wHtvA- lIksU http://www.youtube.com/watch?v=wHtvA- lIksU  http://www.youtube.com/watch?v=sBkMLYU yUZg&safe=active (new) http://www.youtube.com/watch?v=sBkMLYU yUZg&safe=active

18.  Longitudinal wave  Sound travels as a region of compressed air  The areas in between compressed regions are called “rarefactions”  Speed of sound is about 340 m/s in air  Like any wave the speed depends on the medium

19.  Frequency of a sound wave affects the “pitch” or how we hear a sound  Higher frequency, higher the pitch  Humans can typically hear pitches ranging from 20 Hz (infrasonic) to 20,000 Hz (ultrasonic), but that range diminishes as you age… typically at the high end  Loudness of a sound is affected only by amplitude

20.  http://www.cbu.edu/~jvarrian/applets/dopp ler1/doppler.htm http://www.cbu.edu/~jvarrian/applets/dopp ler1/doppler.htm  http://www.youtube.com/watch?v=AXhRmv1 mrs4&safe=active http://www.youtube.com/watch?v=AXhRmv1 mrs4&safe=active  Hearing test  http://en.wikipedia.org/wiki/52- Hertz_whale http://en.wikipedia.org/wiki/52- Hertz_whale  lonely whale  http://www.youtube.com/watch?v=h5l4Rt4O l7M&safe=active http://www.youtube.com/watch?v=h5l4Rt4O l7M&safe=active  Hearing test

21.  Waves From an object that is approaching have short wavelength, which means they have a higher freq. And a higher pitch  waves coming from an object that is moving away from you have a longer wavelength and therefore a lower freq, and lower pitch  Cars approaching and leaving

23.  Sometimes the source of a wave can travel faster than the waves it is creating  http://www.youtube.com/watch?v=6o0zmaf xTmE&safe=active http://www.youtube.com/watch?v=6o0zmaf xTmE&safe=active  Can be easily seen with a speed boat  http://www.youtube.com/watch?v=2Sv4o4Kk tm4&safe=active http://www.youtube.com/watch?v=2Sv4o4Kk tm4&safe=active  Sonic boom created when a object or plane breaks through the sound barrier

25. Standing waves Stationary wave caused by interference between a wave and its reflection – Two waves of equal amplitude and wavelength pass through each other in opposite directions. Nodes – stationary points – Where waves our “out of phase” --- crest lined up with trough Antinodes- points of largest amplitude – Where waves are “in phase” - crest lined up with crest Standing Wave in Water Standing wave demo Standing waves created by speaker Swimming pool When an object is forced into vibrating at one of its natural frequencies, it vibrates in a manner such that a standing wave is formed within the object.

26. Tacoma Narrows Bridge http://www.youtube.com/watch?v=3mclp9Q mCGs http://www.youtube.com/watch?v=3mclp9Q mCGs

27. Resonance When an object vibrates at its natural frequency, a dramatic increase in amplitude occurs Resonance happens when a standing wave is created Break Glass w/ voice? Mythbusters

28. Beats Two tones of slightly different frequency are sounded together. This produces a fluctuation in the loudness of combined sounds. – adfs Amount of beats per second is equal to the difference in frequencies. – Two tuning forks…. One 340 Hz another 310 Hz are sounded together. Beats will occur at a frequency of 30 Hz