1. Sound Chapter 14 Physics Principles and Problems Zitzewitz, Elliot, Haase, Harper, Herzog, Nelson, Nelson, Schuler and Zorn McGraw Hill, 2005

2. Sound Wave - pressure variations that are transmitted through a medium. http://moscow.cityu.edu.hk/%7Ebsapplec/Fire/Image222.gif A vibrating object (i.e. a bell, your voice box) moves forward and strikes the air molecules, thereby compressing them (increased pressure). When the object moves backward the air molecules are no longer compressed (decreased pressure).

3. We perceive sound when the sound waves strike the tympanic membrane in our ear. This starts to vibrate to the particular sound wave frequency. Our nerves then send this information to our brain. http://scienceblogs.com/retrospectacle/upload/2006/06/sound%20wave.JPG

4. Pitch - the tone of the sound we hear. Sound wave frequency and pitch are directly related. Sound wavelength and pitch are inversely related. Most humans cannot hear sounds below 20Hz and above 16,000Hz. Each musical note have a different pitch and therefore different frequency (middle C = 262Hz) http://moscow.cityu.edu.hk/%7Ebsapplec/Fire/Image231.gif

5. Loudness - refers to the amplitude of the sound wave. The unit of measure for loudness is the decibel (dB). Most people perceive a 10dB increase as being twice as loud as the original sound http://www.cmp.org.nz/images/sound-level-chart.jpg

6. Doppler Effect - the change in frequency (and pitch) of sound due to the movement of either the source (i.e. an ambulance) or the detector (i.e. you) http://ircamera.as.arizona.edu/NatSci102/images/doppler.jpg

7. When the detector has no velocity (v d = 0) f d = f s (1/ 1-v s /v) f d = frequency perceived by detector f s = frequency of source v s = velocity of source v = velocity of the wave

8. When the source has no velocity (v s = 0) f d = f s (1 - v d / v) f d = frequency perceived by detector f s = frequency of source v d = velocity of detector v = velocity of the wave

9. Great web site for waves: http://www.physics.colostate.edu/users/pavol/ga_oscillations_waves.html http://www.cinnamonrainbows.com/weeklypic/HUGE%20Wave.jpg