4/1/09
Post date: Mar 30, 2009 11:46:43 PM
Bell Ringer: Imagine you are floating on a boat near a dock. You have a stopwatch and a meter stick with you. How would you calculate the speed of the waves as they go by you?
Wave speed lab
Calculating the speed of waves on a spring. Due Thursday.
Wave speed
Depends on what type of wave
Sound waves move faster than water waves
Depends on properties of the medium
molecules that are closer together transmit waves faster
Gases - farthest apart, so slowest waves
Liquids - closer together, so faster waves
Solids - closest together, so fastest waves (try tapping on desk with ear pressed to it... do you hear it better with your ear to the table or the one that's not on the table?)
Light has definite speed = 300,000,000 m/s in a vaccuum.
Doppler effect
Waves move at a certain speed, regardless of how fast the wave source is moving
Waves ahead of source get squeezed together for a higher pitch, waves behind get spread apart for lower pitch
Page 522 for picture and explanation
Frequency changes when the object making a wave is moving
Example
Sound waves
chime moving forward and backward
plastic tubes
Light waves
red shift
15.2 Review (pg. 523: 1-9) due Thursday