1. Sound Waves

2. Refresh: Types of Waves Longitudinal or compression – vibrate parallel to velocity. ex. Sound Longitudinal or compression – vibrate parallel to velocity. ex. Sound Transverse – vibrations perpendicular to velocity. ex. Light and water waves Transverse – vibrations perpendicular to velocity. ex. Light and water waves

3. Soundwave velocity Air (@ 20 0 C) – 343 m/s Air (@ 20 0 C) – 343 m/s Water – 1482 m/s Water – 1482 m/s Seawater – 1522 m/s Seawater – 1522 m/s Steel – 5960 m/s (trains) Steel – 5960 m/s (trains) –1 mile = 1600m Denser = Faster! What type of relationship is this? Directly Proportional of course!

4. Reminder: υ =f λ The velocity of a wave determines other properties as well… f and λ. The velocity of a wave determines other properties as well… f and λ. v = ? v = ? V determined by medium V determined by medium

5. Visualizing Sound waves Sound waves create rings that move away from the wave source. Sound waves create rings that move away from the wave source. Each ring has a λ Each ring has a λ from the next ring λ is equal to λ is equal to all others if the source is stationary.

6. Moving wave sources When a wave source moves, the wavelength and frequency becomes distorted. When a wave source moves, the wavelength and frequency becomes distorted. λ becomes a different length depending on the observer’s λ becomes a different length depending on the observer’sposition. υ

7. Moving wave sources #2 The faster the wave source’s velocity, the more distorted the λ. The faster the wave source’s velocity, the more distorted the λ. Source moving at the speed of the wave υ

8. Moving wave sources #3 Low frequency observed High frequency observed λ λ Doppler Effect – apparent shift in frequency of a wave caused by a moving wave source. υ

9. The “Sound Barrier” 1 st broken by Chuck Yeager (US Air Force test pilot) in the Glamorous Glennis… a rocket plane named after his wife. 1 st broken by Chuck Yeager (US Air Force test pilot) in the Glamorous Glennis… a rocket plane named after his wife.

10. The “Sound Barrier” Usually, a “cloud” forms as water vapor condenses under the extreme pressure. Usually, a “cloud” forms as water vapor condenses under the extreme pressure. υ A sonic “BOOM” is an extreme example of Doppler A sonic “BOOM” is an extreme example of Doppler The wave source moves faster than the wave of sound The wave source moves faster than the wave of sound A “cone” of compression results as the air tries to get out of the way. A “cone” of compression results as the air tries to get out of the way.

11. F-14 Tomcat and F-18 Hornet going Supersonic – MACH 1

12. Video of sonic BOOM!!! 2006-6-5_Sonic_Boom.MPG 2006-6-5_Sonic_Boom.MPG 2006-6-5_Sonic_Boom.MPG SupersonicF14_2.mpeg SupersonicF14_2.mpeg SupersonicF14_2.mpeg

13. Interference Destructive Destructive Constructive Constructive + = + =

14. Interference#2

15. Resonance – “resound” Just like constructive interference, resonance occurs when 2 vibrations occur in phase, producing a bigger vibration. Just like constructive interference, resonance occurs when 2 vibrations occur in phase, producing a bigger vibration. http://video.google.com/videosearch?sourceid= navclient&hl=en-GB&rlz=1T4GZEZ_en- GBUS304US304&q=Tacoma%20Narrows%20Bri dge&um=1&ie=UTF-8&sa=N&tab=wv# http://video.google.com/videosearch?sourceid= navclient&hl=en-GB&rlz=1T4GZEZ_en- GBUS304US304&q=Tacoma%20Narrows%20Bri dge&um=1&ie=UTF-8&sa=N&tab=wv# http://video.google.com/videosearch?sourceid= navclient&hl=en-GB&rlz=1T4GZEZ_en- GBUS304US304&q=Tacoma%20Narrows%20Bri dge&um=1&ie=UTF-8&sa=N&tab=wv# http://video.google.com/videosearch?sourceid= navclient&hl=en-GB&rlz=1T4GZEZ_en- GBUS304US304&q=Tacoma%20Narrows%20Bri dge&um=1&ie=UTF-8&sa=N&tab=wv#

16. Use of sound technology Thunder and lightning! 5 sec ~ 1 mile. Thunder and lightning! 5 sec ~ 1 mile. Sonar – using the echo of a soundwave to determine distance and position of objects. Sonar – using the echo of a soundwave to determine distance and position of objects. http://earthguide.ucsd.edu/images/aldemo/ swf/sonboat.html http://earthguide.ucsd.edu/images/aldemo/ swf/sonboat.html

17. Echolocation - bats See: Ben Underwood

18. Refresh: Vibrations A “vibration” can be compared to a pendulum swinging back and forth as its energy is transformed from KE to PE to KE. A “vibration” can be compared to a pendulum swinging back and forth as its energy is transformed from KE to PE to KE.