essential question why/how does the sound from a passing car change?
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Essential Question Why/how does the sound from a passing car change?. http://www.kettering.edu/~drussell/Demos/doppler/doppler.html. Stationary Source and Stationary Observers. http://www.kettering.edu/~drussell/Demos/doppler/doppler.html. Stationary Source but Moving Observer. - PowerPoint PPT PresentationTRANSCRIPT
Essential QuestionEssential Question
Why/how does the sound from a passing car Why/how does the sound from a passing car change?change?
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
Stationary Source and Stationary Observers
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
Stationary Source but Moving Observer
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
Moving Source but Stationary Observer
RaceRaceCarCar
Car Car PassingPassing
Doppler Effect
Moving Source but Stationary Observer
TrainTrainPassingPassing
DOPPLER (Δvelocity effect)
• A stationary sound source is emitting a 550 Hz buzz. You ride your bike toward the sound at 5 m/s… what do you hear?
DOPPLER (Δwavelength effect)
• You are standing on the side of the road as a police car approaches… it is traveling at 20 m/s and actually producing a 600 Hz siren… What do you hear?
http://kfty.com/weather/interactive/
Doppler RadarDoppler Radar
Another example of using the Doppler EffectAnother example of using the Doppler Effect
Sound…Sound…
Moving source causes a change in Moving source causes a change in frequency for stationary observers.frequency for stationary observers.
What else might the Doppler Effect affect?What else might the Doppler Effect affect?
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
Source Moving as fast as the waves it is making.
Object traveling FASTER thanObject traveling FASTER thanthe waves it is making.the waves it is making.
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
Source Moving FASTER than the waves it is making.
Source Moving FASTER than the waves it is making.
CrestCrestCrest Crest CrestCrest
+ Crest + Crest
Big fatty Big fatty CrestCrest
The Learning Channel – “Extreme Machines”
October 14 1947
Chuck Yeager – October 14, 1947Chuck Yeager – October 14, 1947
Source Moving FASTER than the waves it is making.
CrestCrestCrest Crest CrestCrest
+ Crest + Crest
Big fatty Big fatty CrestCrest
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
2193.16 miles per hour2193.16 miles per hour
http://www.mediacen.navy.mil/pubs/allhands/jan01/f14tomcat.jpg
http://www.ctrl-c.liu.se/ftp/images/AVIATION/MILITARY/USA/f14/f14-3.jpg
F-14F-14TomcatTomcat
dB – Decibels… better thought of as deci - BellsdB – Decibels… better thought of as deci - Bells
Loudness of SoundLoudness of SoundJet Engine at 30 m
Threshold of Pain,Siren, Loud Rock Concert
Lawn Mower
Vacuum Cleaner
Normal Conversation
Mosquito Buzzing
Whisper
Rustling Leaves,Normal Breathing
Threshold of hearing
140 dB
120 dB
100 dB
70 dB
50 dB
40 dB
20 dB
10 dB
0
0 dB to 10 dB0 dB to 10 dB
= 10 times louder= 10 times louder
= 10= 1011
10 dB to 20 dB10 dB to 20 dB = 10= 1011
= 10 times louder= 10 times louder
20 dB to 40 dB20 dB to 40 dB = 10*10 or 10= 10*10 or 1022
= 100 times louder= 100 times louder
40 dB to 70 dB40 dB to 70 dB = 10*10*10 or 10= 10*10*10 or 1033
= 1000 times louder= 1000 times louder
70 dB to 120 dB70 dB to 120 dB = 10= 1055
= 100,000 x louder= 100,000 x louder
15.2 dB to 48.4 dB15.2 dB to 48.4 dB
= 10= 103.323.32
= 2,089 x louder= 2,089 x louder
= 48.4 – 15.2 = 33.2= 48.4 – 15.2 = 33.2