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Q & A: Sight and Sound

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Most recent answer: 10/22/2007
Q:
Explain why you see an airplane before you hear it.
- Anonymous
A:
Simply put, the reason that you can see an airplane before you can hear it is just because light travels faster than sound. 

In air like our atmosphere, the speed of sound is about 330 meters/second (or about 740 miles/hour) but the speed of light is 300,000,000 meters/second (or about 186,000 miles/second).  So light that bounces off the plane reaches your eyes much, much, much faster than the sound that the plane makes can reach your ears.

(This is the same reason that you can see lightning before you can hear the thunder it creates!)

-Tim


(published on 10/22/2007)

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