### Fireworks Video

Calculate the distance that the fireworks were away from the observation
point. The temperature on the observation night of June 28 was 64°F =
18°C. Using the equation^{1} for the speed of sound in air of *v* =
331.3 + 0.6*T* m/s where *T* is the temperature in degrees
Celcius yields

*v* = 331.3 + 0.6(18) = 342 m/s
Measure the time delay in the video between when you see the explosion
and when you hear the explosion. Since the speed that sound travels in air
is known (from above) the distance to the explosion can be found from the
equation

*d = vt*

Make at least 5 time measurements and find the average time.
Questions:

- What is the average time that you found?
- What is the distance to the fireworks explosions?
- Why don't you need to worry about how long it takes light to travel
this distance?

Fireworks Movie (QuickTime
format):

Small (5.4 MB)

Larger (23.2 MB)
Reference

^{1} Rossing, T.D., Wheeler, P., and Moore, R. The Science of Sound, 3rd ed. 2002
Addison Wesley. p. 47