Proving the Speed of Sound

[Lorenzo M. Oliver]

Theory of operation:
Most of us can go to Google and search for the speed of sound and we find a number somewhere in the ballpark of  1125 feet per second. We take that number, use it and take it for granted to calculate a distance. Keep in mind that there are several factors that can affect the actual speed of sound, such as altitude, humidity, temperature, etc. which introduce errors to our ‘fixed’ value we obtained. But what if we wanted to prove what the speed of sound was instead of using some number we were able to find on-line?

The idea with this experiment is basically the same as sonar, except we are doing it with audible sounds instead. The idea is straight forward, you send a signal out and wait for an echo. The 'time' in-between when you send the signal verses receiving the signal can be calculated as the object distance. Since the Propeller controls all aspects of the  timing, the procedure is relatively simple.

http://forums.parallax.com/forums/default.aspx?f=21&m=453312