School kids measure distance to the Moon

The students analysed an mp3 recording of the conversation between Neil Armstrong on the surface and ground control in Houston in which he utters his famous “one small step” speech. The recording is available on the NASA website.

They noticed an echo on this recording in which sentences from Earth are retransmitted via Armstrong’s helmet speaker through his microphone and back to Earth. They used the open source audio editing program Audacity to measure the echo’s delay