You’re on the moon, skipping around, and your radio breaks. What would be the best way to communicate this problem to your friend, who is also skipping around on the moon: yelling or flashing a light? Why?

Video Transcript

This is College Physics Answers with Shaun Dychko. When skipping around on the Moon, where there's no air by the way and your radio breaks, your best bet is to flash a light to get attention from your friend and get some help because yelling will not be perceived by your friend since sound requires a medium through which to propagate. So there's no air on the Moon and so that means this sound transmission would be very inefficient it would happen supposedly a little bit because the sound could go through the air of your helmet into your spacesuit and then vibrate the ground and then vibrate the spacesuit of your friend and then that would vibrate the air inside their helmet and then that air vibrating would impact your friend's ear and they might hear that way but the yelling would have to be super, super loud and the friend would probably barely hear it anyway, if at all. So flashing a light is the best way to get their attention because light does not require a medium to go through so it can travel through the vacuum between you and your friend.