Helium Balloon on the Moon

Most recent answer: 10/22/2007

Q:
hey if i put a balloon on the moon that has hellium wut happens? and if i pop it ? where does the hellium goes?
- david
Palisades Park High School
A:
The moon has no atmosphere to speak of. (There might be a few molecules knocked off from time to time by sunlight, but nothing much). So there’s no buoyant force on a balloon, whatever its contents. The helium balloon will just fall to the moon with the same lunar rate of gravitational acceleration (about a seventh of that on the surface of the Earth) as anything else.

If you pop the ballon, the helium will expand into space -- the molecules will go off in all directions. Some will bounce off the surface of the moon and head back the other way.

Tom

(published on 10/22/2007)