Why are weather balloons filled with Helium?

Hydrogen atoms are much smaller than helium atoms, so they will permeate the latex much quicker. This will lead to the balloon coming down much sooner.

Both are apparently used. Helium has had the edge for safety reasons, but the cost is bringing hydrogen back into the game. Here’s an example of the use of hydrogen.

@Harp : hooray!
@Eambos: Ah, but Hydrogen molecules are diatomic.

My chemistry skills have failed me. I knew that they were diatomic, I just thought that the atomic radius was still smaller than that of a single helium. Must refresh knowledge!

@Eambos: That’s okay, heck, as @Harp demonstrated, I could’ve just googled the entire question.

I had no idea that you even COULD use hydrogen. I was just gonna say “Um… so it can float?” Ha.

@mangeons : they used to use it all the time, until… http://www.flickr.com/photos/octopusgallery/422299939/

Probably because hydrogen is so very flammable.

Oh, the humanity!

Hindenburg

Oh, Schenectandy. Would you have us explode in Antarctica?

http://www.cartoonstock.com/lowres/bgr0029l.jpg