"A kid lets go of a helium balloon and watches it rise slowly up to the sky. Does it:
a) rise until the air pressure is low and the temp. is cold enough for the helium to compress and the balloon sinks, then when it falls back to regular air pressure and temp. it rises again and it continues in a loop (up and down) until ultimately it falls to the ground when it runs out of helium?
b) rise higher and higher until it floats/explodes in space?
c) explodes from the low air pressure, then the torn rubber/plastic falls slowly to the ground?
I've wondered about this since I was a kid..."