A Matter of Tremendous Gravity. Or Not.
TOM: My answer was a helium balloon.
RAY: There you go. You're right. That's the answer. Any balloon with lighter-than-air gas, such as helium or hydrogen, would work for an answer. Because on the Earth it wouldn't weigh anything on the scale, right?
RAY: In fact if you were standing on the scale and holding a big enough helium balloon --
TOM: It could make you weigh less.
RAY: It could make you weigh nothing. If you tried to put it on the scale it wouldn't register because it would float away. But on the moon, because there is no atmosphere, in addition to being not much gravity, there's nothing for the balloon to float on. Therefore, if it doesn't explode, it'll sit on the scale and it'll actually weigh something, whereas on the earth it doesn't weigh anything.
So do we have a winner?
TOM: Yeah, we do have a winner. The winner is Rochan Sharusta, from Kathmandu, Nepal.
[ Car Talk Puzzler ]