water mass

[Ratlady]

Hi guys!

I'm trying to find an answer to a simple 'Did U Know' statement.

The statement is 'Did you know: hot water is heavier than cold water?'

Now it's all very well me quoting that to a 10-year old girl & impressing her with my knowledge - what if she says 'Why?'?!?!

My field of scientific interest is relativity & quantum mechanics, so I could explain it by way of the Einsteinian effects of the hot water molecules' increased speed resulting in increased mass, but I somehow suspect that's a teensy bit too complicated!

Any of you brainy people know the answer to this one? Any of you fancy making something up?? As long as it sounds good I don't care!

I'll pop back in now & then & see if anyone's thought of anything.

Thanks![/i]