Melting ice Level

Most recent answer: 10/22/2007

Q:
I know this may sound like a silly question, however a few of my friends and I were debating over this question for hours. So I’m looking for an answer to know for sure.

" Does the ice in a glass of water, make the water level higher after it melts?"
- Ricicha (age 22)
Hamlin, New York, USA
A:
Nope. The ice occupies a little more space when it’s frozen, but on the other hand a little of it sits above water level. The two effects just exactly cancel, so when it melts the volume it occupies is hust the same as the volume of the part below the water level when it’s frozen.

There’s a reason why the ’displaced water’ , the part of the volume below the water line, weighs just the same as the total weight of the floating object. The reason comes from making the total gravitational energy as small as possible.

Mike W.

(published on 10/22/2007)