An ice cube floats in water, with a liquid (less dense than ice) above it. When the ice cube melts will the water level go up, down or remain constant?
$\begingroup$
$\endgroup$
0
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
1
Without the second liquid above, the ice displaces a volume of water exactly equal to its own weight. After it melts, the ice becomes the same weight and volume of water, which is why the water level remains constant.
However, the upper liquid layer provides some buoyancy, so less of the ice cube is in the water than if there were no liquid above (i.e. it "sits higher" in the water). Therefore, the ice displaces less water than before but still contains the same amount of water as before, resulting in a rise in the water level after it melts.
answered Mar 25 at 22:34
-
3$\begingroup$ Note that if the upper fluid is very much less dense than ice, as is the air in the more common version of this question, then the buoyant force becomes negligible and we reduce to the more familiar "no change" answer. $\endgroup$– rob ♦Commented Mar 25 at 22:44