I remember seeing an elementary science school experiment measuring the water level of a beaker of water with an ice cube and the same beaker water level when the ice cube had melted. The level was the same after the ice had melted.
I remember being told that ice expands when it freezes and contracts when it melts, that the liquid water an ice cube displaces is the same as the amount displaced when it melts because the mass is the same.
So there is no change in level when ice melts.
Water is a very unusual substance even though we take it for granted. It exhibits things that run counter to what is expected.
So I did a little internet search "water level when ice melts" and as expected there are many many, too many to be counted explanations as to why water level is the same when ice melts. Here's one explanation found:
http://www.physlink.com/education/askexperts/ae389.cfm
Then I read again what was posted from this same fellow in the same paragraph:
It always troubles me to see posters make statements regarding physics that they only partially understand.
And I ask myself, Who is this guy?
And I answer to myself, I really don't want to know!
. . . I cringe whenever people state that melting icebergs won't raise sea level (they will) . . .
Do ice cubes in your Coke cause the liquid level rise if they melt before you get to drink it? (they won't)(water expands when it freezes, contracts when it melts)