The physics of water?

Question

I know that ice isn't as dense as liquid water, hence it floats in liquid water. What I don't understand is whether water takes up more volume in solid or liquid form. If you have ice in a cup of water the solid has displaced the same amount of water as it would if you just tipped that amount of liquid water in. This is the reason a glass wont overflow if the ice in it melts. However when it comes to global warming, if the icecaps melt, wont that liquid water just displace the same amount as it would when it was in solid form as it was already displacing water when it was solid. I read that liquid water only takes up 92% of the volume it did when it was ice but if this were true then wouldn' the sea level drop? Or isn't this taking into account the amount of ice actually sitting on land in Antartica and Greenland. Is what I've written write? If not, could you please explain to me in detail what actually occurs.

I mean, is what I've written right, not write.

Answer 1

There are two types of ice reserves:
1) Floating ice - ice bergs, and frozen sea
2) Ice on land mass - such as Greenland and Antarctica.

> Icebergs - have volume above and below water as ice is less dense than water - when ice melts there is no net change in sea level - due to Avogadro's principle, assuming the density of ice melt = density of sea water. Upthrust = volume of liquid displaced = weight of iceberg = weight of water when melted.
In fact salt water is denser than melted ice if the ice came from snowing or rain. So one could assume some sea-level rise due to this difference. If the ice comes from frozen sea water and the brine is incorporated into the ice then there will be no difference.
> Ice on land-masses - this is unconstrained by sea-level - once it melts the land it was sitting on rises and so does the sea - Antarctica and Greenland hold huge amounts of ice.

Answer 2

Using the equation that density equals the mass over the volume, is the mass stays the same, which it should and the density becomes smaller, to equal this out, the volume that the liquid takes up shall increase. But since the polar ice caps are made from pure water, if they were to melt, the water will float on the top and add more water to the oceans, but in doing this, the sea level would only rise a few centimeters because the volume of the ice is greater than it would be melted so the volume of the water in the ice displaced over the whole earth would BARELY raise the sea level, so dont worry about it. It is that and the fact that the Earth has its own way of healing itself.

Answer 3

When water freezed, it expands a bit. That's why ice floats. It weighs less than an equal volume of water.

If the poles melt (or partially melt), they will raise the level of the oceans. That's because the ice at the both poles covers a vast area, (larger than North America, I think) AND they sit well above sea level. Parts of Antarctica has ice over a mile thick, and sits on dry ground, remember.

Think of it this way on a small scale. Take a kid's wading pool that is maybe 4 feet across. Add some rocks here and there to serve as continents, then fill the pool with water until its 6 inches deep. There's your scale model earth. Then balance a block of ice that's 1 cubic foot in size on a rock, and let it melt. The water level will rise, right?

Does that help?

Answer 4

I think that behind your question is the idea that if the ice caps melt and the sea level rises a bit so what
If the ice caps melt the big change will be the earths climate system which is driven by temperature differences over the globe and the difference of heat reflected from white ice and dark sea water
If the differences become less we really don't know what the results will be, but I would rather not find out or let my children suffer

Answer 5

Water expands when it freezes, and ice shrinks when it melts. When the icecaps melt the biggest problem won't be from adding to sea level but decreasing the salinity, saltiness, of the oceans. The sea levels probably would rise from the ice above water too.

Answer 6

Yes ice is technically more dense than water, so when it floats in water it displaces the same amount of water because only 76% is under the water surface.
As it melts the other 24% then mixes with the water.
As for Global warming, you do need to take into account things like glaciers and ice on land.

Answer 7

Yes, it's the Antarctic and Greenland ice caps that are the problem.

Answer 8

Water expands in volume when it freezes...Simple as that!