Stuck ice Cubes

After formation of ice in a ice tray, why it is difficult to take out the same from tray altough the volume of water decreases after ice forming.
- Hiren Doshi (age 26)
Gujarat,India

Your reasoning makes sense but you have a fact wrong. Ice has a larger volume than liquid water. So when it freezes in an ice cube tray, it can get pretty well stuck, depending on what part freezes first.

Mike W

Lee H.

(published on 10/22/2007)

This is exactly right, so, why is it that we’re scared of icy continents melting (due to Global Warming) and us all drowning??
- Seb (age 16)
Sydney, Australia

If much of the ice sitting on the Antarctic continent or on the Greenland Shelf melts, water will pour into the oceans, raising their level. Most people will presumably get out of the way in time to avoid drowning (this will all take some time to happen), but an enormous fraction of the Earth's population would be homeless. In addition, the warmer oceans may support more powerful storms, with the resulting damage. The dissolved CO₂ will turn the oceans too acidic and kill off the corral reefs, and all the life they support, even aside from the temperature changes. It might make more sense to switch to small efficient cars, public transportation, etc.

Mike W.

p.s. I guess you're thinking about the arctic ice, which mostly floats and will not directly affect the sea levels much. As it melts, it might shut down the Gulf Stream, but that's another story.

By the way, there is an additional effect due to the thermal expansion of ocean water when it warms up.  There are various estimates but it seems that about half of the ocean level rise could be attributed to this effect.
LeeH

(published on 10/22/2007)