Last edited by Ron C; 06-28-2012 at 10:05 PM.
Ron C. / Chicago-area
2012 Crystal Red Tintcoat Volt C8794, acquired 11/08/2011
Just throwing my guess in this mix...
...I suspect it has to do with the polar bonding of the Oxygen of the (H2O) with each other. Oxygen has extra pairs of electrons that allows it have a weak-polar bond with a neighboring H2O molecule. In cooler water, the molecules are more calm and have bonded with each other, while in hotter water, more molecules are more active and less have formed the bond.
When heat is taken out to make ice, water forms in a rigid crystal structure such as ice where it can trap air. Hence, it is obvious that bonds are broken and re formed inorder to make ice.
In the hotter water, the molecules are already separated so many can simply form the bond and fall into place, on the other hand, cooler water needs to break existing bonds and then reform those bonds once they fall into the correct place. The breaking of the bond takes energy, and the release of it gives off the same energy, so it should not take any more cooling to get the same job done, but you need to wait until those bonds have finished breaking, have the molecules move into the correct place, and then setting the new bond. (which takes more time.)
Another factor that may explain it on this similar thinking is that energy is needed to break and set the bonds in order for water to form into ice. A cup of warmer water has more available energy that can be used to break the bonds so those "free-er" molecules can fall into the proper place to set the bonds to make ice; once the new bond is set, energy is release that another molecule to use to break free, settle, create their new bond, release the energy, and repeat.
Last edited by KyleH; 06-29-2012 at 04:07 PM.
I'm not completely convince by your arguments. The following are my explanations on why ice forms on top then outside in...
...Water is rather unique where it's solid form (ice) is less dense than its liquid (water) form. As ice is forming, it forms a crystal structure that can trap any existing air. Then, it simply floats up to the top, touches air, and fill completely with more air and hardens. In some cases, it gets caught light a suction cup along the side.
I think ice cubes form on top because it naturaly floats while it freezes. It only starts to form on the side because it is already touching the top and not float any higher.
...at least, that is my guesses.
Your morbid example is interesting, I would think if another twin (total of triplets) fell in, there is a "right amount" of exercising to have a slow controlled burn of calories that would make him reach hypothermia last--the idea of walking around and working out in a cold environment to stay warm. That is, in a blizzard, would a person standing in one place reach hypothermia faster than his twin walking in a circle around him? That I do not know; maybe an experiment has been done with lab animals?
There are more bubbles in cold water that makes it harder to freeze. Makes an insolation effect.
Last edited by VikAiRious; 07-22-2012 at 09:41 PM.
Simple - the warm water makes the freezer unit turn on, cooling the water faster.
That doesn't make much sense to me. I am assuming the phenomenon is true if you had the same mass and same volume but at the two different temperatures.
If you had that much "dissolved gases" that would exhibit insulation, then, if you cap both cups of water (one warm/hot, the other cold), wouldn't you be able to see less water in one of them when they get to the same temperature. I think would be easily disproven with a simple 5 min experiment by true professionals / experts. I have not tested it, but I would guess that the answer is more complex than gases.
Does anyone have a point of view from a chemists? I would be more intersted in what chemists say about this as well as the physicists.