Can hot water freeze faster than cold water?

[Wombat]

Originally posted by Elie

From my understanding about heating water in microwaves is this...
A microwave heats an element from the inside out

This is not true. It excites the water molecules. A microwave will heat wherever the waves can penetrate, outside in.

Anyway, this glass layer is not being broken keeping the temperature of the water higher than the natural boiling temperature of water.
After you superheat water and break that thin glassy layer, all hell breaks loose because the temperature underneath that surface is super hot, an awesome explosion will occur.

Also incorrect. All the water is not, but the energy of the heat is not disturbed. It just needs a trigger to react. This is similar to a super-solution.

[Greebe]

I've seen similar also happen while using an industrial grade ultrasonic cleaner. When the lid was removed the water solution would instantly burst into a boil with explosive force and burn the h*ll out of any exposed skin.

Seing this was purchased on my account (my needs only) anyone who used it got one heck of a wake up call when it happened. Seems everyone knows it all and doesn't bother reading instructions/hazardous warnings

[Greebe]

The operating frequency of a microwave oven is 2.54gHz specifically because it excites water molecules. The reason you've heard they heat from the inside out story is due to some foodstuff exhibit the pizza sauce factor. The outer layers have less water content and thus heat slower than the inside temps. There was a study done back in the '70's (goverment grant stuff) to find out why a pizza could be warm on the outside and yet burn your mouth off inside. The bread base/cheese topping acts as insulation keeping the internal temps piping hot.

[Paddy]

[Drizzt]

dP / dT = H / [ (v2-v1)*T ]