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Name: mary
Status: other
Age: 60s
Location: N/A
Country: N/A
Date: 1999 


Question:
Can one "warp" a pot/pan/skillet by transferring it directly from the fire to running cool/warm water on it? I know it makes grease fly everywhere, but could it not also warp it?


Replies:
The short answer: yes

Anytime one differentially quickly heats or cools any item, there are thermal stresses introduced into the item because heating or cooling, unless done slowly, tends to be uneven and has certain molecules moving more slowly than the others nearby. The result of the thermal stresses can do everything from shattering glass to warping or cracking of metal.

By the way, I have also seen in the past a huge fireball when someone removed a pot which had a grease residue only, from a flame, and placed the pot into a tub full of water. Needless to say, this can be very dangerous.....the better choice is to remove the source of heat, or remove the pan to an "off" burner and let it cool slowly.

Thanks for using NEWTON!

Dr. Rupnik


Generally, the thicker the pan, the more resistant it is to warping. I know from experience, however, that you certainly can warp a metal sheet (griddle, cookie sheet, saucepan) by the method you describe.

Richard E. Barrans Jr., Ph.D.


Dear Mary,

It depends on the degree of warping you expect. Indeed, if you pour cold water over one side of a hot flat pan, there will be a temperature difference through the thickness of the pan. This temperature difference will warp the pan but the warping is rather small and cannot be seen by naked eyes. You can see this, however, if you use instruments that can measure slight movements of the pan.

Splashing of oil is an unrelated phenomenon. Grease splashes because the water poured into a hot (over 100 C =212F) oily pan boils and evaporates violently. It takes some of the grease with it. This is the splash, which we particularly notice when cleaning the stove.

Dr. Ali Khounsary
Advanced Photon Source
Argonne National Laboratory
Argonne, IL 60439



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