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Article: Why does a droplet of water dance on a really hot pan?
- Article from:
- The Boston Globe (Boston, MA)
- Article date:
- December 3, 2007
- Author:
CopyrightCopyright 2007 The Boston Globe. Provided by ProQuest LLC. (Hide copyright information)
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Ask Dr. Knowledge
This is a pretty subtle phenomenon that sometimes goes by the
name of the "Leidenfrost effect." Here's how it works:
If the pan is not too hot, the water lands on the surface and
absorbs heat. That heat will make it evaporate or, if the su rface
is hot enough, may even make it boil. Either way, the important
thing is that the water makes direct contact with the pan and stays
in contact.
If the pan is very hot, then as the drop of water hits the
surface some of it can boil off rapidly, forming a sort of cushion
of steam that insulates the droplet from the hot surface. The water
droplet is now in contact with hot steam, which is much less able to
heat the water than the hot ...