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Homework Help: Demonstration dips his wettened fingers into molten lead

  1. Nov 2, 2005 #1
    Just reading a textbook and came across this interesting question:

    "a daring lab instructor in a demonstration dips his wettened fingers into molten lead (327C) and withdraws them quickly without getting burned. How is this possible?"

    I was thinking simply that the water on the fingers will absorb the heat and since he withdraws his fingers quickly it wont reach his hand but this sounds a little shady...any other ideas on this?
  2. jcsd
  3. Nov 2, 2005 #2


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    Gold Member

    The water vaporizes to form a protective sheath.

    Last edited: Nov 2, 2005
  4. Nov 2, 2005 #3


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    Science Advisor

    The cold water absorbs the heat before the fingers do. It only lasts a very breif time. Dessert chefs do something very similar when making various candies. They test what stage their molten sugar is at (softball, hardball, soft crack hard crack etc...)by dipping their hands in water and then grabbing a small portion of the molten sugar with their two fingers. They immediately take the molten sugar and put it under the water again to get the feel for the sugar. It doesn't burn you even though the molten sugar is usually well over 300 degrees.
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