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 Originally Posted by Renton
The issue though is that the dousing with water seemed to change the way I felt the heat. The pan felt quite warm when I was holding it, but within 2-3 seconds of running the water onto it, it became almost too hot to hold.
I get you. My hypothesis is that the sensation is more to do with heat flow in your hand than with heat flow in the pan.
I have not experienced the sensation as you describe it, so I can't really explain it. If you tell me you did the experiment I described above and get the same results, then I'll certainly be discarding my hypothesis and thinking more deeply about the question.
Originally Posted by Renton
It's like the water somehow caused the pan to become a faster heat conductor, which makes no sense to me.
The rate of heat flows much more readily from the pan to water than pan to air. In that sense, the conduction is faster.
I'm sure that the thermal conductivity of the metal is ultimately a function of it's own temperature. I doubt that there is significant change in the temperature ranges we're dealing with. (I'm thinking molten aluminum would likely have a different rate than solid aluminum.)
Originally Posted by Renton
edit: The heat is definitely not evenly distributed in the pan at the moment I start running water on it. The bottom of the pan is likely many times hotter than the handle since it was on the burner. That is probably very relevant to this.
The main reason the handle is a different temperature is due to radiation and convection of the heat between the flame and handle. In a vacuum, the lack of air to transfer heat away from the pan would make the entire pan nearly the same temperature. Obviously, if you keep pumping energy into the pan, then it wont stay a pan for long.
It's complicated if the pan isn't empty, obviously. A pan boiling water will have a sharp temperature gradient on the bottom of the pan. The outside surface is exposed to flame at 1,950 C (assuming the fuel is methane aka natural gas, burning in air), but the inside surface is exposed to water at 100 C (assuming the water is boiling).
The temperature of the handle is difficult to guess for an arbitrary pan with arbitrary contents.
Based on my job working at an espresso shop, human skin can't maintain contact with metal over ~135 degrees F for more than about a second. (There's a thermometer in the aluminum carafe used to steam the milk at most shops. Obv. I experimented on myself and thermal tolerance in my fingers.)
I'd be shocked if you're touching metal over 140 degrees F for any duration w/o first degree burns (redness and sensitivity).
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