[KenWittlief]

sciguy,

your analysis is excellent (esp for an electrical engineer :^)

the only point that doesnt sit right with me is you used the mass of your whole finger (1cm thickness) and if I understand the equation you used then which part of the finger is rasied to 120ºF? the surface of the side in contact with the metal, or the entire mass?

While the finger is in contact with the metal, there will be a temperature gradiant from the contact side to the back side, with the mass of the finger drawing heat away from the contact area.

The reason I ask is your answer seems pretty long - 66mS is only 1/15th of a second. My intuitive basis for this comes from experience, like licking your finger and tapping an clothes iron to see if its hot.

The other question is, what temp can we endure without being burned? 120ºF seems low. Tap water is usually 160 - 180ºF.