Billy_Bob
Diamond Member
If you did this in a vacuum the temps would be the same.now, I agree with this write up!let's say it was heated on a gas stove, and now you suspend it in flat in normal temperature air, does the pan evenly warm the air around it. If I took two thermometers, placed one two inches from the top surface and one two inches from the bottom surface, would they all read the same temperatures as the pan cools down?no, just the hot pan. no water.Both. Radiation and convection play a part, plus you seemed to have forgotten about conduction.
Gravity is the mechanism behind the macroscopic movement of mass that carries the energy in convection. Radiation and conduction are microscopic processes, one that doesn't need close physical proximity and one that does.
I have a feeling that you are over estimating the amount of temperature differential between the top and the sides of the pan. Where you actually thinking of a pan of boiling water? In that case it is the steam which carries the energy to the heat receptors in your hand.
In that case I would suggest using a sphere of some sort so that physical shape does not interfere with your perception. A pan has more surface area facing upwards than to the side. Are you talking about a pan that is actively being heated, or one that has been warmed and is now cooling by the three mechanisms in a passive fashion? If it is actively being heated, by what kind of of source. Gas flame, electric element, or electric induction?
The volume of air inside pan would heat the quickest because it has the most exposure to conduction and radiation. That would initiate convection. The air above the pan would be warmer than the air below because warm air is less dense and gravity replaces it with cooler air, pushing the warm air up.
Two inches below the pan, air would only be warmed by radiation. The air in direct contact with the bottom would rise before much energy could diffuse downward. The sides would be somewhat warmer because the energy would have a better chance to diffuse outwards.
It would be interesting to see the convection pattern of air flow. I bet the pan would cool more unevenly that its shape would suggest.
I still think a cannonball would give cleaner results with less complications due to shape and convoluted air flows.
We could turn the pan upside down suspended. Again, the heat would still be greater on the top.
I could do the cannon ball as well. then you could put four thermometers and read four points. I don't think again, they would be equal in temperature reading.