Originally Posted by foodguy
i smell a column coming on. i think steady and even are very closely related. the heat is retained and radiated (theoretically, anyway) across an even surface, rather than a quick heat/cool you get with a good conductor such as copper. can anyone give me a good explanation of this so i don't actually ahve to do my job?
They are related, but not closely, and the terms are fairly imprecise.
To me, even heating is a reasonably-explainable phenomena: A material with a high heat transfer coefficient will conduct heat within itself more rapidly, thus all points of such a material will respond faster to a change in temperature, all other things being equal. Across the surface of a pan, this will also be affected by the material thickness (a thin pan will have a less even heat distribution than a thick pan).
Steadiness, which sounds more like a pan's ability to maintain a constant* output of heat despite variations in the amount of heat going into the pan (Matt's oven cycling) is likely more related to heat capacity, which is the amount of energy it takes to heat up a unit of a material one degree -- you have to pump a lot more energy into certain materials to heat them up; thus, they have a greater store of energy to re-radiate out when the amount of energy flowing into them decreases.
They are related in that if you have a material with a really high heat capacity but also high conductivity, it may have a lot of stored energy but dump it fast. A material with a really high heat capacity and poor conductivitity will store a lot of energy and dump it slowly, and lastly, a material with a low heat capacity but high conductivity will store limited energy and dump it fast.
This will be confused by differing radiative heat transfer from different materials -- radiative heat transfer is not how you used it above, that's conduction (transfer by contact or within a substance), rather, radiative transfer is by energy radiating from a body (think of IR warming lamps -- they heat by IR radiation),