Why under identical conditions, different materials warm and cool at different rates?

Question

is it because the kinetic energy varies in the materials??

Answer 1

You need to be a little more specific.  What does "ideal" mean?  Are you talking about equal masses, equal volumes, equal shapes, equal starting temperatures?  Sorry to make this more complicated but there are several things going on.  It is true the different materials have different thermal conductivities.  Even a given material can have rather different thermal conductivities depending on what temperature it is (liquid vs solid vs vapor and even different solid state phases).  The best answer is specific heat.  The heat capacity of a piece of material depends on the specific heat of the material in whatever condition it is in, the mass of the material, whether the material is in a calorimeter (so you can assume no heat loss or gain to the outside environment), and a "normal" heating rate (you are heating and cooling gradually rather than blasting it with laser beam that evaporates the surface or some other extreme thing).

Kinetic energy in a solid material could be considered vibrational energy as measured by temperature but that would not be the typical definition of kinetic energy.  The specific heat is really a measure of the electrical bonding energy between atoms or molecules.  If those bonds are relatively weak, a little thermal energy increase the vibration  alot, leading to a large increase in temperature.  If the bonds are very strong, it will take a lot of energy to increase the vibration enough to increase the temperature.

Hope this helps.

Answer 2

It's called thermal conductivity, and is a property of a material that defines it's ability to conduct heat. Aluminium has a high value, for example, and glass has a lower value.

this is an inherent property of the material, like its weight, it's color, it's electrical conductivity, etc.

Answer 3

the materials have different specific heats.  Specific heat is the amout of heat required to raise the temperature of 1 gram of a substance 1 degree celsius.