heat retention of materials

[manhattan]

its been many years since i studied physics and am having trouble getting my head around the subject of heat retention in materials.

 

i understand that the specific heat capacity of a material is the measure of energy required to raise 1g of a substance by 1degreeC. If the amount of energy required to change a materials temperature can be calculated by /\Q=mc /\t does this mean a material with a high specific heat capacity is a good insulator?

 

does this also mean that an insulator is good at retaining its heat?

[m4rc]

No. There are many examples of good insulators with a low heat capacity. For example, many thermos bottles have a vacuum layer which would have a very low heat capacity but provides excellent insulation.

 

A good insulator will have a low thermal conductivity which is different than the heat capacity.

 

The heat capacity is a measure of how much heat an object can absorb, while the thermal conductivity is a measure of how much heat an object can transmit through itself.

[swansont]

Two different concepts here: heat capacity and thermal conductivity. heat capacity, as you note, tells you how much energy you need to raise the temperature. Thermal conductivity tells you how much heat will conduct through a temperature gradient. They do not necessarily correlate well with each other, unless you have an ideal gas.

 

edit: d'oh! m4rc snuck in while I was composing my answer.

[manhattan]

thanks for your quick replys both of you. This looks like a great forum you've got here, glad i stumbled upon it