# Newton's Law of Cooling & Specific Heat Capacity

1. Jun 21, 2012

Newton's Law of Cooling basically states (I believe):
TObj = (TInital-TEnv)ekt + TEnv
where k is a property of the material.

In the equation:
Q=mCΔT
Specific heat capacity, C, is also a material property.

So here's my question:
Is there a relation between Newton's Law's k and the specific heat capacity of the material?
Also, I'm in a debate whether Newton's Law requires a draft to be accurate. Any information either way would be useful.

Thanks

2. Jun 22, 2012

### sankalpmittal

Yeah ,

http://www.tutorvista.com/content/p...at-and-thermodynamics/newtons-law-cooling.php

Yeah , it requires draft to be "more" accurate....

I would like other members as well to post their views...

3. Jun 22, 2012

### nasu

The general law states that the rate of heat transfer is proportional to the temperature difference and the area of contact.
Solving for a body cooling in some environment with fixed temperature produces an expression like the one you propose. Only that for cooling the exponent is negative. Your solution correspond to a temperature that increases indefinitely in time, unless you assume k<0.
Indeed the time constant in the exponent depends on the specific heat capacity of the body (and its mass too).

4. Jun 22, 2012

### haruspex

It's not that it requires a draft, merely that what it's in contact with has effectively a constant temperature. In air, some forced draft, rather than mere convection, will certainly be needed. But in principle it could be encased in a solid with a very high specific heat.
The concept of a Tobj also suggests the object maintains a uniform temperature, which would imply a very high conductance. In practice, the temperature profile through the object will tend to change over time. It is probably not right to take an average temperature and expect the equation to work exactly, but I could be wrong.

5. Jun 26, 2012