Newton's Law of Cooling & Specific Heat Capacity

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Discussion Overview

The discussion revolves around the relationship between Newton's Law of Cooling and specific heat capacity, exploring whether there is a connection between the material property represented by the constant k in Newton's Law and the specific heat capacity C. Participants also debate the necessity of a draft for the accuracy of Newton's Law in practical applications.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that there may be a relationship between the cooling constant k in Newton's Law and the specific heat capacity C of the material.
  • Others argue that Newton's Law requires a draft to be more accurate, particularly in air, while suggesting that a solid with a high specific heat could also maintain a constant temperature.
  • A participant notes that the general law states the rate of heat transfer is proportional to the temperature difference and area of contact, and mentions that the time constant in the exponent of the cooling equation depends on specific heat capacity and mass.
  • One participant questions whether specific heat capacity can be determined using Newton's Law of Cooling, given that both k and C are unknowns in the equation k=K/mC.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of a draft for the accuracy of Newton's Law, and there is no consensus on the relationship between k and specific heat capacity. The discussion remains unresolved regarding these points.

Contextual Notes

Participants highlight that the assumptions regarding temperature uniformity and the nature of contact with the environment may affect the applicability of Newton's Law. There are also unresolved mathematical steps concerning the determination of specific heat capacity.

Bradley Sigma
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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
 
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Bradley Sigma said:
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

Yeah ,

http://www.tutorvista.com/content/physics/physics-iii/heat-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...
 
Bradley Sigma said:
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?

Thanks
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).
 
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.
 
sankalpmittal said:
Yeah ,

http://www.tutorvista.com/content/physics/physics-iii/heat-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...

Newton's Law of cooling can also be stated as
ln(TObj-TEnv) = kt+c
k can therefore be found by finding the gradient of the trend line of the natural logarithm of the difference in temperature between object and the environment as a function of time.
However, would I be correct in thinking that something similar cannot be done to obtain the specific heat capacity, as your link states k=K/mC, for which the mass can easily be found, but as both K and C are unknown, they cannot be determined to a specific value. I know that there are other ways of determining specific heat capacity, I'm just wondering if it can be done using Newton's Law of Cooling.
 

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