Physics 312 Lecture: "Transfer of heat by Conduction" May 14, 1998

Conduction is one mechanism by which heat can be transferred from one object to another (the others are convection and radiation).
When one end of a material is heated, the atoms there move more quickly (or vibrate more quickly in place); they jostle neighbors, and so forth, transferring energy through the material.
Thermal conductors move heat rapidly: they have large values of thermal conductivity "k"; thermal insulators transmit heat slowly: they have small values of "k"
Heat is transferred by conduction at a rate
```
           dQ/dt = - k * A * dT/dx
```
In a uniform medium, the gradient "dT/dx" may be replaced by "delta_T / length"
When several layers of material with different thermal conductivity are sandwiched together, the overall heat flow rate may be determined by calculating the overall "R-value"
```
                      R(tot) = sum of L/k
```
and using it in the equation
```
           dQ/dt =  A * delta_T / R(tot)
```

This lecture discusses material in Chapter 20 of Serway.