Heat can be transferred from one place to another by moving a fluid; this form of heat transfer is convection.

Newton's law of cooling:

We will encounter this same exponential function in a w-i-d-e variety of seemingly unconnected situations.

Tsurf is the temperature of the surface of the object. Tsrnd is the temperature of the surroundings. T is the difference in temperature between the initial temperature of the object and its surroundings.


Automobile cooling systems:

Heating and air conditioning systems:

These may be "active" with a forced blower,

Or they may be "passive", using only "natural convection" due to the change in density and bouyance of warm air,

Convection currents in a pan of water on a stove speed up the heating of the entire pan of water.

Convection currents are set up in the empty space inside a wall,

The main thing insulation does is to stop these convection currents,

Most of our ordinary weather is the result of convection:


   Click here for an EXAMPLE.


Return to ToC, Heat Transfer

(c) 2002, Doug Davis; all rights reserved