Demonstration Manual

Heat

DHT15 - Crooke's Radiometer

Objective:

- To illustrate different absorption and reflection of radiation by different surfaces.

Apparatus:

• Crooke's radiometer
• Filament heater

Method:

Rapid rotation is produced by heat radiation of a filament heater. (Rotation is produced by a temperature differential between the silvered and blackened surfaces, resulting in a slight gas pressure difference between the two faces). The bulb has been evacuated down to a pressure of about 1 mmHg.

   Watch a Crooke's Radiometer video demonstration on Youtube

- Bill Nye the Science Guy explains the science of a radiometer