Convection in a Bunsen flame

Class practical

Visualizing convection currents in air.

Apparatus and Materials

• Compact light source (slide projector or other high intensity lamp can be used but needs dim-out), 100 W
• Bunsen burner
• Translucent screen
• LT variable voltage supply (capable of 8 A at 12 V)

Health & Safety and Technical Notes

Read our standard health & safety guidance

Procedure

1. Light the Bunsen and put it about 1/2 metre in front of the compact light source. Cast the shadow either on to the wall or on to a translucent screen.
2. Students should look at the shadow and discuss what they see.

Teaching Notes

The convection currents from the Bunsen flame can be clearly seen. The warm air rises up above the flame and falls down away from it.

This experiment was safety-tested in March 2006