Investigating Infrared Radiation

Question 1

What is a Leslie cube?

Answer 1

A hollow, watertight, metal cube whose four vertical faces have different surfaces e.g matt black paint, matt white paint, shiny and dull metal

Question 2

Describe how to investigate infrared radiation

Answer 2

1. Place an empty Leslie cube on a heat-proof mat
2. Fill Leslie cube with boiling water
3. Wait for the cube to warm up and hold a temperature against each of the four vertical faces of the cube. They should all be the same temperature
4. Hold an infrared detector at a set distance away from one of the faces and record the amount of IR radiation it detects
5. Repeat from all sides of the cube
6. Do the experiment more than once so they are repeatable

Question 3

What should your results look like after investigating infrared radiation using a leslie cube?

Answer 3

You should detect more infrared radiation from the black surface to the white one, and more from the matt surfaces than the shiny ones.

Question 4

How can you investigate absorption with melting wax?

Answer 4

1. Set up two ball bearings stuck to one side of a metal plate with solid pieces of candle wax. The other sides are faced towards a burning candle.
2. The plates facing towards the flame should have a different surface colour- one is matt black and one is silver
3. The ball bearing on the black plate will fall first as black surfaces absorb more infrared radiation and transferring more energy to the thermal energy store of the wax.