University of Virginia
Physics Department

## Introduction to Transfer of Heat by Radiation

A Physical Science Activity

### Student Activity

Materials (for each group of three)

• 2 tin cans, one spray painted matte black and the other spray painted matte white.
• 2 long thermometers
• 4 Styrofoam tops that can press onto the tops of the jars and have a hole in the middle for the thermometers
• 1 jug of water at room temperature (about 24°C)
• 1 stopwatch or timer
• 2 small desk lamps, each with 100 Watt bulbs

Procedure
1. Pour the same amount of water in each of the two cans (about 200 mL), put the lid on, put the thermometer in, and place the cans in front of the lamps as shown. Measure the original temperature and write it on the data sheet. The initial temperatures of the liquids should be the same.

2. Turn on the lamps and start the stopwatch. Read the temperature of the thermometers each minute and write it down on the data sheet. After 20 minutes stop the experiment.
3. On the graph paper, graph the temperatures versus time for both cans. Make sure to remember what container each data point came from!

To print out the Data Sheet only, click here
.

Data Sheet

 White tin can Black tin can Original temperature Temp after 1 minute 2 minutes 3 minutes 4 minutes 5 minutes 6 minutes 7 minutes 8 minutes 9 minutes 10 minutes 11 minutes 12 minutes 13 minutes 14 minutes 15 minutes 16 minutes 17 minutes 18 minutes 19 minutes 20 minutes

Questions

1. Which container experienced the larger temperature increase? Why?

2. Which container had the smaller heat increase? Why?