Black, white or silver?
Set up time
What you need
Thermometer, aluminium cans, black paint, white paint, silver paint, clock, cardboard, measuring jug, water
To demonstrate how some colours reflect heat, while others absorb heat. As an extension, explore thermal infrared energy, which is outside the normal colour spectrum.
Your students will make predictions before conducting the experiment, based on their knowledge of thermal conduction.
Your students will observe the effect that the three colours have on the temperature of the water.
Your students will use a thermometer to measure temperature, and create graphs to record results.
Take three aluminium cans. Paint one black, one white and one silver. Pour identical amounts of cold water in each.
Measure the starting temperature in each can. Ask students to predict which can will heat the water the most, and the least.
Place the three cans in the full sun, and then measure the temperature in each can every 20 minutes.
At 60 minutes, measure the final water temperature in each can. Discuss the results and record in a graph.
|In this experiment, what variables other than the can’s colour can affect the temperature?|
|What are some areas of your house in which the conduction of heat is good, or bad?|
Extension: Thermal infrared energy
Everything on earth gives off thermal energy. Scientists are using this phenomenon – and the tools to measure the thermal energy in infrared radiation – to track and monitor everything from heat waves to hurricanes.
All forms of matter give off thermal energy. This heat is the primary source of infrared radiation.
Infrared radiation (or light) is a form of light we cannot see. But we can feel it as heat.
Scientists use tools to measure thermal infrared radiation to study things beyond what we can see.
Using various instruments, scientists can predict and track major weather events around the globe.