demonstrations:black_vs_white_can_heating

Black vs White Can Heating

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Heat, The Atmosphere, Weather and Climate

Alternative titles: Canned Heat

Summary

This experiment demonstrates how color affects heat absorption by comparing the water temperature in a black-painted can and a white-painted can after exposure to sunlight. The black can absorbs more energy, heating the water inside faster than the white can.

Procedure

  1. Paint one empty coffee can flat white (inside and out) and another flat black.
  2. Fill both cans with about two inches of cold water.
  3. Measure and record the initial water temperature in each can.
  4. Place the cans in a sunny location where they will not be disturbed for two hours.
  5. After two hours, measure and compare the water temperatures.
  6. Discuss why the water in the black can is warmer than in the white can.

Black and Silver - Absorbing Infrared Radiation - Physics Videos:


📄 Learning Lesson: Canned Heat - National Oceanic and Atmospheric Administration: https://www.noaa.gov/jetstream/ll-canned-heat

Variations

  • Try other colors (red, blue, silver) to test their effect on heat absorption.
  • Use cans made of different materials (aluminum, tin, or plastic) to see if conductivity changes results.

Safety Precautions

  • Use caution when handling spray paint and work in a well-ventilated area.
  • Do not drink the water used in the experiment.
  • Ensure cans are stable and cannot tip over in the sun.
  • If using indoors with a lamp, avoid touching hot bulbs.

Questions to Consider

  • Why did the water in the black can heat more than the water in the white can? (The black can absorbed more solar radiation, which it then transferred to the water.)
  • How does this experiment relate to albedo on Earth? (Dark surfaces like forests or asphalt absorb more heat, while light surfaces like ice or snow reflect it.)
  • How does this process connect to climate change? (As ice melts, darker land and water surfaces absorb more heat, amplifying global warming.)