Infared

• Investigating how much infrared radiation is absorbed or radiated by different surfaces

  1. Observe glowing coals emitting visible light

  2. Understand that hot surfaces emit infrared radiation

  3. Use a Leslie's cube with 4 different surfaces (shiny metallic, white, shiny black, matte black)

  4. Fill Leslie's cube with hot water

  5. Point infrared detector at each surface and record infrared emission

  6. Ensure same distance between Leslie's cube and detector for repeatability

  7. Observe that matte black surface emits most infrared, followed by shiny black, white, and shiny metallic emits least

  8. Use a thermometer with black bulb if no infrared detector available, but less resolution

  9. Use infrared heater with two metal plates (one shiny metallic, one matte black)

  10. Attach pins to plates with Vaseline

  11. Switch on heater and time how long it takes for pins to fall off due to Vaseline melting

  12. Observe that pin falls off matte black plate first, as matte black absorbs more infrared than shiny metallic