This demonstration shows how emissivity affects heat radiation by comparing the cooling rates of hot water in a black can versus a shiny silver can. The black can radiates heat more efficiently and cools faster than the silver can.

1. Boil water in a kettle.
2. Fill both the black can and the silver can with boiling water.
3. Cap each can and insert a thermometer (or thermocouple probe) through the cap.
4. Record the starting temperatures of both cans.
5. Monitor and record the temperatures at regular intervals as the cans cool.
6. Compare cooling rates: the black can should cool more quickly due to higher emissivity.

Black and Silver - Emitting Infrared Radiation - Physics Videos:

📄 Two-can Radiation - buphy.bu.edu: https://buphy.bu.edu/~duffy/thermo/4B40_40.html

• Try cans of other colors (white, red, blue) to compare their emissivity.
• Use painted surfaces versus unpainted metallic surfaces.

• Handle boiling water carefully to prevent burns.
• Use heat-resistant gloves or tongs when pouring water.
• Ensure thermometers or probes are properly secured to avoid spills.

• Why does the black can cool faster than the silver can? (Black surfaces have higher emissivity, so they radiate heat more efficiently.)
• Why does the silver can retain heat longer? (Shiny surfaces reflect radiation and have lower emissivity, so they emit heat more slowly.)
• How does this principle apply to everyday life? (For example, car colors affect heating and cooling, and space blankets use reflective surfaces to retain heat.)
• How does this experiment relate to Earth’s climate system? (Surfaces with different emissivity, such as ice versus land, affect how Earth radiates heat into space.)