demonstrations:exploring_infrared_radiation_with_a_heat_lamp
Exploring Infrared Radiation with a Heat Lamp
Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★☆ Some safety precautions required to perform safely
Categories: Electromagnetic Spectrum and Waves, Heat
Alternative titles: Feeling Invisible Heat
Summary
This demonstration allows students to feel the warming effect of infrared (IR) radiation from a heat lamp. By placing different materials such as glass, plastic, and aluminum foil between the lamp and their hands, students can observe which materials block or transmit IR radiation.
Procedure
- Set up an infrared heat lamp in a safe, stable position.
- Have students hold their hands at a comfortable distance from the lamp to feel the heat.
- Place a sheet of glass between the lamp and their hands, and note whether the warming effect changes.
- Repeat with a sheet of plastic and then with aluminum foil.
- Compare and discuss which materials block or transmit the infrared radiation.
Links
- None available
Variations
- Use different types of plastics (clear vs. opaque) to see how transmission changes.
- Test tinted or coated glass, such as sunglasses lenses or car window glass.
- Place a thermometer behind each material instead of a hand to collect quantitative data.
- Compare IR blocking with visible light transmission (e.g., foil blocks both, glass transmits visible but blocks some IR).
Safety Precautions
- Do not touch the heat lamp, as it becomes very hot.
- Keep flammable materials away from the lamp.
- Limit exposure time to avoid burns or discomfort.
- Use protective stands or holders for materials instead of students holding them close to the lamp.
Questions to Consider
- Why can we feel the heat from the lamp even though we cannot see infrared radiation? (Because IR radiation carries energy that is absorbed by our skin as heat.)
- Which materials blocked the IR radiation most effectively? Why? (Aluminum foil reflects IR completely, while glass and some plastics allow partial transmission.)
- How does this experiment relate to real-world applications such as window coatings or thermal blankets? (These materials are designed to block or reflect infrared radiation to control heat transfer.)
- How does infrared radiation differ from visible light? (It has longer wavelengths, is invisible to the human eye, but is detected as heat.)
