| G2-1 | Thermopile and heat source. |
| Purpose: | To detect infrared radiation. |
| Description: | The thermopile is connected to a sensitive galvanometer. When the thermopile is pointed at a heat source, there will be a deflection of the galvenometer in one direction with the magnitude dependent on the temperature difference between the heat source and the room. When the thermopile is pointed at a cold source, there will be a deflection of the galvanometer in the opposite direction with the magnitude dependent on the temperature difference between the cold source and the room. |
| References: | Hf-1. |
| Equipment: | Thermopile, galvanometer and heat source such as heater and cold source such as a piece of metal cooled by liquid nitrogen. |