At this point they might identify visible light as being solely responsible for the heating effect. When the petri dish with water is placed between the thermometer and the lamp, the temperature will drop. A significant amount of infrared radiation, however, is absorbed by water. We cannot see infrared radiation, but we can perceive it as a sensation of warmth on our skin.
Some animals are highly sensitive to infrared radiation.
The temperature on the thermometer in the wrapped test tube should be lower. Students should recall from the first experiment that water absorbs infrared radiation. Aluminum foil, however, reflects infrared radiation. These blankets also reflect infrared radiation, keeping an athlete warm by reflecting back his or her own body heat. This experiment helps to explain why the sky appears blue and the sun looks yellowish orange.