Infrared is a type of energy that is emitted from the surface of all objects and is part of the electromagnetic spectrum. Infrared thermometers work by focusing the light that is coming from a person in the form of infrared rays and tunnelling that light into a special detector - called a thermopile. This thermopile turns the infrared radiation into heat, which then gets converted into electricity. This electricity is then measured and displayed on the screen of your thermometer.