How do ear thermometers work?
How do ear thermometers work? It turns out that the eardrum is an extremely accurate point to measure body temperature from because it is recessed inside the head (just like your tongue). The problem with the eardrum is that it is so fragile. You don’t want to be touching the eardrum with a thermometer. This makes the detection of the eardrum’s temperature a remote sensing problem. Granted, it is not very remote — just a centimeter or so. But it’s remote nonetheless! It turns out that the remote sensing of an object’s temperature can be done using its infrared radiation. This technique is a very good way to detect the temperature of a person’s eardrum. All of the objects around you are radiating infrared energy right now. Human beings don’t have any sensors that can detect subtle differences in infrared, but our skin can detect objects radiating lots of infrared energy. When you warm yourself by standi
