Eardrum is an 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.
All of the objects around you are radiating infrared energy right now. Human beings' skin can detect objects radiating lots of infrared energy. When you warm yourself by standing close to a fire, the "warmth" is infrared energy that you are absorbing.
The idea behind the temperature sensor in the ear thermometer is to create a device that is sensitive to very subtle changes in infrared emission. One common sensor is the thermopile, which can be accurate to a tenth of a degree. The thermopile sees the eardrum and measures its infrared emissions. The emission is converted into a temperature and displayed on an LCD.
Size: 115mm x 35mm x 40mm
Weight: 57g
Powered by one 3V CR2032 button battery(included)
