Question:How do thermal cameras work?
The semiconductor chip in digital cameras can detect infrared radiation and record and image.
Everything emits infrared radiation all of the time. The hotter an object is the more infrared radiation it emits.
A thermal camera detects the heat (the infrared radiation) that is emitted by an object and makes a picture called a thermogram using false colours to represent temperatures.
Extra information - not needed for exam
A normal web camera actually contains a special filter to block out infrared radiation. there is often more infrared than light in a room and the camera sees both.
Without the filter the picture would be saturated and appear completely white due to detecting all the infrared.