Q1.
During the COVID-19 pandemic, some special thermometers were used, which could measure the temperature of a person from a distance. What were those?
Answer
They were non-contact thermometers, also called infrared thermometers.
- They measure a person’s temperature without touching the body — you may have seen one held near the forehead or the wrist at a school gate, a railway station or a hospital.
- Because there is no touching, the same instrument can be used on hundreds of people one after another and it reduces the risk of spreading disease.
- They give the reading in a second or two on a digital display, usually in °C (some can be switched to °F).
Why it works: every warm body gives out invisible infrared radiation. The hotter the body, the more it gives out. A sensor inside the instrument catches this radiation and the electronics convert it into a temperature reading.
Did you know? A digital contact thermometer works differently — it has a heat sensor at its tip that must actually touch the body, which is why it takes longer and must be washed before and after each use.