How do thermometers and radar and sonar measure?

Answer 1

Sonar ( sound Navigation and Ranging) is a technique that uses sound propagation (usually underwater) to navigate communicate with or detect other vessels (it mainly measures under water distances)

A radar system has a transmitter that emits magnetic waves When they come into contact with an object they are scattered in all directions. The signal is thus partly reflected back and it has a slight change of wavelength , if the target is moving. The receiver is usually in the same location as the transmitter. Although the signal returned is usually very weak, the signal can be amplified through use of electronic techniques in the receiver and in the antenna configuration. This enables a radar to detect objects at ranges where other emissions from the target object, would be too weak to detect .(thus it measures microscopic or even large movements)

3.thermometer simply measures the heat(thermal)i.e,the temperature in Fahrenheit or Celsius subsequently a clinical thermometer measures the temperature of our body