What is a thermometer?

A thermometer is a device used to measure temperature or temperature changes. It typically consists of a sensor (such as a bulb or a thermocouple) and a display unit that shows the temperature reading.

What are the different types of thermometers?

Liquid-in-glass thermometers: These use a liquid (usually mercury or alcohol) that expands or contracts with temperature changes. Digital thermometers: These use electronic sensors to measure temperature and display the reading digitally. Infrared thermometers: These measure temperature from a distance by detecting infrared radiation emitted by an object. Thermocouples: These use two different metals to generate a voltage proportional to the temperature difference between the ends.