What is the name of the instrument used to measure temperature?

The instrument used to measure temperature is called a thermometer. Thermometers operate based on principles such as the expansion of liquids or changes in resistance (in digital thermometers) in response to temperature fluctuations. The most common type is the mercury or alcohol thermometer, which expands and contracts in a calibrated glass tube to show the temperature.

While other instruments measure different environmental parameters, they do not measure temperature. A barometer measures atmospheric pressure, a hygrometer assesses humidity levels in the air, and an anemometer gauges wind speed. Understanding these distinctions helps recognize the specific functions of various meteorological instruments.