What instrument is used to measure temperature?

The instrument that measures temperature is the thermometer. This device functions by utilizing various principles, such as the expansion of fluids or changes in electrical resistance, to accurately gauge temperature in various environments. Common types of thermometers include liquid-in-glass thermometers that use mercury or colored alcohol, digital thermometers that provide electronic readings, and bimetallic thermometers that respond to temperature changes with mechanical movement.

In contrast, the barometer measures atmospheric pressure, which is crucial for weather forecasting and understanding atmospheric conditions but does not provide temperature data. The anemometer is designed to measure wind speed, making it valuable for assessing weather parameters related to airflow, while the hydrometer is used for measuring the specific gravity of liquids, often in the context of determining concentrations of solutions. Each of these instruments serves a specific purpose, highlighting the distinct roles they play in understanding weather and environmental conditions.