The instrument used to measure temperature is called a thermometer. Thermometers come in various types, but they all work on the basic principle of thermal expansion or the change in electrical resistance in different materials due to temperature changes.
There are several types of thermometers, including:
- Mercury Thermometers: These use mercury within a glass tube which expands and rises as the temperature increases. However, due to safety concerns over mercury, their use has declined.
- Digital Thermometers: These provide a digital reading of temperature and use electronic sensors to measure changes in temperature. They are commonly used in homes and medical settings.
- Infrared Thermometers: These measure temperature from a distance by detecting the infrared radiation emitted by an object, making them useful for quick readings without contact.
Overall, the choice of thermometer depends on the intended use—ranging from medical diagnoses to weather observations.