Description: A thermometer is an instrument that measures temperature. There are many different types of thermometers, but they all work on the same basic principle: they measure the amount of heat energy in an object. Thermometers are used in a variety of applications, including medical, scientific, and industrial settings. In medicine, thermometers are used to measure body temperature. In science, thermometers are used to measure the temperature of liquids, gases, and solids. In industry, thermometers are used to monitor the temperature of machines and processes.