The instrument used to measure temperature is a thermometer. There are different types of thermometers, including:

• Liquid-in-glass thermometer: This is the most common type of thermometer. It consists of a glass bulb containing a special liquid, such as mercury or alcohol, that expands and contracts significantly in response to temperature changes. The stem of the thermometer has a scale marked for measuring the temperature.

• Digital thermometer: This type of thermometer uses electronic sensors to measure temperature and displays the results on a digital screen.

• Infrared thermometer: This type of thermometer measures temperature by detecting infrared radiation emitted by an object. It is useful for measuring the temperature of objects that are out of reach or too hot to touch.

• Thermocouple: This is a type of thermometer that measures temperature by detecting voltage changes in two metal leads of dissimilar metals placed in close proximity to each other.

• Resistance thermometer: This type of thermometer measures temperature by detecting changes in electrical resistance in a metal wire as the temperature changes.

Thermometers can be used to measure the temperature of objects, liquids, and even the human body.