A contact thermometer is a temperature measuring instrument that measures temperature by coming into direct contact with an object. These thermometers usually produce a physical or electrical change as the temperature changes, thereby determining the temperature. The most common contact thermometers are mercury or alcohol-filled glass thermometers, thermocouples, resistance thermometers (RTDs), and thermistors. They are widely used in laboratories, medicine, industry, and scientific research.
For example, clinical thermometers are used to measure body temperature in medicine, and thermocouples or RTDs are used to control the temperature of certain equipment in industry. The advantage of a contact thermometer is that it is highly accurate and can be placed in a specific position and measured repeatedly. However, such thermometers require direct contact with the object, which can be limiting in some cases. Nevertheless, contact thermometers are still widely used today due to their ease of use, accuracy, and versatility.