What type of thermometer utilizes the expansion of mercury to measure temperature?

The thermometer that utilizes the expansion of mercury to measure temperature is the mercury thermometer. This type of thermometer operates based on the principle that mercury expands and contracts uniformly with changes in temperature. When the temperature increases, the mercury expands and rises in the narrow tube of the thermometer, while a decrease in temperature causes the mercury to contract and fall back down.

This straightforward mechanism allows for accurate readings of temperature, particularly within a specific range where mercury remains in a liquid state. In addition to being a reliable method for measurement, the clear scale on the thermometer enables easy reading of the temperature.

Other options like digital and electronic thermometers typically rely on electronic sensors and digital displays rather than the physical properties of a liquid to measure temperature. A tympanic thermometer uses infrared technology to measure the temperature inside the ear, making it notably different in operation from a mercury thermometer.