How is marcury used in tharmometer?

Mercury is used in thermometers because it has a high coefficient of expansion, meaning it expands and contracts at a consistent rate with changes in temperature. This allows the mercury to accurately measure and display the temperature on the thermometer scale. When the temperature rises, the mercury expands and rises up the narrow tube of the thermometer, and when the temperature drops, the mercury contracts and lowers in the tube. This movement of the mercury is then used to indicate the temperature on the scale of the thermometer.