Question

Why is mercury used in thermometers?​

Answer 1

Thermal expansion is the tendency of matter to change in volume in response to a change in temperature, through heat transfer. (1 mark)
Mercury is the only metal that is in liquid state at room
temperature, other metals are solid. It is a good conductor of heat and expands uniformly on heating. (1 mark)
Mercury is used in thermometers because it has a high thermal expansion so that even a small rise in temperature brings about sufficient expansion which can be detected in the capillary of the calibrated part of the thermometer. (1 mark)