A thermometer that uses mercury as its thermometric liquid is called the mercury thermometer. The following are the advantages of the mercury thermometer:

• It can measure a wide range of temperatures ranging from -39$\rm ^{o}$C to 357$\rm ^{o}$C.
• Mercury expands uniformly over a wide range of temperatures.
• The specific heat capacity of mercury is low.
• Mercury has a distinct colour, i.e., silvery opaque.