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.

The following are the disadvantages of the mercury thermometer:

• Mercury is a toxic liquid so it should be handled with care.
• It cannot be used to measure the temperature of very cold regions.