Question

State four reasons for using mercury as a thermometric liquid.

Answer 1

Hint: In order to choose any material as thermometric material we need to consider its boiling point and melting point , coefficient of thermal expansion, reaction with different surrounding materials, and its visibility.

Complete answer:
Following are the four reasons for using mercury as a thermometric liquid:-
It has a lower freezing point ($ - 38.83^\circ C/234.32^\circ K/ - 37.89^\circ F$) and a high boiling point ($356.73^\circ C/629.88^\circ K/674.11^\circ F$), which means it can be used over a wide range of temperature.
It has a high coefficient of expansion which makes it easier to move in the thermometers as per the varying temperature, or in other words reacts to the temperature fast enough.
It is a silver coloured opaque metal which does not wet the walls of glass tubes and has a convex meniscus, which eases the visibility .
It is the only metal to be liquid at room temperature($25^\circ C/298^\circ K/77^\circ F$) .
Average human temperature is $98.6^\circ F/37^\circ C$, using a mercury thermometer will be very much suitable for checking body temperatures.

Note:
Mercury thermometers are also used in various industries as well , For e.g. dairies , bakeries , chemical tanks , heating and cooling equipment. Nowadays, Digital thermometers are replacing conventional thermometers as spillage of mercury causes environmental effects and a significant amount is not suitable for humans. Also, Direct contact with liquid mercury can cause irritation and chemical burns and dizziness is one of the immediate effects of it.