Question

Why is it not advisable to sterilise a clinical thermometer in boiling water at normal pressure?[

Answer 1

It is not advisable to sterilise a clinical thermometer in boiling water at normal pressure because the typical range of the clinical thermometers is $34\degree C-42\degree C$. As far as the water boils at $100 \degree C$ at normal pressure, the internal capillary of the thermometer can be damaged due to the undesired mercury extension.