NBC Select independently determines what we cover and recommend. When you click on or buy through our links, we earn a commission. Learn more. If you or someone in your home is feeling sick, one of ...

A thermometer is made of a vacuum – sealed glass tube with the liquid inside being either mercury, alcohol or a hydrocarbon fluid. The liquid in the glass expands and contracts when the air inside is ...

If you or someone in your home is feeling sick, one of the most important things to do first is to check your temperature with a thermometer. Temperature is an important vital sign that health care ...