what tool is used to measure pressure
Measuring Atmospheric Pressure. Let's look at how atmospheric pressure is measured. For a long time, atmospheric pressure has been measured by a mercury barometer. The first was invented in 1643 by one of Galileo's assistants. A mercurial barometer has a section of mercury exposed to the atmosphere. The atmosphere pushes downward on the mercury (see image). If there is an increase in pressure, it forces the mercury to rise inside the glass tube and a higher measurement is shown.