Barometer

A barometer is a device used to measure atmospheric pressure. In typical examples, these instruments use water, air, and mercury to measure atmospheric pressure. A barometer is more commonly used to measure ambient air pressure as Indirect elevation of sea level and climate change is used to predict the weather as well as laboratory environments where general conditions such as temperature and ambient pressure should be under control. We are dealing with relative pressure or gauge pressure, and absolute pressure is actually the sum of the pressure that the gauge pressure indicates, plus the atmospheric pressure, which we call the absolute pressure. They show us the real pressure.
Considering that the atmospheric pressure at sea level is equal to one atmosphere and we want to use water to show this pressure, we need to use a column of water with a height of 10 meters, which is equal to once, and if mercury is used for this purpose. This length will reach about 76 cm of mercury. In practice, many hand-held barometers on the market include a jumper or accordion diaphragm in which a relative vacuum is created and pressure changes cause the bezel to expand and contract, and these changes can be seen by the hand in terms of atmosphere. .