How to measure pressure
Definitely push with the help of devices Barometer The main barometers, which are named according to the mechanism of experts, are:
U-shaped tube barometer
Ideal gas barometer
The simplest and most famous of these is the U-shaped barometer, in which some mercury is poured into a U-shaped tube and the difference between the ambient pressure (air, which is p0) and the material inside the barometer, which puts pressure on the mercury liquid through the column height difference. Mercury is measured. So this way we can get the real pressure: (P = P0 + ρg (h – h0
In the latter relation P is the pressure and ρ density of matter and P0 is the atmospheric pressure, h0 is the height of the liquid column at atmospheric pressure, g is the acceleration of gravity and h is the height of the liquid column at the pressure of matter.
This Barometer Basically from one Empty air tube It is found that one side is blocked and the other side, which is open, is immersed in a container full of mercury. The pressure of the outside air pushes the mercury from the source into the tube. Mercury rises in the barometer tube to the extent that its weight inside the tube is exactly equal to the force exerted by the air pressure, and then remains in a state of exchange and stillness. As the air pressure changes, the level of mercury inside the tube will also go up and down. Under normal conditions, mercury rises to 29.92 inches or 760 mm in the tube, which is a pressure equivalent to 1013.15 mm. The mercury inside the barometer tube has a convex surface due to its surface tension, which must be read when determining the pressure, the highest convex surface.
Metal Barometer (Aneroid)
Metal barometer It is a mechanical device consisting of a can-shaped cylindrical chamber without air; As the air pressure changes, this chamber contracts or expands. With a relatively complex system consisting of a number of levers and pulleys, these changes are magnified and transmitted to a hand that moves on a graduated plate. A moving indicator that can be fixed at one point is mounted on the barometer to measure pressure changes from the last reading.
A barometer is similar to a metal barometer, except that the effect of pressure changes in an airless chamber is transmitted to a pen, and the pen draws a continuous line on paper wrapped around a rotating cylinder. The vertical axis of this plate is calibrated in units of pressure and the horizontal axis is calibrated in terms of time, which usually has one line every two hours. Precise barographs have also been developed that can measure pressure changes up to one tenth of a millibar. These devices are called microbarographs.