Examples of Atmospheric Pressure

We explain that what are examples of atmospheric pressure? Atmospheric pressure is the  force exerted by gases in the atmosphere on the earth’s surface . Its magnitude will vary depending on the altitude at which the observer is located, for example:

• When we are at the top of a mountain, the column of gases that is going to oppress us will only extend from the top to the atmosphere. It will be a few kilometers. There the atmospheric pressure will be small.
• At sea level, the atmospheric pressure will be the standard one, because the column of gases will comprise, as it is, from the earth’s surface to the atmosphere.
• In the deep parts of a mine or well, the column of gases that will exert the pressure will be longer, so that a higher atmospheric pressure will be felt.

Knowing that gases are made up of fast-moving molecules, you can understand why they act the way they do. If we descend into a mine or travel by plane, our eardrums respond to the change in altitude, adjusting the pressure in our ears and causing the peculiar sensation that they are blocked.

Atmospheric Pressure Equivalences

Atmospheric pressure, being a universally used quantity, has been applied in a wide range of units, both in the international system and in the English system. The standard atmospheric pressure of 1 atmosphere is taken as a reference.

1 atmosphere

= 760 mmHg

= 101325 Pascal

= 1,013 bar

= 1.0336 Kg / cm2

= 14.69 psi or lb / in2

Torricelli Barometer

The standard pressure of the atmosphere was measured for the first time with an instrument called a  barometer , devised by Evangelista Torricelli in 1644. This apparatus was obtained by completely filling a glass tube about 1 meter long, closed at one end, with pure mercury. and submerging the lower open one, in a tank of mercury.

The mercury was filling the glass tube, but in the end it descended somewhat, leaving a partial vacuum (Torricelli vacuum) at the top sealed part of the tube. The  air pressure  on the surface of the mercury in the tank  is  exactly balanced  by the column of mercury contained in the tube.

Looking carefully, it was found that the height of the mercury column was constantly varying, which shows that the air pressure or atmospheric pressure is not always the same; at sea level it can go down to 740mm or up to 780mm.

The pressure that sustains or balances a column of mercury 760 mm high has been adopted as normal pressure to measure the volumes of gases, and is called:  1 atmosphere . In addition, because of the apparatus that determined it, it has been given the name of  barometric pressure .

760mmHg = 1 atm

This measurement is the mean atmospheric pressure at sea level and at 45 degrees latitude, equal to 1.0336 Kg per square centimeter. (1.0336 Kg / cm ² ). At about 4500 meters of altitude the atmospheric pressure is about 400 mmHg, while at about 18 kilometers it is about 40 mmHg.

Aneroid Barograph

The aneroid barograph is an  atmospheric pressure meter  that  includes a graph on paper , on which a pen will trace the variation of atmospheric pressure with respect to time. It is quite useful in laboratories, where the precise value of this pressure is required without having to resort to experimental methods to determine it.

Examples of Atmospheric Pressure

Examples of atmospheric pressure at various points on the planet are listed.

1. The atmospheric pressure in Porto, Portugal, is 100,542 Pascal.
2. The atmospheric pressure in Bern, Switzerland, is 101,800 Pascals.
3. The atmospheric pressure in Tokyo, Japan is 101,896 Pascals.
4. The atmospheric pressure in Buenos Aires, Argentina, is 100,700 Pascals.
5. The atmospheric pressure in Lima, Peru, is 751 mmHg.
6. The atmospheric pressure in Barcelona, ​​Spain, is 101727 Pascal.
7. The atmospheric pressure in London, United Kingdom, is 101829 Pascals.
8. The atmospheric pressure in Toronto, Canada, is 99,390 Pascals.
9. The atmospheric pressure in Mexico City is 77616 Pascal.
10. The atmospheric pressure in Kansas City, USA is 102,700 Pascals.
11. The atmospheric pressure in Belmopan, Belize is 101,600 Pascals.
12. The atmospheric pressure in San Salvador, El Salvador is 94108 Pascals.
13. The atmospheric pressure in Managua, Nicaragua, is 100271 Pascals.
14. The atmospheric pressure in Tegucigalpa, Honduras, is 90044 Pascal.
15. The atmospheric pressure in Panama, Panama, is 101,000 Pascals.
16. The atmospheric pressure in Stockholm, Sweden is 100,200 Pascals.
17. The atmospheric pressure in Berlin, Germany is 102 100 Pascals.
18. The atmospheric pressure in Oslo, Norway is 102,600 Pascals
19. The atmospheric pressure in Helsinki, Finland is 98,600 Pascals.
20. The atmospheric pressure in Ottawa, Canada is 103,100 Pascals.