please answer this question as soon as possible
Answers
Explanation:
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa; 1,013.25 mbar), which is equivalent to 760 mm Hg, 29.9212 inches Hg, or 14.696 psi.[1] The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth, that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.
Answer: HERE IS YOUR ANSWER
Explanation:
We feel it! Extend your thumb that is, roughly, a square centimeter. Do you feel one kilo of weight on it? No? How strange because the atmospheric pressure at sea level is about one kilo per square centimeter.
Ah but the air is a fluid and it presses as much from under as from above. To measure the pressure, you need then to … remove the air under your thumb and that is not easy.
Another way to do it is to take a tube, open at one end and closed at the other, and fill it with water. When vacuum forms at the closed end, the pressure of the water equals that of the air. Congratulation, you have just invented the barometer!
The only problem is that, in order to work, your tube will need to be ten meters high and that is not very practical at home. (incidentally, you know now why a succion pump can’t lift water more than ten meters).
A better way is to use the heaviest liquid we know of: mercury! With mercury the tube can be reduced to 760 mm (29.9 inches) and that so much practical at home!
Incidentally, an aircraft altimeter is nothing else than an aneroid barometer (working with a vacuum box and not mercury). But then, to work properly, it needs constant adjustment to that is the local atmospheric pressure at that time of the day, what pilots call, the QNH.