Air pressure variation with height

• jranjit
In summary, the conversation discusses the thumb rule that states the pressure exerted by ten metres depth of water is roughly equal to one atmosphere. The question is whether this rule also applies to pneumatic systems, specifically in the context of a 10 m head difference resulting in a 1 bar difference in pressure between the ends. The response explains that 10m of air does not weigh the same as 10m of water, and the difference in pressure between the two is only about 10/10,000 of a bar.

jranjit

Hi,

I understand the thumb rule that " the pressure exerted by ten metres depth of water is approximately equal to one atmosphere". Is it applicable for pneumatic systems too ?? that with 10 m head difference in air pressure lines there would be 1 bar difference in pressure between the ends

Last edited:
10m of water weighs the same as all the air above your head - so 10m of air is unlikely to weigh the same.
If the atmosphere is roughly 10,000m high then 10m head is about 10/10,000 of a bar different - otherwise you would need to decompress when standing up.

,

I can confirm that the thumb rule you mentioned is applicable for pneumatic systems as well. It is known as the hydrostatic equation and it states that for every 10 meters of depth (or height), there is an increase of approximately 1 atmosphere in pressure. This is due to the weight of the air above pushing down on the air below. In pneumatic systems, the same principle applies - a difference of 10 meters in height between two points in an air pressure line will result in a pressure difference of approximately 1 bar. This is an important concept to consider when designing and operating pneumatic systems, as pressure differentials can greatly impact their performance. I hope this helps to answer your question.

What is air pressure variation with height?

Air pressure variation with height refers to the change in atmospheric pressure as altitude increases or decreases. This is due to the weight of the air above exerting a force on the air below.

What causes air pressure to decrease with increasing altitude?

The decrease in air pressure with increasing altitude is primarily caused by the decrease in density of air molecules as altitude increases. This means that there are fewer air molecules exerting a force on a given area, resulting in lower air pressure.

How does air pressure variation affect weather patterns?

Air pressure variation plays a crucial role in determining weather patterns. Differences in air pressure between different areas can cause winds to blow from high pressure to low pressure areas, resulting in changes in temperature and precipitation patterns.

What instruments are used to measure air pressure variation with height?

The most commonly used instrument to measure air pressure variation with height is the barometer. Other instruments, such as radiosondes and weather balloons, can also be used to measure air pressure at different altitudes.

How does air pressure variation with height affect aircrafts?

Air pressure variation with height can have a significant impact on aircrafts. As altitude increases, the air becomes thinner and less dense, making it more difficult for aircrafts to generate lift. This is why planes must be designed to withstand varying air pressures at different altitudes.