In order to calculate the exact change in nitrogen at sea level and at 18,000 ft, you need to take into account the many variations already mentioned. A good way of trying to understand air pressure is by imagining blankets on your bed: The more air pressure, the more blankets! So, at sea, it would be like having a hundred (or million!) winter blankets on top of you while you were sleeping. However, the higher you go, the fewer blankets there are, so when you reach the edge of space, there is zero air pressure (density). Each blanket is a layer of weight, so the more there are on top of you, the lower you are, whereas the higher you are, the less there is above you! Air pressure also changes over time - generally caused by a change in temperature, so cool air is heavier than warm air, which is why birds use ‘thermals’ (rising funnels of warm air) to fly. There are too many variable to consider in your questions, without knowing location, and temperature, I would not be able to offer an accurate answer.
If you go here:
www.rcn27.dial.pipex.com/cloudsrus/pressure.html,
you will receive more detailed descriptions which will supplement the summary we’ve already dicussed.
The atmosphere is made up of a mixture of gases (78 per cent nitrogen and 21 per cent oxygen), with water vapour and carbon dioxide and argon also making up these components. The way we perceive gas has to do with certain properties of the gas, as evidenced by a change in the air pressure at sea level and 18,000 ft. It would be hard to ascertain a definite change from sea level to 18,000 ft in nitrogen because such an effect is dependent entirely on its location on earth, the season and even on a day-to-day basis because of temperature fluctuations.
This website www.grc.nasa.gov/WWW/k-12/airplane/airprop.html presents a very accessible way of looking at air pressure at sea level, and gives you the equations for how to calculate viscosity and pressure at sea level. The state of gas changes with altitude, the higher you go, the lower the air density, pressure and temperature become.
If you go here:
www.rcn27.dial.pipex.com/cloudsrus/pressure.html,
you will receive more detailed descriptions which will supplement the summary we’ve already dicussed.
The atmosphere is made up of a mixture of gases (78 per cent nitrogen and 21 per cent oxygen), with water vapour and carbon dioxide and argon also making up these components. The way we perceive gas has to do with certain properties of the gas, as evidenced by a change in the air pressure at sea level and 18,000 ft. It would be hard to ascertain a definite change from sea level to 18,000 ft in nitrogen because such an effect is dependent entirely on its location on earth, the season and even on a day-to-day basis because of temperature fluctuations.
This website www.grc.nasa.gov/WWW/k-12/airplane/airprop.html presents a very accessible way of looking at air pressure at sea level, and gives you the equations for how to calculate viscosity and pressure at sea level. The state of gas changes with altitude, the higher you go, the lower the air density, pressure and temperature become.