34.6 The Atmosphere

34.6.2 State the percentage of the two main gases in the atmosphere.

The 2 main gasses:

Nitrogen                    - 78%

Oxygen                      - 21%

34.6.4 Describe the variation of pressure as altitude increases.

As we climb into the atmosphere, the pressure around us reduces.  

At 18,000 feet, the atmosphere has approximately half the weight as at the surface.

34.6.6 Explain how the partial pressure of oxygen changes as altitude increases.

As we climb into the atmosphere, the pressure around us reduces. 

For example, at 18’000 ft, the atmosphere has approximately half the weight as at the surface.