14.4 The Atmosphere

14.4.2 Name the principal gases which constitute the atmosphere.

The atmosphere is made up of 3 main gasses:

Nitrogen                    - 78%

Oxygen                      - 21%

Trace Gases              - 1%

14.4.4 Define air density.

Density is the number of molecules in a given volume of air.

14.4.6 Explain how air density varies with altitude within the atmosphere.

14.4.8 State the relationship between pressure/temperature and the density of an air mass.