The composition of the air . . .
 
The proportions of gases in the air, and how to find the percentage of oxygen.
 
Making oxygen in the lab . . .
 
Using hydrogen peroxide solution to make oxygen in the lab, and testing for oxygen.
 
Burning elements in air or oxygen . . .
 
What happens when you burn a selection of metals and non-metals in the air, and some generalisations you can make about the oxides which are formed.
 
Acid rain . . .
 
The causes and effects of acid rain.
 
Global warming . . .
 
A quick survey of the greenhouse effect and its influence on global warming.
 
Ozone depletion . . .
 
The effects of atmospheric pollution on the ozone layer in the high atmosphere.