2009 Year 4 Geography – Term 3 Week 1 Assignment
QUESTION: Describe the composition and structure of the atmosphere
The atmosphere consists of various gases, dust particles and pollutants. It also contains water vapour, ozone and carbon dioxide, the water vapour forms clouds and hence precipitation. Clouds help to prevent excessive heating of the earth by reflecting scattering and absorbing incoming solar radiation. They also prevent excessive cooling of the earth by absorbing outgoing terrestrial radiation.