1. Topic 6.1 Introduction to the Atmosphere

2. The atmosphere has not always been like this, both abiotic and biotic factors have caused huge fluctuations.
Abiotic factors such as temperature and precipitation.
Biotic factors such as plants and animals.
Clues from:
Sediments
Fossils
Gas trapped in ice
Looking at other planets
Evolution of algae caused an increase in oxygen (there was no free oxygen before this).

7. Albedo effect of clouds
The Albedo effect has to do with the amount of energy that a substance reflects or absorbs.
Linked to how white an object is.
Clouds reflect and absorb a lot of solar energy.
They also trap heat below them depending on how thick and high they are.
You may have noticed that cloudy nights are usually a lot warmer than cloudless ones.