Topic 1

Question 1

Name the two main gasses that make up the earths atmosphere today

Answer 1

Carbon Dioxide and Oxygen

Question 2

Explain why today’s atmosphere is different than the earths early atmosphere

Answer 2

In the Earths early atmosphere was made up of mostly molten from constant erupting volcanoes. this soon calmed down and the Earth began to cool down which formed the oceans and prevented volcanoes.
After this Green plants began to evolve which produced oxygen. this reduced the amount of C02 which dissolved in the oceans and taken up by the plants which produced 02 by photosynthesis. This caused the oxygen level to gradually increase.
Finally the ozone layer allowed evolution of complex animals. The ozone layer was created by the amount of oxygen, and it blocked harmful rays from the sun and enabled even more complex organisms to evolve, eventually - us.

Question 3

How were the oceans formed?

Answer 3

Volcanoes give out lots of gasses including carbon dioxide, water vapour, and small amounts of other gasses. The oceans formed when the water vapour condensed. This also helped the atmosphere to form.

Question 4

Apart from humans, what else is changing the atmosphere?

Answer 4

Volcanic activity

Question 5

Describe how you can investigate the proportion of oxygen in the air.

Answer 5

Heated copper reacts with oxygen in the air to make copper oxide - so the reaction uses up oxygen.
If you heat an excess of copper in a tube and pass air over it using syringes, you can use the markers on the syringes to tell how much oxygen has been used up.
The chemical exuation for the reaction is 2Cu + O2 -> 2Cuo

Question 6

List three ways in which human activity is changing the earths atmosphere.

Answer 6

Burning fossil fuels
Deforestation
Lifestock farming