A changing atmosphere

Question 1

Which gas is there the largest amount of in our atmosphere?

Answer 1

Nitrogen

Question 2

What percentage of nitrogen is there in our atmosphere today?

Answer 2

78%

Question 3

What percentage is there of oxygen in our atmosphere today?

Answer 3

21%

Question 4

What percentage of carbon dioxide is there in our atmosphere?

Answer 4

0.04%

Question 5

What percentage of argon is there in our atmosphere?

Answer 5

0.9%

Question 6

What other gases besides carbon dioxide, nitrogen, oxygen and argon are in our atmosphere?

Answer 6

Water vapour

Question 7

Why is water vapour not usually included statistically when talking about what gases are in our atmosphere?

Answer 7

There is not a constant amount, the amount changes depending on the weather.

Question 8

There is a lot of limestone in the Earth’s crust. Explain how the amount of carbon dioxide in the atmosphere has changed since the earth was formed, and how is this linked to the formation of limestone.

Answer 8

The atmosphere was almost all carbon dioxide when the earth was formed, and it has decreased to approximately 0.04%. Some carbon dioxide in the atmosphere dissolved in the oceans. Some marine organisms use dissolved carbon dioxide to make calcium carbonate for their shells, When they dies, these marine organisms sink to the sea bed and their shells eventually form limestone. The carbon locked up in the limestone originally came from the atmosphere.

Question 9

How can the composition of todays atmosphere be changed by humans? (3)

Answer 9

• By burning fossil fuels
• Farming
• Deforestation

Question 10

How does burning fossil fuels change the composition of todays atmosphere?

Answer 10

It releases carbon dioxide into the atmosphere.

Question 11

Besides carbon dioxide what other gas is released into the atmosphere when coal is burnt?

Answer 11

Sulphur dioxide

Question 12

How does farming change the composition of the atmosphere?

Answer 12

Cattle and rice fields release methane into the atmosphere.

Question 13

How does deforestation change the composition of the atmosphere?

Answer 13

Adds carbon dioxide to the atmosphere if trees are burnt. There are also fewer trees to remove carbon dioxide form the atmosphere.

Question 14

How can the composition of todays atmosphere be changed naturally?

Answer 14

Volcanoes emit sulphur dioxide and carbon dioxide in the atmosphere when they erupt.