Earth and atmospheric science

Question 1

How was Earth’s early atmosphere formed?

Answer 1

• High volcanic activity released large amounts of gases such as CO2 and water vapour, and small amounts of nitrogen

Question 2

What did the Earth’s early atmosphere contain? (thought to have contained)

Answer 2

• Mainly carbon dioxide
• Water vapour
• Small amounts of other gases
• Little to no oxygen

Question 3

How were the oceans formed?

Answer 3

4 billion years ago, the Earth cooled down, causing water vapour in the atmosphere to condense in to liquid water

Question 4

What caused a decrease in carbon dioxide on Earth?

Answer 4

• When the oceans formed, carbon dioxide dissolved in the oceans, reducing the amount of carbon dioxide in the atmosphere
• Sea creatures used the dissolved carbon dioxide to form shells made of calcium carbonate, which allowed more carbon dioxide to be dissolved into the oceans

Question 5

How did organisms affect the concentration of oxygen in the atmosphere?

Answer 5

• Some organisms use energy from the sun to make food by photosynthesis
• So, they take in carbon dioxide and release oxygen

Question 6

Describe the greenhouse effect

Answer 6

• Energy is transferred to the Earth by waves (infrared + light)
• Some energy is absorbed by the Earth’s surface, warming it up
• The warm Earth emits infrared waves
• Some gases in the air absorb the energy transferred by the infrared waves
• When they re emit the energy, some of it goes back to the Earth’s surface and warms it