Earth and Atmospheric Science

Question 1

Main gases produced by volcanoes when the Earth first formed 4.5 million years ago

Answer 1

Carbon dioxide, steam, ammonia, methane, water vapour

Question 2

How are oceans formed?

Answer 2

Water vapour condensed to form the oceans

Question 3

How did the levels of carbon dioxide first decrease?

Answer 3

By dissolving in the oceans - later, taken in by photosynthetic algae and plants

Question 4

How did the oxygen levels begin to increase?

Answer 4

Pants photosynthesising

Question 5

Where did carbon dioxide eventually became locked up?

Answer 5

In fossil fuels (coal, crude oil and natural gas) and in limestone rocks

Question 6

Why is the ozone layer so important to Earth today?

Answer 6

Ozone blocks harmful rays from the Sun

Question 7

Test for oxygen gas

Answer 7

Relights a glowing splint

Question 8

Test for hydrogen gas

Answer 8

Squeaky pop test

Question 9

How does CO₂, methane and water vapour’s presence in the upper atmosphere lead to global warming?

Answer 9

The Sun gives out U.V. radiation which passes through the atmosphere where it is absorbed by Earth. The Earth re-radiates some of the radiation and I.R. radiation, some of which is absorbed by greenhouse gases. These greenhouse gases re-emit some I.R. radiation back to Earth. Since I.R. is heat, it warms up our atmosphere

Question 10

What human and natural activities lead to an increase in these greenhouse gases?

Answer 10

• Cows produce a lot of methane gas as part of their digestive process
• Burning fossil fuels for energy released CO₂ that has been locked away for millions of years
• Deforestation to provide land for farming reduces the CO₂ removed from the atmosphere by photosynthesis
• Volcanic eruptions release large amounts of CO₂