Topic 8- Earth and atmospheric science (paper 2)

Question 1

How was Earth’s early atmosphere formed?

Answer 1

By gases from volcanoes

Question 2

What was the composition of Earth’s early atmosphere?

Answer 2

• mostly CO₂
• little to no O₂
• some water vapour
• small amounts of methane and ammonia

Question 3

How were the oceans formed? What did they do?

Answer 3

Cooling of Earth caused the water vapour in Earth’s atmosphere to condense and form the oceans. The oceans also allowed lots of carbon dioxide to dissolve into it from the atmosphere.

Question 4

What two factors caused CO₂ levels in Earth’s early atmosphere to decrease?

Answer 4

• formation of the oceans → absorbtion of CO₂
• early plants that photosynthesized to produce O₂

Question 5

How did the growth of primitive plants cause Earth’s atmosphere to change?

Answer 5

The plants photosynthesised to absorb CO₂ from the atmosphere and produce oxygen

Question 6

What is the test for oxygen?

Answer 6

Oxygen will relight a glowing splint

Question 7

What is the greenhouse effect?

Answer 7

• short wavelength radiation is emmited by the sun
• it passes through Earth’s atmosphere
• the short wavelength radiation is absorbed and them re-emmited as long wavelength, infrared radiation
• this radiation is absorbed by greenhouse gases in the atmosphere (such as methane and carbon dioxide)
• the greenhouse gases then re-rediate it in all directions including back to earth
• the infrared radiation is thermal radiation and so warms the surface of the earth

Question 8

What factors have increased the quantity of greenhouse gases in the atmosphere?

Answer 8

• increasing energy consumption
• deforestation
• methane from cattle farming

Question 9

What do some scientists use as evidence to suupport the idea that global warming is not anthropogenic (caused by humans)

Answer 9

Belief that the current rise in global temperature is just a natural fluctuation and we don’t have enough data to correlate it to human activity

Question 10

What are challenges faced when obtaining climate change data?

Answer 10

• historical recordings of temperature are less accurate (less data and taken all over the world)
• however estimations on past data can be taken from natural materials such as fossils or gas bubbles trapped in ice sheets to estimate past levels of carbondioxide
• these recordings are much less precise than current measurements though

Question 11

What can be done to mitigate the effects of climate change

Answer 11

• cutting down on personal emmisions (e.g. cycling instead of going by car)
• renewable energy sources
• flood defences to stop flooding
• planting trees / having protected areas