Lesson 8: Earth's early atmosphere

Question 1

What is the “atmosphere?”

Answer 1

Atmosphere: layer of gasses that suround the Earth

Question 2

What gas made the vast majority of the Earth’s early atmosphere?

Answer 2

• Carbon dixoide

Question 3

How much carbon dioxide is there in the Earth’s current atmosphere?

Answer 3

0.04%

Question 4

How much oxygen is there in the Earth’s current atmosphere?

Answer 4

21%

Question 5

How much nitrogen is there in the Earth’s current atmosphere?

Answer 5

78%

Question 6

What gases would be released in volcanic activity in the Early earth?

Answer 6

• Carbon dioxide
• Water vapour
• Little amounts of nitrogen

Question 7

How did levels of nitrogen increase?

Answer 7

• Volcanic activity.

- Unreactive gas: began to build up in the air.

Question 8

What happened to the water vapour formed from volcanoes years ago?

Answer 8

• Volacanic activity decreased.
• The Earth’s temperature decreased.
• Water vapour condensed into water that fell as rain.
• The rain soon collected to oceans we see today.

Question 9

What advantage did oceans have?

Answer 9

Oceans decreased levels of carbon dioxide as it absorbed it.

Carbon sink.

Question 10

What process do plants do to absorb carbon dioxide and release oxygen?

Answer 10

Photosynthesis

Question 11

What is the word equation for photosynthesis?

Answer 11

Carbon dioxide + water —–> (presence of light and chlorophyll) Glucose + oxygen

Question 12

What happened to the levels of carbon dioxide and oxygen due to plants?

Answer 12

• Carbon dioxide: decreased as it was absorbed.

- Oxygen: increases as it was released.

Question 13

What is a sedimentary rock?

Answer 13

Sedimentary rock:

- Formed by other rocks/ organisms.

Question 14

What is limestone formed from?

Answer 14

• Limestone is formed from marine organisms.

Question 15

What is coal formed from?

Answer 15

• Coal is formed from plant matter.

Question 16

What are oil/ gas formed from?

Answer 16

• Oil/ Gas formed from marine organisms.

Question 17

Explain the formation of fossil fuels.

Answer 17

Plants absorb carbon dioxide by photosynthesising.
Animals eat the plants.
Plants and animals die.
Compaction, heat, pressure forms fossil fuels (coal, oil, gas.)

Question 18

Explain the formation of chalk/ limestone.

Answer 18

The ocean absorbs carbon dioxide.
Creatures use this carbon dioxide to make their shells.
Creatures die to the bottom of the sea bed.
Shells get crushed by pressure into limestone and chalk.

Question 19

What are fossil fuels?

Answer 19

Fossil fuels are natural, finite materials that are formed from the remains of living organisms.