KAJ Earth's Atmosphere

Question 1

When was the Earth formed?

Answer 1

Earth was formed 4.6 billion years ago

Question 2

How do scientists know what the early atmosphere was like?

Answer 2

scientists have reconstructed what the atmosphere was like based on gas bubbles trapped in ancient rocks/ice and planets and their moons in the solar system

Question 3

How was the early atmosphere formed?

Answer 3

Through volcanic eruptions
- they believe volcanoes released CO2, N2 and H2O(g) (water vapour) forming the early atmosphere

Question 4

How were oceans formed?

Answer 4

All this water vapour cooled and it fell as rain, forming the oceans
OR
Icy comets rain down on Earth, melting and adding to its water stores

Question 5

What was the Earth’s atmosphere like as it began to stabilise?

Answer 5

As Earth began to stabilise it was mainly CO2 - there would have been N2, water vapour and traces CH4 and NH3, but very little O2

Question 6

What did the Earth’s early atmosphere resemble?

Answer 6

Resembles the atmospheres of Mars and Venus - our closest planets

Question 7

When did the first organisms form?

Answer 7

The first organisms formed 3.4 billion years ago

Question 8

What formed after the first organisms and when?

Answer 8

Then, bacteria and other simple organisms like algae formed 2.7 billion years ago
- Algae photosynthesised to release O2

Question 9

What happened in the atmosphere after algae formed?

Answer 9

Over the next billion years O2 steadily rose in the atmosphere and CO2 fell as plants photosynthesised and algae and bacteria thrived in seas

Question 10

What happened to the earth as plants evolved?

Answer 10

As plants evolved, they colonised the Earth surface
As the atmosphere became richer in O2, it became possible for the first animal forms to evolve

Question 11

Why are most early organisms no longer alive as a species?

Answer 11

Most early microorganisms couldn’t survive the increasing o2 concentration but some survived (algea)

Question 12

How did the mixture of gases in the earth’s early atmosphere form?

Answer 12

Some scientists suggest that the mixture of gases would have been formed from solar debris –> similar to comets smashing into Earth and vaporising around 500 million years its formation

Question 13

How are/were fossil fuels formed?

Answer 13

The remains of ancient living things were crushed by large scale movements of the earth and were heated within the crust and formed fossil fuels

Question 14

What type of rock is coal?

Answer 14

coal is sedimentary rock

Question 15

How were crude oil and natural gas formed?

Answer 15

crude oil and natural gas were formed from the remains of plankton deposited in muds on the seabed –> found deposited under layers of rock

Question 16

Why has CO2 levels not changed that much during the last 200 millions years?

Answer 16

due to the carbon cycle

Question 17

How were CO2 and N2 formed in the atmosphere, due to reactions with oxygen?

Answer 17

methane and ammonia found in the early atmosphere reacted with oxygen to make co2 and N2

Question 18

What are the main greenhouse gases?

Answer 18

the main greenhouse gases are co2, ch4 and water vapour

Question 19

What do greenhouse gases do?

Answer 19

greenhouse gases absorb energy radiated from the earth’s surface
- insulate the earth
- leads to global warming due to lots of CO2

Question 20

How much energy reaching earth from the sun is reflected back into space?

Answer 20

30%

Question 21

What wavelength do greenhouse gases let pass through the earth’s atmosphere?

Answer 21

greenhouse gases let short wavelength EM waves pass through

Question 22

Why does global warming occur?

Answer 22

earth cools down by emitting infrared radiation but greenhouse gases absorb it

Question 23

What happens if there is a high proportion of greenhouse gases in the atmosphere?

Answer 23

the higher the proportion of greenhouse gases in the atmosphere, the more energy that is absorbed

Question 24

What has happened over the last century to increase levels of CO2 in the earth’s atmosphere?

Answer 24

over the last century burning fossil fuels to generate electricity has increased co2 levels greatly

Question 25

What are some sources of methane?

Answer 25

sources of methane: decomposing waste of cattle, landfill sites, rice fields, swamps

Question 26

What are Carbon sinks and what do they do?

Answer 26

CO2 sinks = oceans and tropical rainforests –> absorb co2 from the atmosphere

Question 27

How does temperature increases affect levels of CO2 in the atmosphere?

Answer 27

temperatureincreases, co2 becomes less soluble

Question 28

What are some consequences of changing global weather patterns?

Answer 28

• increasingly common extreme weather events
• changes in temperature and amount and timing of rainfall distribution –> affects the capacity to different regions to grow food, plants, etc
• rising sea levels due to melting ice caps and expansion of warmer oceans –> can cause flooding of low lying land, increased coastal erosion, and islands may disappear
• changes to distribution of wildlife species with some becoming extinct - rapid changes will put ecosystems under stress

Question 29

What is a Carbon footprint?

Answer 29

Product, service or event

the total amount of co2 and other greenhouse gases emitted over its full life cycle

Question 30

What is Carbon capture and storage?

Answer 30

pump co2 deep underground to be absorbed into porous rocks - this can be done into old, redundant oil fields
methane produced by cattle can be reduced by reducing the demand for beef

Question 31

What are the ways the government is trying to reduce the carbon emissions?

Answer 31

-taxing fossil fuels
-taxing cars that burn lots of petrol/diesel
-support the use of biofuels
-there are policies that say when trees are felled, new ones must be planted in its place

Question 32

What are issues with trying to reduce carbon footprint?

Answer 32

• cost
• lifestyle changes
• people that disagree that climate change has consequences

Question 33

How is sulfur dioxide formed?

Answer 33

Sulfur impurities in fossil fuels become sulfur dioxide when burned

Question 34

What does sulfur dioxide cause?

Answer 34

SO2 is the cause of acid rain which damages trees and kills animals and plants in lakes
- It also damages buildings made of metals and limestone

Question 35

How is sulfur dioxide removed in coal fired power stations?

Answer 35

In coal fired power stations, sulfur dioxide is removed from the waste gases (flue gases) by reacting it with basic calcium oxide or calcium hydroxide

Question 36

What is produced in incomplete combustion?

Answer 36

In incomplete combustion CO is produced

Question 37

What is carbon monoxide? + effects?

Answer 37

CO is toxic, colourless and odourless
CO is toxic as it takes up the sites on haemoglobin that usually bond to oxygen
Someone who gets CO poisoning becomes O2 starved - drowsy, lose consciousness, and then die

Question 38

What happens in high temperature engines?

Answer 38

High temperatures inside an engine allow the normally unreactive N2 in the air to react with oxygen, making oxides of nitrogen

Question 39

What is the effects of oxides of nitrogen?

Answer 39

Oxides of nitrogen are toxic and trigger people’s asthma

Question 40

How does global dimming occur?

Answer 40

When the large hydrocarbons and diesel engines react with oxygen, they don’t burn completely, and tiny solid particles of carbon and hydrocarbons are produces –> these particulates rise into the atmosphere, reflect sunlight back into space and cause global dimming