The atmosphere (paper 2)

How did the Earth get here?

Big Bang (13.8 billion years ago)

When was the Earth formed?

4\.6 billion years ago

What was the Big Bang?

* an explosion
* (gases and dust)

What were the gases formed from the Big Bang?

Hydrogen and helium

Describe phase 1 of how the Earth’s atmosphere developed

* earth was covered in volcanoes that released gases

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* The early atmosphere was probably mostly co2

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* Volcanoes released nitrogen, co2 and water vapour

What were the 2 other gases that were given off by volcanoes in small amounts?

* methane
* Ammonia

Describe phase 2 of how the Earth’s atmosphere developed

1. Water vapour condensed to form oceans

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2. Co2 was absorbed by the oceans, went through a series of reactions to form carbonate precipitates that formed sediment on the seabed

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3. Green plants and algae evolved, they absorbed co2 and carried out photosynthesis

Describe phase 3 of how the Earth’s atmosphere developed

* more and more co2 taken out of atmosphere
* Forming rocks and crude oil

What is todays atmosphere mostly made up of?

Nitrogen and oxygen

How has carbon locked into rocks?

1. co2 was taken in by plants and converted into glucose and oxygen via photosynthesis

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2. animals eat the plant carbon can be transferred to animals skeletons and shells

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3. skeletons and shells get covered by sediment, forming sedimentary rocks eg. limestone

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4. Remains of ancient animals were crushed by large scale movements of the Earth, and heated by Earth’s crust, forming fossil fuels and natural gas

What do greenhouse gases absorb?

Long wavelength radiation

What is the greenhouse effect?

The warming of the earths surface (thermal radiation)

Stages of the greenhouse effect?

1. Sun emits infrared waves which enter the atmosphere

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2. Radiation is absorbed by the Earth

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3. Longer wavelength radiation is emitted

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4. Carbon dioxide stops further longer wavelength radiation escaping

What human activity affects the amount of greenhouse gases in the atmosphere?

* deforestation - fewer trees = less co2 removed via photosynthesis
* Burning fossil fuels - releases co2
* Agriculture - cows produce methane
* Land fill sites

How does climate change happen?

1. Average temperature of the Earth increases
2. Extra co2 is released due to human activity

What might happen if climate change continues?

* ice caps melting = causing a rise in sea levels = increasing flooding
* Droughts
* Frequency of storms increase

What are carbon footprints?

A measure of how much co2 and other greenhouse gases are released

What are the ways of reducing carbon footprints?

1. __Renewable energy__ sources or nuclear energy rather than fossil fuels

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2. __Tax__ companies based on the amount of greenhouse gases emitted

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3. capturing carbon and storing it underground

What are the disadvantages of reducing carbon footprints?

* governments worries that if they raise tax economic growth might be at risk

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* People’s minds are hard to change and might lack the education to understand

What are the the atmosphere pollutants?

1. Nitrogen oxide
2. Sulfur dioxide
3. Carbon monoxide
4. Carbon dioxide
5. particulates

What’s the difference between complete combustion and incomplete combustion?

When there’s plenty of oxygen so all fuel burns vs when there’s not enough oxygen so some fuels don’t burn

what’s carbon neutral?

products that don’t affect the the atmospheric co2 concentration

what are the problems with carbon monoxide?

* colourless
* odourless

means hard to detect

why does global dimming happen?

participates reflect incoming radiation into space