Atmosphere Flashcards
Atmosphere of earth today
78% nitrogen
21% oxygen
1% other gases
What makes up the 1% of other gases in the atmosphere?
Water vapour
Carbon dioxide
Noble gases
How long has the atmosphere of today been around?
Around 200 million years
What happened during the first billion years on earth?
Intense volcanic eruptions
That released the gases that form the atmosphere
What gases were released by volcanoes in the first years of the atmosphere?
Water vapour
Carbon dioxide
Nitrogen
Small amounts of Methane and Ammonia
What happened as the earth cooled?
The water vapour released by the volcanoes condensed (became liquid)
And formed oceans
what was the early stage of earths atmosphere like?
Mainly Carbon dioxide
Small amounts of nitrogen
No oxygen
Early atmosphere vs today
Early atmosphere = large amounts of CO2
Todays atmosphere = small amount
Early atmosphere = very little/no oxygen
Today = 21% is oxygen
How did the level of CO2 in the atmosphere change?
CO2 formed seabed
CO2 formed corals and shells for organisms
Plants evolved and so took in CO2
Thus removed CO2 from the atmosphere
How were seabeds formed?
Some CO2 dissolved in oceans form a weak acid
Which reacted with minerals to form PRECIPITATES
Which over time formed sediments of carbon rock on the sea bed
How were corals and limestone formed?
CO2 dissolved in sea
Made corals and shells of organisms such as mussels
When the organisms died they formed rock limestone
How did oxygen enter the atmosphere?
Algae evolved in the oceans that photosynthesised
Plants also evolved photosynthesising more
Fossil fuels
Formed from remains of dead animals and plants over millions of years
Examples of fossil fuels
Coal, oil and gas
What is coal made of?
Formed from ferns and trees
What is crude oil made of?
Formed from plankton
When they die if no oxygen present to break them up
They don’t decompose and are compressed by sediment
High heat and pressure = oil
What is gas made of?
Hydrocarbon methane
Formed near oil because it’s formed in a similar way
Summary of how carbon dioxide left the atmosphere
Dissolved in water to form sea beds and organism shells
After plants evolved:
Got taken in by algae and plants during photosynthesis
Trapped as fossil fuels when these carbon based organisms died but didn’t decompose
Summary of how oxygen entered the atmosphere
Algae evolved and photosynthesised oxygen which eventually evolved other plants which did the same thing
How is coal formed?
If the ferns and trees die in marshy wetlands they don’t decompose
Because there is no oxygen for the decomposers (bacteria) to respire
Or too acidic
So they are covered in sediment then compressed due to high temp and pressure
How is crude oil formed?
When plankton dies they settle on mud on sea bed
No oxygen = no decomposition
So they are compressed by sediment
Causing a high temperature and pressure to convert to crude oil
How is natural gas formed?
Same way as crude oil
By compressing non decomposed plankton
What do fossil fuels contain?
Trapped carbon taken in as carbon dioxide during photosynthesis
By the plankton and ferns it used to be
How much carbon dioxide does the atmosphere today contain?
0.04%
Greenhouse gas examples
Water vapour
Carbon dioxide
Methane
What is the greenhouse effect?
The process that keeps the temperature on Earth warm enough to sustain life
Caused by greenhouse gases
However due to human intervention it can have bad consequences
Summary of the greenhouse effect
Short wavelength radiation leaves the sun like ultraviolet light
Some reflected back into space by the atmosphere
Some penetrates through the atmosphere and absorbed by Earth surface
Earth RADIATES long wavelength radiation (infrared)
This energy from the wave is absorbed by greenhouse gases in the atmosphere
Causing temperature to rise
Why does some short wavelength radiation get reflected back into space by the atmosphere?
Because the short wavelength radiation doesn’t interact strongly with the gases in the atoms
Why is carbon dioxide levels increasing in the atmosphere?
Burning fossil fuels that contain trapped carbon
Coal for electricity
Petrol and diesel to power cars
Gas for home heating
Should be taken in by plants for photosynthesis but these rainforests are being destroyed by deforestation
Which only releases more co2
Why are levels of methane increasing in the atmosphere?
Released in agriculture:
Growing rice in flooded paddy field
When cattle and cows pass wind
What do levels of water vapour in the at,o sphere depend on?
The temperature and humidity
So how does human intervention speed up climate change?
Burning more fossil fuels/ certain types of increased agriculture
Release more greenhouse gases which absorb more energy from long wavelength radiation
Thus the atmosphere and earth’s surface temperature increase
Effects of global warming
Rising temperatures will:
Melting polar ice sheets and glaciers = rising sea levels = increased flooding of low lying areas
Severe weather changes such as storms
Changes distribution of animals and insects
Change distribution of insect borne diseases (malaria)
Peer review
When evidence and research for ideas is shared between scientists who can criticise and decide whether it’s valid or not
What is a problem with our understanding of climate change?
It’s complex and difficult to model
So information in media might be simplified or biased
Or speculation based on specific parts of evidence
Carbon footprint
Total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
So gives us an idea of how much something contributes to climate change
Ways to reduce burning of fossil fuels that release carbon dioxide
Using home insulation or turning down the heating
Use public transport rather than using cars (less co2 per passenger)
Switch to renewable sources of electricity like wind power rather than fossil fuels
Turn lights off when not needing it/energy saving lightbulbs
Problems of solutions for using less fossil fuels
Expensive and people are reluctant to pay
Inconvenient in some cases eg using personal transport has more freedom
Ways to reduce emissions of methane
People eat less beef/dairy products to reduce demand for cattle agriculture which is the main producer of methane
Trapping methane produced in landfills and burning it for electricity
Why is the solution for people to buy less dairy/beef not a good idea?
People like those and not likely to switch their diets
Why is the solution to trap and burn methane a good idea?
It’s a much more powerful gas than carbon dioxide
Why is the solution to trap and burn methane a bad idea?
It’s expensive
Fuel
Releases energy when they are combusted (burned)
Eg fossil fuels which are all hydrocarbons
When is coal used mainly?
Burn pt to generate electricity in power stations
When are hydrocarbons used?
Present inside petrol and diesel
Burnt for fuel to power cars
What happens when hydrocarbons/fossil fuels are burnt?
Releases carbon and hydrogen
Reacts with oxygen and oxidised
To form water vapour and either carbon dioxide or monoxide
Word equation for complete combustion of methane
Methane + oxygen ——> carbon dioxide + water
What happens if the amount of oxygen in complete combustion is reduced?
Incomplete combustion which releases carbon monoxide
Carbon monoxide symbol
CO
Word equation for incomplete combustion of methane
Methane + oxygen ——> carbon monoxide + water
Problem with carbon monoxide
Toxic gas
No colour or smell
So you have to have carbon monoxide detectors
How is sulfur dioxide produced?
Coal contains sulfur
When burnt sulfur atoms react with oxygen to form sulfur dioxide
How are oxides of nitrogen produced?
Inside engines ie in cars
Where high temperatures cause nitrogen and oxygen from the air to react
Causing a range of different molecules called NOx (oxides of nitrogen)
Oxides of nitrogen equation
N2 + O2 ——> NOx
Problem with sulfur dioxide and oxides of nitrogen
Breathing problems for humans
Dissolve in water = acid rain
Effects of acid rain
Damages trees
Damages buildings made of limestone
What causes particulates pollution?
Particles of carbon as soot
Unburnt hydrocarbons
Effects of particulates
Damage human health: increase risk of heart and lung disease
Reduce amount of light energy that reach the Earth surface as they absorb the energy = global dimming
Global dimming
When particulates in the air absorb light energy from the sun causing the earth to darken
Can also effect rainfall patterns
