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Flashcards in Earths Atmosphere Deck (18):

Proportions of different gas in atmosphere

78% Nitrogen
21% Oxygen
Followed by small proportions of CO2 , noble gases and water vapour


The Earth’s early atmosphere

Formed 4.6 billion years ago!
For the first billion years, the surface was a very hot turbulent place covered in volcanoes that erupted and released lots of gases (CO2, AMMONIA , WATER) which formed the early atmosphere similar to the atmosphere of Venus and Mars. The water vapour would have condensed to form the oceans and the atmosphere would have been mostly carbon dioxide with virtually no oxygen ! Volcanic activity also released NITROGEN which built up in the atmosphere over time as well as water vapour and small amounts of METHANE and AMMONIA


How carbon dioxide decreased ?

Carbon dioxide decreased as a lot was dissolved in the oceans . This dissolved carbon dioxide and then went through a serious of reactions to form CARBON PREICIPITANTS that formed sediments on the sea bed like limestone reducing the carbon dioxide in the atmosphere


How oxygen increased?

Algae and plants produced oxygen by photosynthesis. As oxygen levels built up in the atmosphere over time , more complex life (like animals) could evolve.

Carbon dioxide + water = glucose + oxygen


Describe how sedimentary rocks are formed

Sedimentary rocks are formed when organic matter such as plant deposits or the shells and skeletons dead of marine animals fall to the sea bed . These become buried and compressed by sediments over millions of years forming rocks


Greenhouse effect

The sun gives out energy in the form of electromagnetic radiation in ultraviolet ( shorter , higher energy) visible and infrared (longer , lower engery) wavelengths . This radiation reaches the Earth and hearts up the surface providing warmth . The earth also gives out energy (in order to cool down) , but it is not as hot as the Sun so gives out radiation only in the form on the longer , lower energy infrared radiation . Unfortunately CO2 CH4 H2P tend to absorb radiation of the infrared wavelets and so this radiation does not fully escape , is retained by the atmosphere and causes global warming


Human activities why carbon dioxide levels are increasing (CO2)

Burning fossil fuels. As the global population increases, so does its demand for energy e.g driving more cars increases burning of petrol

Deforestation. Fewer trees means less photosynthesis meaning less CO2 removed from the atmosphere


Human activities leading in increased methane levels (CH4)

Increased farming (agriculture) farm animals produce methane and so does their manure when it decomposes.

Landfill sites. When waste buried in landfill decomposes , that’s also produces methane


Global climate change - rise in sea level

As the Earth becomes warmer , glaciers and ice caps will melt , causing an increased volume of water in the oceans. In addition as water warms it expands also increasing its volume which could cause floods


Global climate change - storms

Extreme weather events could become more frequent


Global climate change - changes in temperature and the rainfall patterns

This could affect food production by upsetting the growth of crops many which are dependent upon good levels of sunshine and reliable rainfall . Dry areas could become drier and in other parts of the world such as Asia the monsoon rains will become more severe


Global climate change - Wildlife

As the seasons become less predictable , plants and animals whose cycles of flowering / hibernation / reproduction rely Upon seasonal factors such as temperatures and moisture levels may become disrupted along with their habitats. For example, animals may come out of hibernation earlier and find that their normal prey animal or plant has not yet appeared for the spring. Also temperatures rise, polar bears will have fewer ice caps to rest on and hunt


Carbon footprint

The amount of carbon dioxide and other greenhouse gases given out over the full life-cycle of a product or service or an event


How to reduce our carbon footprint

Renewable energy sources or nuclear energy instead of fossil fuels

Increased the efficiency of our use of energy by using more efficient engines in cars, increasing insulation tion in homes, use low energy light bulbs and switching off electrical equipment instead of leaving them on stand by

Lots of waste decomposes to reduce methane


What is potable water

Water safe to drink


How is water collected in lakes and reservoirs made safe to drink?

1)Passed through a sand/gravel filter bed to remove any solid particles eg twigs

2) chlorine gas is added to kill harmful micro organisms.Chlorine has the added bonus that it is relatively safe. The amounts of chlorine are important ! Too little and diseases may occur! Too much is toxic to humans

Ozone and ultraviolet light can ask I’ve used to sterilise water


In places where rainwater is rare but seawater is plentiful potable water can be made from sea water

Using two methods
2)reverse osmosis

Distillation - sea water is heated until it boils . The water molecules turn to steam leaving behind the salt particles . The water vapour is then cooled and condensed

Reverse osmosis- sea water is passed through a semipermeable membrane (filter with very tiny holes) under pressure . The water molecules pass through but many of the dissolved substances do not

Both methods require a lot of ENERGY


Waste water treatment

1) before being treated the water a screened - this removes any large bits of material like twigs or plastic bags)

2)the comminutor grinds up any solids that make it through the screens

3) grit chamber removes grit by gravity

4) the primary sedimation tank (primary clarifier) removes organic waste which sinks to the bottom as sludge

5) the aeration tank is where air bubbles are added and good bacteria kill harmful bacteria

6) the final sedimation tank (secondary clarifier) removes the good bacteria which drip to the bottom as sludge

7) all sludge is collected and treated with bacteria anaerobically to produce methane a biogas which can be combusted to provide energy