Flashcards in Earths Atmosphere Deck (18):
1
Proportions of different gas in atmosphere
78% Nitrogen
21% Oxygen
Followed by small proportions of CO2 , noble gases and water vapour
2
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
3
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
4
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
5
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
6
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
7
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
8
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
9
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
10
Global climate change - storms
Extreme weather events could become more frequent
11
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
12
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
13
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
14
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
15
What is potable water
Water safe to drink
16
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
17
In places where rainwater is rare but seawater is plentiful potable water can be made from sea water
Using two methods
1)distillation
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
18