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Flashcards in the earth Deck (38):

what is the earths core made from

Nicole and iron


where does the minerals and other resources that we depend on come from

the crust- it's oceans

and the atmosphere


what are tectonic plates

a number of huge pieces the earths crust and upper mantle is cracked into

they are comradely moving slowly


what causes the motion of tectonic plates

radioactive atoms decay releasing heat

makes molten minerals expand, they become less dense and rise

cooler material take their place

forces created by the convection currents makes the tectonic plates move


what happens at the plate boundaries of tectonic plates

huge stresses build up causing mountains and volcanos


what causes earthquakes

if two tectonic plates suddenly slip past eachother


is it easy to predict earthquakes and volcanos

no, cannot measure all the tremmers under the earths crust


how did volcanic activity form the oceans

volcanoes produce water vapour

the water vapour condensed to form oceans


how did volcanoes form the early atmosphere

volcanos release carbon dioxide, water vapour and nitrogen gas - these gases formed the early atmosphere

the early atmosphere would also contian traces of methane and ammonia


why has the amount of carbon dioxide decreased so much since the start and the amount of oxygen increased

plants and algae spread over the earths and seaand replaced some carbon dioxide with oxygen during photosynthesis

oceans formed and absorbed carbon dioxide and it got locked up in sedimentary rocks or fossil fuels


what does the earth consists of

a series of layers

dense solid core
liquid core
thin crust
layer of gas called atmosphere surrounding the earth


what is the Miller Urey experiment

a theory of how the atmosphere developed include the arrival of living things on earth


what does the Miller Urey experiment say

used a mixture of water ammonia methene and hydrogen to model early atmosphere, then the energy required for the gases to react were provided by stimulating lightening

the mixture formed 11 types of amino acids

amino acids make up molecules that make up living things and contain carbon hydrogen nitrogen and oxygen

conclusion: it provided evidence that is was possible to makes the molecules of life from our early atmosphere


what are the problems with other theories about how life started on earth

they are unproven. we can't be sure about the events that resulted in the first life forms on earth


what are the main gases in the earths atmosphere

78% nitrogen
21% oxygen
0.9% Argon
0.04% Carbon Dioxide
trace amounts of others


how can you separate the main gases in the air

fractional distillation

there gases are used in industry as useful raw materials


where has most of the carbon dioxide in the earths atmosphere gone

carbon is taken by plants and animals

they die and build up in oceans

form sedimentary carbonate rocks

form fossils and therefore most of the carbon from the early atmosphere has been locked within the earths crust


what happened to the ammonia and methene from the early atmosphere

amonia and methene reacted with oxygen and the nitrogen levels built up


how do u fractionally distillate air

the air is cooled to -200c

it is then warmed up at the different elements are separated because of their boiling tempreture

nitrogen= -196
argon= -186
oxygen= -183


what has kept carbon levels stable over the past 200+ million years

the natural cycle of carbon

the fact oceans absorb carbon and release it when it's in short supply

the fact plants remove carbon dioxide from the atmosphere

animas add to carbon dioxide via respiration

and when fossil fuels (rocks) are butt it produces carbon dioxide


why has the amount of carbon dioxide in the earths atmosphere rises recently

due to the amount of fossil fuels we now burn


has the atmosphere changed since the earth was formed

yes and still changing

been the same for the last 200million years and provides conditions needed for life

human activities have resulted in further changes in atmosphere


what is the earths diameter



why is the earths core denser than the crust

millions of years ago the heavy materials sank towards the center of the earth while the lighter materials floated on the top


how do we know the structure of the earth if no one has ever seen it

by observing how seismic waves following an earthquake travel scientists have built up out picture of the inside of the earth

also calculated the mass of earth and density, it's a lot denser than the rocks found in the crust. so inside of the earth must be a lot denser than crust


why can't scientist accurate predict when ear quakes and volcanic eruptions will occur

Because they are very complex and difficult to know when the tectonic plates will slip past eachother - so don't know when or where earthquakes will happen


what was wegners evidence of continental drift

1. continents fit like jigsaw
2. Africa and South America have the same patterns of rock layers and same types of plants and animal fossils
3. there couldn't have been a piece of land connecting South America and Africa meaning hey have been joined


why didn't scientists accept wegners ideas

1. no explains toon for how the continents moved

2. he was known as a meteorologist not a geologist therefor less credit for his ideas


when were wegners ideas accepted

1960 when Atlantic ridge was discovered

scientist found out ocean floo was younger than rocks on the continent

youngest rocks formed near magma pushing older rocks away and fitted with the theory of continental drift. it was explained that continental drift is caused by convection currents


how do scientist try to predict volcanos and raw isles

measure angles of volcano (bulges before eruption)

rocks heat us before earthquakes as a result of extreme compression so I rated satiates can monitor earths surface


how was it possible for animals to evolve

plants evolved and successfully colonised the surface of the earth do more oxygen

eventually enough oxygen for animals to use to respire


why don't we know about how life was first formed

all theories are unproven


name another theory of how life on Earth was created based on analysis of meteorites that crash to earth from space

1969 meteor fell and had a range of organic materials found in it called murchison meteorite

70 different amino acids, shows molecules capable of starting life on Earth might have arrived from outer space


how do seas and oceans absorb and release carbon dioxide when nessacawy

as co2 levels I the atmosphere go up so does the co2 levels in sea water.

make insolvable carbonates and are deposited as sediment on ocean floor. insolvable carbonates Produce soluable hydrocarbons tes thT remain dissolved in sea water


what's carbon capture and storage

pumping carbon dioxide in power stations deep underground to be absorbed into porous rocks


give an advantage and disadvantage of carbon capture and storage

adv- reduce co2 emissions

disadv- increase cost of producing electricity by 10%


how did continents form

the earth cooled forming a super continent called Pangaea which formed the separate continents


why did volcanos reduce

because the earth cooled forming a crust