the earth Flashcards
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 mantle 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
12800km
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
