Ever changing earth Flashcards
Inner core
-This is the densest part of the Earth
-it is solid because of the very high pressure
-its made out of iron and nickel
Molten iron outer core
-This is a dense liquid
-made of molten iron and nickel
-both of these metals are magnetic
- they make the earth behave like a giant magnet
mantle
-under the crust
-this layer goes down almost halfway to the centre of the earth
-most rock in it is solid , but just under the crust its almost molten
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crust
- it can be as thin as 5km under the oceans
- going up to about 70km under the continents
-its the least dense of earths layers - contains minerals
the atmosphere
- 80% of the air lies within 10km of the surface
what is the upper part of the mantle and crust called
lithosphere
convection currents
these occur in the mantle, acts like a conveyor belt for the plates.
plates move in different directions, this is determined by which way the convection currents are flowing.
hot liquid rock rises while cool liquid rock sinks back down
what are formed by divergent/ constructive plate boundary
new oceanic floor (igneous rock) are formed
transform/ conservative boundary effect
earthquakes
who invented the theory of plate tectonics
Alfred Wegner
what is the earth’s structure made up of
4 layers
- crust
- inner core
- outer core
- mantle
how many tectonic plates are there
7
what was Alfred Wegner
he was a German polar researcher, geophysicist and meteorologist
what was wegner’s earlier theory
that billions of years ago all the continents had been a single super continent called Pangea, his theory suggested that overtime the continents broke up and drifted apart
when was his pieces of evidence to back up his theory accepted
1960 years after he died
what were the pieces of evidence that backed up wegner’s theory
- matching fossils found on different continents separated by vast oceans
- the coastlines of some continents fit together like jigsaw
- similar rock formations on different continents
why did scientists not believe his theory
because earlier he couldnt explain how they moved
conservative boundary
plates move in opposite directions (side by side). they overcome friction and move suddenly. this is an earthquake
destructive boundary
plates move towards eachother. the denser plate sinks and melts. the less dense plates rises, forming mountaions
constructive boundary
as two plates move apart, magma rises into the gap. then the magma cool and solidifies to form new igneous rocks
tectonic plates
these plates are constantly moving due to convection currents in the mantle
1st step of the atmosphere
the earth was formed and had an atmosphere of hydrogen and helium gases
2nd step of the atmosphere
erupting volcanoes releases new gases into the air. the main gases were steam and carbon dioxide with some methane and ammonia being releases
3rd step of atmosphere
as the earth cooled down, the steam condensed and fell as rain. this is how the oceans were formed
4th step of the atmosphere
plant life developed in the oceans. they used up CO2 gas and released O2. most of CO2 was absorbed in limestone rock
5th step of atmosphere
some of the oxygen released by plants turned into ozone. Ozone stops harmful rays from the sun reaching the surface making it possible to live on land
6th step of atmosphere
some of the oxygen reacted with ammonia, giving off nitrogen. more nitrogen was also formed by bacteria living in the soil
7th step of the atmosphere
animal life develops as it is protected from the sun is ozone and can use the oxygen for respiration
8th step of the atmosphere
eventually about 200 million years ago the atmosphere reached the mixture we have today of roughly 21% oxygen and 78% nitrogen
which volcanic gases made up the earths early atmosphere
methane, carbon dioxide, ammonia and steam
whats happened over the years in the atmosphere
- the water vapour condensed and fell as rain
- the carbon dioxide has been absorbed into rock meaning over the years its decreased
how do you test for Carbon Dioxide
you put acid on to calcium carbonate and put the rubber cap on, then you put the tube into the lime water producing bubbles
what do you see when carbon dioxide is blown through lime water
limewater turns milky
how do you test for oxygen
you lit a splint and took of the rubber cap of, ou then blow out the fire so it glows orange and then you place the splint in the oxygen gas
what do you see when you test for oxygen
it caught fire and made a pop sound
whats the percentage of carbon dioxide in the atmosphere
0.04%
whats the percentage of oxygen in the atmosphere
21%
whats the percentage of nitrogen in the atmosphere
78%
whats the percentage of argon in the atmosphere
0.9%
photosynthesis in the atmosphere
carbon dioxide is removed through the air by photosynthesis
respiration in the atmosphere
carbon dioxide is returned into the air through respiration by all living things and produces oxygen which is used by all living things
combustion in the atmosphere
carbon dioxide is returned into he air through the combustion of fossil fuels
environmental effects of the emission of carbon dioxide and sulphur dioxide in the atmosphere
- acid rain
-global warming
-increased levels of carbon dioxide
acid rain
sulphur dioxide dissolves in the water vapour in the atmosphere and condense into clouds which then produce acid rain
negatives about acid rain
- can kill wildlife
- conifer trees affected
- can cause damage to limestone buildings
consequences of global warming
- can cause change in weather patterns
-quicker melting ice caps
-rising sea levels
global warming
the warming of the earth that can be made worse when there are extra gases like carbn dioxide
how can we reduce global warming
by using a method called carbon capture
what is carbon capture
this is storing the carbon dioxide produced under the sea or underground
combustion of fossil fuels
