C1 The Earth

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  • Created by: Dechante
  • Created on: 03-05-17 16:54
Explain what plate tectonics is
Section of Earth's crust that floats on the mantle and slowly moves across the surface.
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State why it is difficult to study the structure of the Earth
It is difficult to study the structure of the Earth because the crust is too thick to drill all the way through and scientists will need to study seismic waves made by earthquakes or man-made explosions.
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What is continental drift
Continental drift is a theory put together by Alfred Wegener which suggests that all the continents were once once joined together in a supercontinent called Pangea.
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Explain continental drift
The tectonic plates float on the liquid rock of the mantle. Heat from radioactive processes within the Earth drives convection currents in the mantle. These currents carry the floating plates, and the continents very slowly (only a few cm per year).
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What is the evidence for continental drift?
Scientists found that the sea floor is spreading apart in some places, where molten rock is spewing out between two continents. This lead to the theory of tectonic plates. There is also the same rocks and fossils found relatively to the continents.
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Describe what an Earthquake is
Shaking and vibration at the surface of the Earth resulting from underground movement or from volcanic activity.
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What causes an Earthquake?
Where the boundaries of the plates meet, huge stresses build up. These forces make the plates buckle and deform, and mountains may be formed. The plates may also suddenly slip past each other. These sudden movements cause earthquakes.
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Describe what a Volcano is
A landform (often a mountain) where molten rock erupts onto the surface of the planet.
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Why are volcanoes located where they are?
Where tectonic plates meet, the Earth’s crust becomes unstable as the plates slide past each other, push against each other, or ride under or over one another. Earthquakes and volcanic eruptions happen at the boundaries between plates.
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Discuss why people choose to live by volcanoes despite the risk
The soil around volcanoes is fertile because it's full of minerals from volcanic ash and lava. This makes it good for growing crops. Volcanoes are also tourist attractions. Volcanoes are a source of geothermal energy (electrici
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Know the composition of gases in the Earth's early atmosphere
It probably consisted mainly of carbon dioxide. There may also have been water vapour together with traces of methane and ammonia. Carbon dioxide has decreased because of photosynthesis taking it in.
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Explain the main steps in the evolution of the atmosphere
As plants spread over the Earth, the levels of oxygen in the atmosphere increased.
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Recognise the Miller-Urey experiment
Miller and Urey devised an experiment to test the theory of how life began. They mixed methane, ammonia and hydrogen in a sterile glass bulb. This stimulated the early atmosphere.
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Explain briefly how the Miller-Urey experiment works
A flask of water= ocean, electric sparks= simulate lightning. After a week they analysed the water. They found different organic compounds- carbon compounds that come from living organisms. These included glycine,several other amino acids and sugars.
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Explain briefly what the 'primordial soup' theory is
The idea that complex chemicals needed for living things to develop could be produced naturally on the early Earth.
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Know the composition of gases in the Earth's atmosphere at present
There is 78% of nitrogen in the air and 21% of oxygen. There is also 0.04% of carbon dioxide and 0.9% of argon. The proportion went down because, as the Earth cooled down, most of the water vapour condensed and formed the oceans.
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Discuss how man has affected the composition of the atmosphere
Burning fossil fuels and deforestation are two example of human effect on the environment
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Understand how air can be fractionally distilled
The liquefied air is passed into the bottom of a fractionating column. Just as in the columns used to separate oil fractions, the column is warmer at the bottom than it is at the top. The liquid nitrogen boils=bottom, Gaseous nitrogen=top
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Why is fractionally distilled air important to the industry?
liquid nitrogen is used to freeze food, food is packaged in gaseous nitrogen to increase its shelf life, oil tankers are flushed with gaseous nitrogen to reduce the chance of explosion, oxygen is used in the manufacture of steel and in medicine
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Other cards in this set

Card 2

Front

It is difficult to study the structure of the Earth because the crust is too thick to drill all the way through and scientists will need to study seismic waves made by earthquakes or man-made explosions.

Back

State why it is difficult to study the structure of the Earth

Card 3

Front

Continental drift is a theory put together by Alfred Wegener which suggests that all the continents were once once joined together in a supercontinent called Pangea.

Back

Preview of the back of card 3

Card 4

Front

The tectonic plates float on the liquid rock of the mantle. Heat from radioactive processes within the Earth drives convection currents in the mantle. These currents carry the floating plates, and the continents very slowly (only a few cm per year).

Back

Preview of the back of card 4

Card 5

Front

Scientists found that the sea floor is spreading apart in some places, where molten rock is spewing out between two continents. This lead to the theory of tectonic plates. There is also the same rocks and fossils found relatively to the continents.

Back

Preview of the back of card 5
View more cards

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