 | Term | Definition |
| |
Lithosphere |
Upper Mantle and Earth's Crust |
| |
Tectonic Plate |
Huge sections of the lithosphere that move |
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Atmostphere |
A layer of gasses |
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Atmostphere contains these gases |
Nitrogen 80%, Oxygen 20%, Carbon Dioxide |
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Crust |
Top layer of earth |
| |
Depth of Crust under continents |
35km |
| |
Depth of Crust under oceans |
5km |
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Density of Crust under continents |
Less dense (granite) |
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Density of Crust under oceans |
More dense (basalt) |
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Mantle |
Second layer with two parts |
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Upper Mantle |
Magma |
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Lower Mantle |
Solid rock (more dense) |
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Core |
Centre of eart (2 layers) |
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Outercore |
Made of magnetic materials |
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Innercore |
Densest part of the earth |
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Evidence of structure of earth |
Study of rocks, mines, volcanoes, earthquakes (seismic waves), and magnetic field. |
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Why the earth's core is hot |
Radio active decay of isotopes |
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What did Wegner first notice? |
Continental fit - south america and west africa (coincidence?) |
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What is the mid atlantic ridge? |
Lava was spewing out and cooled |
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Earth's surface slit up into these |
Tectonic plates |
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Why do tectonic plates move? |
Due to convectionn currents in the mantle |
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What may happen where tectonic plates meet? |
Volcanoes and tsunamis form, earthquakes may happen |
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Why are there convection currents in the earth? |
Radioactive decay produces lots of energy |
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When was the earth created? |
4.5 billion years ago |
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What was the scene at the begining of the the earth? |
Volcanoes belching fire and smoke |
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What did the first volcanoes release? |
Carbon dioxidem water vapour and nitrogen gas |
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How were the oceans formed? |
Water vapour condensed and fell as rain |
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How else was water brought to earth? |
Icy comets |
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What was the early atmostphere made from? |
Carbondioxide, some water vapour, nitrogen, traces of methane and ammonia, no oxygen |
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How did we get oxygen on the earth? |
Early life forms could take energy from the sun and produce oxygen (photosynthesis) |
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Atmostphere contains tiny amounts of what? |
Noble Gases |
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Group for Noble Gases |
Group 0 |
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Name the Noble Gases |
Helium, Neon, Argon, Krypton, xenon, Radon |
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What is useful about noble gasses |
Not reactive |
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What do we call molecules that exist as single atoms? |
Monatomic |
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Use of Helium |
Airships and balloons. Low density so floats in air but not flammable. |
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Use of Neon |
When we pass an electricl current through it glows |
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Use of argon |
The inert atmostphere inside a bulb so the filament doesn't burn away |
