8984899
Description
Flashcards by Natalia Cliff, updated more than 1 year ago
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Created by Natalia Cliff
almost 7 years ago
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| Question | Answer |
| What's the structural buildup of the earth? | -crust (thinnest layer) -mantle (biggest layer) -core all of this is surrounded by the atmosphere |
| What are tectonic plates | The earth's crust and upper mantle are cracked into a number of large sections called tectonic plates |
| What causes plates to move? How fast do they move? | Convection currents in the mantle from radioactive processes in the core causes the plates to move at a rate of a few cm a year |
| What happens at plate boundaries? | movements between the plates can be sudden or disastrous causing earthquakes and/or volcanoes |
| What are the proportions of gases in the air? | For the past 200 million, there has been 80% nitrogen, 20% oxygen and some carbon dioxide, water and other noble gases |
| How do scientists believe the atmosphere developed? | -Volcanic activity put CO2 and water vapour in the air -Water vapour condensed into oceans -Plants used CO2 to produce oxygen via. photosynthesis -Oceans stored carbon dioxide (carbon made the shells and bones of marine animals) -Denitrifying bacteria produced nitrogen |
| How long did the early atmosphere exist for? What did it contain? | For one billion years the atmosphere may have contained mainly carbon, little oxygen and some methane and ammonia |
| What is the primodial soup theory? | The idea that there were hydrocarbons and ammonia that were struck by lightning to produce amino acids. This is supported by the Miller-Urey experiment |
| What happened to the carbon of the early atmosphere? | Locked away in sedimentary rocks, carbonates or fossil fuels. Oceans also act as carbon reservoirs, but increased absorption of carbon dioxide affects the marine environment |
| What is air? | A mixture of gases with different boiling points. This means that it can be fractionally distilled to provide a source of raw materials for the industry |
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