GCSE Physics (AQA)
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The Atmosphere
- The atmosphere is a thin layer of air around the Earth's surface.
- Air is a mix of nitrogen, oxygen, and other gases.
- The atmosphere is the result of gas particles being held close to the Earth's surface by its gravitational field.
- A gravitational field is generated by an object's mass, pulling other mass to the center.
- There is a large concentration of air particles close to the Earth's surface due to gravity.
- Other planets don't have the right conditions to maintain an atmosphere, so air escapes or is absorbed.
- Air particles are less concentrated further from the Earth where the gravitational field is weaker.
- A gravitational field becomes weaker the further we are from the center, resulting in fewer air particles.
- There is less air further from the center as gravity is weaker, making it harder to keep air in the atmosphere.
- It becomes harder to breathe when climbing mountains due to less concentrated air particles.
- Climbers may need an air supply at high altitudes.
- For exams, it's important to explain the Earth's atmosphere and how air molecule density changes with height.
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