Core5 mapped NDA questions
Build the idea
Build exam-ready understanding by connecting the core idea, formulas or facts, worked example and previous NDA questions. Focus on why each rule works, then test it under timed conditions.
Concept
The atmosphere is the envelope of gases around the Earth, divided into layers. Atmospheric pressure is the weight of air per unit area; differences in pressure drive winds.
Pressure decreases with altitude.
Key Points & Formulas
- Layers (bottom-up): troposphere, stratosphere, mesosphere, thermosphere.
- Weather occurs in the troposphere; the ozone layer is in the stratosphere.
- Atmospheric pressure decreases with height.
- Winds blow from high-pressure to low-pressure areas.
Worked Example
Q. In which atmospheric layer do almost all weather phenomena occur?
Weather (clouds, rain, storms) needs water vapour and convection.
These are concentrated in the lowest layer.
So weather occurs in the troposphere.