Which layer holds almost all weather?

• The troposphere, heated from below by the ground
• The stratosphere, heated by ozone
• The thermosphere, heated by thin gas

Air thins smoothly with height. What does temperature do instead?

• Pressure, which rises smoothly
• Air thickness, which zigzags wildly
• Temperature, which falls then rises in turns

Each temperature reversal marks a boundary between layers.

What happens to a rising air parcel inside the stratosphere?

• It sinks back down, since it is cooler than its surroundings
• It keeps rising faster and faster
• It turns into ozone at once

Why does the ozone layer sit where the air warms with height?

• It absorbs visible light at the ground
• It absorbs ultraviolet light and turns it to heat
• It reflects all sunlight back to space

The profile cools, then suddenly warms again higher up. What does that mean?

• The ground stopped warming the air
• Gravity switched off for a while
• A different gas soaks up energy at that new height

What heats each layer of the atmosphere?

• Warm ground below and absorbing gases at fixed heights above
• One heater switched on for the whole sky
• Friction from aeroplanes at each level

Suppose the stratosphere warmed less strongly with height. What follows for weather?

• Storms would spread through all layers evenly
• Weather would stay trapped even more firmly
• Weather could punch higher