Heat Trapped in the Air

In the picture

1. 1A yellow sun ray passing through the atmosphere: incoming solar energy reaches Earth’s surface.
2. 2A carbon dioxide molecule in the atmosphere: it absorbs and re-emits infrared heat.
3. 3A methane molecule in the atmosphere: it absorbs and re-emits infrared heat.
4. 4A red wavy arrow rising from land: infrared heat leaves the warmed surface.
5. 5A red wavy arrow escaping into space: some infrared heat is not absorbed and leaves the atmosphere.

Examples

• A car parked in the sun gets hotter inside because glass slows heat from escaping.
• A greenhouse stays warm because glass lets sunlight in but slows heat from leaving.

Quiz: Heat Trapped in the Air (Age 18)

1. 1

   What do carbon dioxide and methane molecules do to infrared heat in the atmosphere?

   • They reflect it as visible sunlight.
   • They convert it into oxygen.
   • They absorb it and re-emit some of it.
2. 2

   What happens when there is more carbon dioxide and methane in the air?

   • Less infrared heat is absorbed by the atmosphere.
   • More infrared heat is returned to Earth’s surface.
   • Earth’s surface reflects more incoming solar energy.
3. 3

   What happens to infrared heat that is not absorbed in the atmosphere?

   • It becomes methane in the air.
   • It escapes into space.
   • It is sent back to the sun.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.