Heat Trapped in the Air

In the picture

1. 1Bright Sun: source of incoming sunlight
2. 2Straight yellow arrows: sunlight travelling down to the ground
3. 3Warm curved ground: Earth’s surface heated by sunlight
4. 4Red wavy arrows: infrared radiation rising from the warmed ground
5. 5Three-atom gas molecules: airborne gases that absorb and redirect infrared

Examples

• A car interior stays warm after sunlight passes through the windows.
• A thick blanket holds body heat close on a cold night.

Quiz: Heat Trapped in the Air (Age 17)

1. 1

   After sunlight reaches Earth’s surface, what happens according to the card?

   • The surface reflects all sunlight without warming.
   • The surface warms and then emits infrared radiation.
   • The surface cools by sending visible light into space.
2. 2

   What do the gases in the air do to infrared radiation?

   • They turn infrared radiation into sunlight.
   • They stop sunlight from reaching Earth’s surface.
   • They absorb it and send part of it back toward the ground.
3. 3

   Which sequence best matches the greenhouse effect shown on the card?

   • The surface emits sunlight, gases absorb it, and the Sun warms the ground.
   • Sunlight warms the surface, the surface emits infrared, and gases absorb it and send part back down.
   • Gases emit sunlight, the ground absorbs infrared, and the planet cools.

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.