Two kinds of greenhouse

The idea

A plant greenhouse keeps warm differently from a planet: it traps warmed air simply because it is a closed space, usually glass-walled, whereas atmospheric gases trap heat by absorbing radiation.

A greenhouse for plants

A glass house for growing plants stays warm in a cool climate.

Does it keep warm in the same way as Earth's atmosphere?

• No, it works differently
• Yes, exactly the same way
• It does not keep warm

Planet or plant greenhouse

Tap the bin where each belongs.

Different methods

On Venus or Earth, gases in the atmosphere trap heat by absorbing the radiation given off by the planet. A plant greenhouse traps warmed air simply because it is a closed space. Both keep things warm, but they do it differently.

Planet: atmospheric gases trap heat by absorbing radiation. Plant greenhouse: warmed air is trapped because it is a closed space, usually with glass walls.

Notes

Planets: gases absorb radiation. Plant greenhouse: closed space keeps warmed air in.

Check yourself

A plant greenhouse keeps warm because it is …

On Earth, heat is trapped by …

Do a plant greenhouse and a planet trap heat in the same way?

In a plant greenhouse, the warmed air …

• full of carbon dioxide. It works by being a closed space.
• close to the Sun. It works by being a closed space.
• a closed space, usually with glass walls — correct. Yes!
• gases that absorb radiation — correct. Yes!
• glass walls. Glass walls belong to a plant greenhouse.
• a closed roof. A closed roof belongs to a plant greenhouse.
• Yes, in exactly the same way. They keep things warm, but differently.
• No, they do it differently — correct. Yes!
• Neither traps heat. Both keep things warm.
• is absorbed by gases. That is how a planet traps heat.
• goes up to the Sun. The air stays in the closed space.
• stays in because it cannot easily escape — correct. Yes!