What is the greenhouse effect?

The Earth’s surface and atmosphere stay warm when gases in the air trap from _________the sun. Have you ever been inside a _________________, the all-glass buildings where plants are grown? They’re very warm, because the ________________walls allow the sun’s rays in but prevent the heat from getting out.

Think of the ___________as being inside a giant greenhouse. The gases act like a greenhouse’s glass walls -- they keep heat from _______________ into space, and the earth stays warm.

Try this easy _________________: Take two jars and put a teaspoon of water in each . Put a lid on just one jar. Place both jars in a ___________ spot. After a few ____________, check on the jars. You’ll see that the open jar hasn’t changed, but the closed jar will be steamy and hot inside. What ______________? The heat from the sun could not _____________ from the closed jar.