Greenhouses
In the winter we build a greenhouse in the community garden.
How does a greenhouse work? To understand you need to know how the sun heats the earth.
The Sun heats the earth like a microwave
To test this, put a cup of cold water in a microwave and heat it for 1 minute. The water should be hot but the air in the microwave shouldn't be.
Close the microwave and leave the hot water in it for 5 minutes. When you open the oven, the air should be warmer.
The sun heats the earth in the same way.
Using this knowledge along with the knowledge that hot air rises, gardeners can fool nature and grow plants in the winter.
A greenhouse is a house made of glass, clear plastic or thin cloth which lets sunlight in but traps hot air and keeps it from excaping. The sun's energy enters the greenhouse and heats the soil which then heats the air. Because the warm air can't escape, the temperature in the greenhouse is higher than the temperature outside.
We call it a greenhouse because plants can grow there in the winter.