4 Mar 10
The greenhouse effect is caused by an atmostphere containing gases that absorband emit infrared radiation. A greenhouse is built of any material that passes sunlight, ususally glass or plastic. It mainly heats up becuase the sun warms the ground inside, which then warms the air in the greenhouse. The air continues to heat beacuse it is confined with the greenhouse, unlike the envoinment inside the greenhouse, where warm air near the surface rises and mixes with cooler air aloft.