You will learn about "Greenhouse Effect" in this video. The sun's rays help to warm our planet earth. A part of the sun's radiation that falls on the earth is absorbed and a part of it is reflected back towards the space. A part of this reflected radiation is trapped by the greenhouse gases of the earth's atmosphere. These trapped radiations of the sun help in warming the earth.
The greenhouse gases comprise mainly of carbon di oxide, methane and nitrous oxide. Do you know why these gases are called greenhouse gases? Have you ever seen a greenhouse in a nursery? In a greenhouse, the sun's heat can get in but not go out. The trapped heat warms the greenhouse and helps in the controlled growth of plants. Similarly, as these gases trap the sun's heat and warm the earth, these gases are called greenhouse gases.
If there were no greenhouse gases to trap the sun's radiation, then our earth would be a very cold place and we would not be able to survive here. This trapping of heat to keep the earth warm is called greenhouse effect.