Two tpes of energy that come from the sun are heat and light. The sun's energy heats things up, our homes, our cars, our bodies and it can also heat or cook food in solar cookers, this is called thermal energy. Thermal means heat, solar thermal energy means heat from the Sun. Light energy is using the sun and turning it into electricity this is photovoltaic. Light energy makes our solar calculators work and can light our homes with the help of solar panels or photovoltaic cells. "Photo" meaning light and "voltaic" meaning electricity. Thermal energy is passive solar energy and photovoltaic is active solar energy. Passive solar energy uses no mechanical devices to put out heat, it uses large windows, brick walls, stone flooring, anything that collects heat from the sun naturally. Active solar energy relies mainly on three things; a solar collector, a solar storage system and a heat transfer system. Active solar systems are very expensive to install because they need more than the natural light, they need mechanics to make it work.

Sunlight passes through the earth's atmosphere and warms the earth, heat rises from the surface and warms the atmosphere. Gases in the atmosphere absorb some of the heat and reflect it back to the ground. This warming process is the greenhouse effect. The greenhouse effect keeps the earth's atmosphere at 15º C. If there were no greenhouse gases in the atmosphere the earth's temperature would be -18ºC, it would be to cold for most things to live. We do need greenhouse gases but humans are polluting the earth and sending too many greenhouse gases into the atmosphere. The earth's temperature is heating up, this is global warming. Since 1880 when accurate temperatures have been recorded, the earth has heated up .5ºC. This temperature does not sound like much of an increase but it is causing a rise in sea level, a change in rainfall patterns and in our weather. This has an impact on wildlife, plants and humans. Every little bit that we do as humans to prevent pollution will help. Don't think that you won't make a difference because everything you do to prevent pollution will help our home, the earth.