The sun — not only the star, closest to Earth, but also a source of heat and light for all Solar system. Therefore it is quite natural that scientists develop technologies of practical use of solar energy for a long time and achieved in it considerable success.
Instruction
1. Historically the first began to use solar energy of a plant. Chlorolayers are the tiny green little bodies which are contained in their cages — the real industrial centers where energy of sunshine serves for synthesis of glucose from water and carbon dioxide. In addition as a by-product of a plant emit the oxygen necessary for almost all living beings for breath. These natural "solar factories" can be included in technological processes. For example, the monocelled green seaweed living in special pools can become raw materials for production of fuel or even artificial food.
2. A hotbed — other way to use solar heat. Its transparent walls pass thermal radiation inside, and the closed space does not allow heated air to come to light. Usually hotbeds use in agriculture, but it not their only application. The sun with success heats also water for bathtubs.
3. To receive more high temperature, sunshine need to be focused in one point. Sometimes for this purpose use lenses, but concave mirrors are much more practical. Even the usual design from several flat mirrors from which "hares" are sent to the same place allows to boil water on clear sunny day. And the correct parabolic mirror with a diameter of two and a half meters collects so intensive light in focus that with its help it is possible to melt metals.
4. Some substances have photoeffect — if to light them, then they begin to develop electric current. Electricity source created on the basis of such substances is called a photo cell or the solar battery. It directly transfers energy of light to electric energy though its efficiency and is not really high. Silicon photo cells are used, for example, for power supply of desktop calculators for a long time. More serious solar batteries give enough electricity for the whole house. Usually they are placed on roofs that on them the shadow never fell. Naturally, at night the solar battery stays idle, but electricity which is saved up by it in accumulators in a day, quite lasts for night-time.