This easily made solar water heater shows you how the sun heats the water and how it circulates. Its just a panel and a tank, and two pipes connecting the two, thats all.A Minimum system. Hot water rises, and cold water falls. As the water circulates it drops its heat off at the top tank, and the colder water in the bottom of the tank drops to the bottom of the solar panel to be heated by the sun and rise up again, and gradually the tank fills with hot water, as if by magic, and of course it is, its real magic. Oh, forgot to say, that because its a direct system, ie., you use the same water that circulates, you have to make sure you put at joint at the bottom with a screwed cap on it, so that you can drain all the water out of it, before the frosts come in the winter, because the expansion of ice forming in the water will break everything. During the winter we use a kettle to heat the water on a wood stove. One kettle mixed with cold water does a good shower.