Читать книгу Common Science - Carleton Washburne - Страница 5

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Why water flows up into your house. It is because water seeks its own level that it comes up through the pipes in your house. Usually the water for a city is pumped into a reservoir that is as high as the highest house in the city. When it flows down from the reservoir, it tends to rise in any pipe through which it flows, to the height at which the water in the reservoir stands. If a house is higher than the surface of the water in the reservoir, of course that house will get no running water.

Why fire engines are needed to force water high. In putting out a fire, the firemen often want to throw the water with a good deal of force. The tendency of the water to seek its own level does not always give a high enough or powerful enough stream from the fire hose; so a fire engine is used to pump the water through the hose, and the stream flows with much more force than if it were not pumped.

Application 2. A. C. Wheeler of Chicago bought a little farm in Indiana, and had a windmill put up to supply the place with water. But at first he was not sure where he should put the tank into which the windmill was to pump the water and from which the water should flow into the kitchen, bathroom, and barn. The barn was on a knoll, so that its floor was almost as high as the roof of the house. Which would have been the best place for the tank: high up on the windmill (which stood on the knoll by the barn), or the basement of the house, or the attic of the house?