According to one of the anecdotes, the English physicist Isaac Newton, lying in an orchard between trees, formulated in the summer 1665 year of universal gravitation. Under this law, all items (also the famous Newton's apple) when lifted above the ground they fall down, on its surface. Only down. They can only go up then, when some force acts on them, a force greater than the force of gravity. Stone then, when we act on it with the strength of our muscles, plane by the power of propeller or jet engine propulsion. Also, water can only drain downwards. And the one from the open tap in the kitchen, and the one in the rivers. After all, no river flows uphill, they all flow to the sea. Is it really? Could there be a mistake in the title?
At least three cases are known, when the water "flows up". We all know the first of them. Flows up, for example. water in the pipes of the domestic water supply. After all, we can take tap water not only on the ground floor, also on the third, and in large cities, even on the tenth floor. Unfortunately, such a statement is untrue. In fact, the water in the domestic system flows according to the law of gravity, so down. Only the principle of communicating vessels was used here, with the water level in one of the vessels (water tower) is higher than the other (domestic plumbing). So the water flows through a system of metal pipes from the reservoir of the water tower and can only be collected in our apartment then, when the tap is lower than the water level in the water tower tank. In our building, the water seems to run upwards”, but under the action of a force resulting from the pressure of the water column in the other arm of the communicating vessels. Fountains work in a similar way. The parks built by people and the natural ones, created by nature - known as artesian wells.
Two other cases, when the water 'flows upwards”, shown in the next figure. The first is a known method of transferring liquid from one vessel to another by means of a tube.
For example. gasoline from the car tank to the canister. The second is a way to water the flowers during the period, when we are not at home, we went on vacation. In the first case, however, it is necessary to suck water into the tube, and the vessel, into which the water is poured, must be on a lower level than the pan, from which the water flows.
So again "something's wrong”. Again, the water flows downward. On a short length of tube, in which it rises upwards, the force resulting from pressure acts in a similar way to a water supply system. Atmospheric pressure this time. More precisely, the force resulting from the difference between the value of the atmospheric pressure minus the pressure of the water column h1, in the upper vessel and the value of the atmospheric pressure minus the pressure of the water column h2 in the lower vessel.