Small scientific experiment The principle by which water flows to higher places is the siphon phenomenon.
1. The siphon is filled with water, there is no air, the water level at the inlet end is high, and the water outlet is closed with the palm of the hand or other objects. . At this moment, the pressure inside the pipe is equal everywhere. Once everything is installed, open the water outlet. Although the air pressure on both sides is equal, the water level at the inlet end is high and the pressure is strong, causing the incoming water to continuously flow out of the outlet.
2. Since the surface of the pipe mouth is subject to different atmospheric pressures, the water will flow from the side with higher pressure to the side with lower pressure until the atmospheric pressure on both sides is equal and the atmospheric pressure is equal. The surfacewater in the container reaches the same height and will stop flowing. The water contained in the container can be quickly pumped out thanks to the siphon phenomenon.
The definition and causes of the siphon phenomenon
1. The definition of the siphon phenomenon
1. The siphon phenomenon uses the pressure difference. The principle is that the liquids contained in a closed container have the same height and the same pressure. The siphon is filled with water and has no air. The water level at the inlet end is high, and the water outlet is closed with the palm of the hand or other objects. Once everything is installed, open the water outlet. Although the air pressure on both sides is equal, the water level at the inlet end is high and the pressure is strong, causing the incoming water to continuously flow out of the outlet.
2. The siphon phenomenon is caused by the gravitational force and the potential energy differenceit between liquid molecules, that is, the pressure difference of the water column is used to make the water rise and then flow to a lower place. . Since the surface of the pipe mouth is subject to different atmospheric pressures, the water will flow from the side with higher pressure to the side with lower pressure until the atmospheric pressure on both sides is equal and the surface of the water in the container reaches the same height. , and the water will stop flowing.
2. Causes of the siphon phenomenon
1. In fact, the siphon effect is not entirely caused by atmospheric pressure. The siphon phenomenon can also occur in a vacuum. The force that causes liquids to rise is the cohesion of the molecules between the liquids. When siphoning, because more liquid flows out of the tube than enters, the gravity on both sides is unbalanced, so the liquid continuesto flow in one direction.
2. Liquid flows through the tube and the pressure decreases as it increases. If the tube through which the liquid rises is very high, the pressure will drop enough to cause bubbles (made up of air or other gases) to form in the tube. The height of the siphon is determined by the generation of bubbles.
3. Because the bubbles will disconnect the liquid and the force between the gas molecules at both ends of the bubbles will be reduced to 0, thus destroying the siphon effect, the tube must be filled with water. Under normal atmospheric pressure, the siphon works better than under vacuum, because the atmospheric pressure on the nozzles on both sides increases the pressure inside the entire siphon.
4. The liquid cannot resist negative pressure, that is, the height difference cannot be too large (10 m under atmospheric pressure), but in fact there is cohesion betweenliquid molecules and can withstand some negative pressure. , but there is a certain limit, and under negative pressure, the liquid column will break at the slightest disturbance.