Syphon how does it work

There is no drain. You don't have a bucket. All you have is a simple garden hose. Can you put science to work for you? Using what you know about siphons, how can you empty the hot tub? Did you get it? Test your knowledge. Wonder Words pool drain hose flow pump crop level canal channel purity force vacuum agriculture irrigation particle atmospheric pressure cohesive Take the Wonder Word Challenge.

Join the Discussion. Michael T Apr 4, Apr 16, Thanks for sharing, Michael T. Michael T Mar 10, The perfect siphon hose would have a control valve at the crest. This is made possible by adding anti-backflow check valves to the inlet and outlet to allow the liquid to flow in the direction to the outlet while preventing air from entering and breaking the siphon when the shutoff valve is closed.

Once the siphon is initially primed, the system will stay primed if air is not allowed to enter at the inlet. Andreas Jan 29, Michael Feb 7, The perfect controllable siphon hose would have a foot check valve at it's inlet and a shutoff valve at it's crest and an anti-backflow valve at it's outlet.

Once this siphon is filled and primed, it would work automatically by opening and closing the shutoff valve. The hose would stay primed as long as air was not allowed to enter the line. Feb 8, Michael Taylor Aug 8, Siphon's can run perpetually using only their own power. The only true perpetual motion machine that continually causes mechanical motion is a Siphon with a Metering Chamber and US Patent discloses this in figure number four of the art.

Timing and the weight of the water allows for a continuous water flow above the source. Aug 13, Thanks for sharing, Michael! This was very interesting! Could you maybe do a wonder about computer code? I would find that even more interesting.

Nov 15, Caleb Jan 5, That experiment is cool, is it safe to do without my parents? Jan 6, Dec 16, Jace Nov 24, Nov 26, Jace Nov 30, Dec 2, Related Wonders for You to Explore Match its definition: a large-scale farming enterprise. Word Match Congratulations! Share results. In order for the siphon to work, the source liquid must be elevated above the container you're trying to transfer it to.

Remember, gravity is doing the work here. Feed the hose into the source tank and put your secondary container on the ground. You can do this with your mouth, but this is a bad idea if you're siphoning gas. To avoid air bubbles when sucking out the liquid, hold up your siphon tube vertically—this will give the bubbles a place to escape. If you want to skip sucking altogether, submerge the entire hose in the source tank, then place your thumb firmly over the delivery end.

In this case we must be clear about the reason that the siphon would fail if the U-tube were too high. It is simply because air pressure on the input side is insufficient to raise the input liquid column as high as the top of the tube. If it doesn't get to the top, it won't flow over to fall down the output tube.

So air pressure is important to siphons by putting a limitation on how high they can lift water, and without lifting the water to the top of the U-tube, no siphon flow can occur. What sustains the liquid flow? But this isn't the whole story. Is it air pressure that sustains the water flow in a siphon? It is not. If siphon flow is analyzed, with a nearly incompressible liquid like water, the work done at each end of the siphon against air pressure is NET zero, for equal volumes of air are displaced at each end.

The two ends water surface in bucket and at the output end of the tube are both at the same atmospheric pressure, p , so pdV is the same size for equal volumes displaced, but the signs are opposite. So air pressure does not drive the siphon. Siphoning in a vacuum. If there were no air pressure, could a siphon work? Yes, at least for some liquids, but something else would be required to cause the liquid to form a continuous path through the elevated U-tube.

Very cohesive liquids can do this, the molecules attracting each other so strongly that they can maintain a chain-like continuity up and across a U-tube, yet still maintain liquid properties. This has been demonstrated in the laboratory. See: Siphon in a vacuum. So continuity of the liquid in the U-tube is essential for a siphon. The continuity can be sustained by external air pressure, but even in the absence of surrounding air, cohesive forces in some liquids are sufficient to pass over a modest height of the U-tube.

So we can conclude that air pressure is not always necessary to provide the conditions necessary for a siphon. But air pressure is never the reason that the liquid maintains flow through the siphon tube, for any kind of liquid. The naive chain analogy. Maintaining the flow. Let's suppose we have the conditions necessary for a siphon, with liquid from the reservoir filling the tube. The output portion of the U-tube is necessarily longer than the length of the input portion measured from liquid level to top of U-tube.

So it is all too tempting to think of this as something like a pulley and rope with unequal weights attached to the rope on either side. Then the heavier weight "pulls down" the other one. This misconception is reinforced by thinking of the liquid in the tube by analogy with a smooth and flexible chain passing over a pulley. But that's the danger of naive analogies, they ultimately break down, for the two situations are never completely alike. A failed siphon model. A few years ago a journal article stimulated some controversy in journals and on the web.

Hughes, Stephen W. Physics Education, 45 2 , pp. Hughes exposed a serious error in dictionary definitions of "siphon", especiaially The Oxford English Dictionary definition: "A pipe or tube of glass, metal, or other material, bent so that one leg is longer than the other, and used for drawing off liquids by means of atmospheric pressure, which forces the liquid up the shorter leg and over the bend in the pipe. But Hughes went on to propose cohesion and the "chain model" as the reason for siphon flow, ignoring the role of liquid pressure gradients.

This chain model was refuted. See: Siphons, Revisited. Alex Richert and P. Binder, University of Hawaii at Hilo. The Physics Teacher, Vol. Reverse siphon? Vittorio Zonca's mill. From Dircks The chain model treats the siphon flow as due to different weights of liquid in the two siphon arms.

If it were the weight in the arms of the U-tube that causes and sustains liquid flow, then this hypothetical reverse siphon Fig. In fact this ought to allow a siphon to raise liquid from lower to higher levels. Vittorio Zonca , In his folio Novo Teatro di Machine et Edificii Padua, even proposed this idea as if it could be a useful device to lift water to drive the waterwheel or turbine of a mill.