[Richard Kimball]

Alternately, one Atmosphere is roughly equal to 34 feet of water. Try to create a siphon that can lift water higher than 34 feet before it makes it's turn downwards. If the siphon action stops when the lifted column of water exceeds 34 feet, then atmospheric pressure is the root cause of the siphon action.

To take water up a tube that does not have an effective prime requires drafting. Drafting is driven by atmospheric pressure. The maximum theoretical lift at sea level is roughly 33.8 feet. A column of water 1 foot tall exerts .434 psi at the base. 14.7/.434 gives us the 33.8. Siphoning, OTOH, is not dependent upon atmospheric pressure, but on the vacuum created in the hose when water drains out the other end.

If you had to draft to lift your water to start the siphoning process, there would be a maximum theoretical lift. I do not know what the results would be if a 100 foot hose were plugged and lifted over a 35 foot wall then back to below the level of the water in the original container, but I suspect it would still siphon.

[Yo-Yo]

If you had to draft to lift your water to start the siphoning process, there would be a maximum theoretical lift. I do not know what the results would be if a 100 foot hose were plugged and lifted over a 35 foot wall then back to below the level of the water in the original container, but I suspect it would still siphon.

Take a 100 foot hose, fill it with water, and plug one end. Lift that one end, and by the time you have the entire 100 feet of hose in the air, you'd have 34 feet of water in it, and 56 feet of collapsed hose. Can we agree on that?

How does the water flow in this example (shameless ripped off from Wiki) when the plug at D is removed?

What moved the water up the short leg? We then agree that atmospheric pressure had something to do with initating the siphon effect, and the tensile strength of water had zero effect in initating the siphon effect.

Therefore, if the atmospheric pressure effect was so powerful to initiate the siphon effect, it still has that same power to maintain the siphon effect. In most practical siphons, the atmospeheric pressure force greatly overwhelms the tensile strength force in making the siphon work.

Another example of this, also ripped off from Wiki, is the siphon where the short up leg has a diameter much greater than the downard leg diameter, yet the siphon still functions.

Since the weight of water in the shorter up leg exceeds the weight of water in the longer down leg, it is not tensile strength and gravity that is moving the water, it is atmospheric pressure moving it, again pointing to the main force in most practical siphons.

Yet 300 foot sequoia trees prove that tensile strength can move water.

It's a candy. It's a breath mint. Wait, you're both right!