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## Question

An underground pool is located on a hill that's 20 ft. above sea-level. The pool is surrounded by a 5 ft. fence. The bottom of the pool goes no lower than 10 ft. above sea level. The pool's owner notices that the pool could use about 10 more gallons of water. So he stands at the base of the hill holding a hose that goes up the hill, over the fence and into the pool and pours the water into the hose and begins to fill up the pool. After he pours all the water into the hose he drops his end onto the ground and walks away.

What happens and why?

## 8 answers to this question

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None of the water should have gone into the pool in the first place. Even if he could somehow make the water go up the hose to the pool, as soon as the water was enough to displace the distance between the pool water and the fence, it will siphon the water out to the bottom of the hill. It will continue to do this when he walks away.

As for why, gravity.

Edited by Noct

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Noct stop solving my puzzles! j/k You're right except for the reason. There is more to a siphon than gravity. It also accounts for total distance in height and (most importantly) air pressure into account. Gravity alone would not do the trick. Good one though

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Noct stop solving my puzzles! j/k You're right except for the reason. There is more to a siphon than gravity. It also accounts for total distance in height and (most importantly) air pressure into account. Gravity alone would not do the trick. Good one though

Good to know!

I was never sure of the exact physics of it, but I knew that the water will flow from the higher place to the lower place, even if it has to go up to get there (up to a maximum of 32 feet up)

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the water from the pool starts to come through the pipe , maybe?

coz the pool's ned is lower than the other end

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itachi-san: siphon effect is due 2 factors, a. gravity which gives the water in the pool the "head" it needs to store energy(potential energy) and b. the lack of air in the pipe which causes the waer to flow our so easily. This puzzle reminded me of my road trip when my friends ran out of gas and I had to siphon out some gas from my own tank to put some into theirs'.

Edited by chanakyavg

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chanakyavg is right. also the air pressure on the pool pushes the water down and into the lower pressure hose where it will siphon down to the bottom of the hill.

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itachi-san: siphon effect is due 2 factors, a. gravity which gives the water in the pool the "head" it needs to store energy(potential energy) and b. the lack of air in the pipe which causes the waer to flow our so easily. This puzzle reminded me of my road trip when my friends ran out of gas and I had to siphon out some gas from my own tank to put some into theirs'.

My mother was also a tank driver

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I agree with noct, unless you have a water source 25 feet above the bottom of the hill no water will go in the pool anyway.

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