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Old 20-07-2009, 06:16 PM
Lunven Lunven is offline
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First recorded activity by GardenBanter: Jul 2009
Posts: 1

Originally Posted by jonk View Post
I do not believe that a siphon will work for you as you suggest -- in case you have not already tried with a mini-model of your own.

Siphons take water from one level to a lower level *only* thanks to gravity and water's affinity for itself (surface tension is extremely strong). it is this latter property that makes one molecule want to follow the others out the lower end of a siphon once you get it started, and that "pulls" the water along over the hump.

You are attempting to show the outlet side (where the o's start) to be higher than the inlet. this is not a siphon -- unless you reverse it :=)

you can experiment with a simple clear plastic tube and two glasses, one filled with water to start and elevated on a physics book or two. simply start the siphon by sucking on the open end to get the water over the "hump" and then let the free end lower into the empty glass. as the siphoning works, play with the outlet end in terms of its height in relation to the inlet end in the glass of water. you will quickly realize that, as you raise the outlet end above the inlet end, the siphon will slow down and eventually stop.

now, you could certainly make a free-standing, siphon-based fountain that could last "x" amount of hours or days given you had a big enough reservoir that you re-filled every so often (you could even hide it miles away and have it be much more than a trickle fountain). but you cannot make a fountain that is self-contained and "energy-less."

Some cool links for gravity-fed fountains:
from 1840's:
and from the 1720s:
If the siphon has to drain to a reservoir LOWER than the pond then why not put a drain in the bottom of the pond and let it go to a skim with filters lower than the pond. BUT the skim would be very tall, slim and bottom filling. The top of the skim that would overflow back into the pond would be slightly taller than the pond. This would be the waterfall.

So one would have to get a tall skinny skim and position the bottom of it lower than the drain in the pond. Attach the hose upon siphoning to the bottom of the low skim. As it fills up would it fill from the bottom,filtering through the sponge material to overflow at the top back into the pond perpetually?