I am trying to make an automatic watering system and I have a simple question

Shouldn't the water released from the big bottle stops when the water in the small bottle reaches the tube?

I think the answer is yes no matter what size is the big bottle right?

for some reason it doesn't stop isn't this the same idea as the bird feeder

There is no bobbles coming from the area where the tube entering the big bottle so I thought maybe air is leaking from the big bottle entrance so I tryed to close it hard with my hand but still the water doesn't stop when it reaches the tube

So I came here to check Is it a leaking problem or it shouldn't stop as I thought it should

Thanks for your help and time in advance enter image description here

  • $\begingroup$ Water will not stop until pressure on it from both ends is not equal $\endgroup$ Commented Sep 5, 2021 at 2:30

1 Answer 1


It depends on whether the top of the big bottle is open and if any air can come up the tube.

If the top of the big bottle is sealed, then after a bit of water leaves, the reduced pressure will prevent any more leaving. If that tube is big enough (and straight enough), air could enter the bottle allowing more water to leave. But that tube looks like it might be small enough that wouldn't happen. (And it's certainly not going to happen with that upward bend).

If the top of the big bottle is open, then water is going to drain from there unless you have sufficient pressure to stop it. That small bottle being open to the atmosphere and at a lower level will not provide enough pressure.


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