# Weird question about siphons; need help!

1. Jan 26, 2005

### CoolHandLuke

I obviously lack an understanding of the fundamentals here; maybe someone can help me out.

So I'm making a siphon, only instead of using one tube, I'm using a set-up where, due to changes in the tube size, the short end has 3.5 times as much water as the long end. It's not significantly shorter or anything, just a bit. And the bottom is narrowed back down. (I've tried it without narrowing the bottom back down to the same width as the long side, as well.)

According to my physics teacher, siphons work because of the weight of the water and the air pressure on the surface of it. So why then, on my siphon, would the short end not fall due to its having more weight and create the vacuum on the long end?

I guess it has something to do with both sides wanting to fall, independent of the weight of the other side. Hopefully somebody can explain this to me.

2. Jan 26, 2005

### BobG

I'm a little lost on how you've designed your siphon, but the water level on either side of the siphon is the important thing.

The water level at both ends of the siphon will attempt to reach the same level. In other words, it's not just the weight of the water in the siphon - it's the weight of the water on either end of the siphon.