# Siphon Question

• B
What affects how fast the water come out of the tube?(size of tube, size of opening where the water enters, etc) thanks in advance.

berkeman
Mentor
What affects how fast the water come out of the tube?(size of tube, size of opening where the water enters, etc) thanks in advance.
Welcome to the PF.

What are your throughts? What do you think are the main things that affect the flow rate?

Well my first thought is that the size of the tube is what would affect the flow rate. So if I wanted to increase the flow rate I would have to increase size of the hose, but what I am not to sure about is could I make it flow faster just by increasing the size of the first part of the tube? I would have to imagine that to some degree if you had a big enough tube and connected to a smaller tube it would flow faster. Maybe not fast enough to be similar to what would come out of a hose bid, but I am thinking it should be faster because there would be more water "behind" the smaller tube. But then again I know for water to faster through a smaller tube there has to be enough pressure to behind the smaller tube to actually push the water and not just siphon water(basics of a pressure washer). So is it possible to increase the flow rate by just increasing part of the tube?

berkeman
Mentor
Well my first thought is that the size of the tube is what would affect the flow rate. So if I wanted to increase the flow rate I would have to increase size of the hose, but what I am not to sure about is could I make it flow faster just by increasing the size of the first part of the tube? I would have to imagine that to some degree if you had a big enough tube and connected to a smaller tube it would flow faster. Maybe not fast enough to be similar to what would come out of a hose bid, but I am thinking it should be faster because there would be more water "behind" the smaller tube. But then again I know for water to faster through a smaller tube there has to be enough pressure to behind the smaller tube to actually push the water and not just siphon water(basics of a pressure washer). So is it possible to increase the flow rate by just increasing part of the tube?
The pressure comes from the "head" or difference in heights of the two water surfaces. Using a bigger tube allows more water to flow for a given height difference. If the tube necks down, you still have the same pressure pushing the water, but less area to let the water flow through.

https://myelms.umd.edu/courses/969642/files/27532357?module_item_id=6128404

Jcirish
Well that sucks. Thanks for your help.

berkeman
Mentor
Well that sucks.
Funny double-meaning!