Working mechanism of straws and siphon

  • Thread starter Thread starter sss1
  • Start date Start date
Click For Summary
SUMMARY

The discussion clarifies the working mechanisms of straws and siphons, emphasizing the role of differential pressure and gravity. In a siphon, the liquid flows continuously due to the exit point being lower than the liquid source, creating a sustained differential pressure as air is removed from the pipe. Conversely, a straw relies on the user creating a temporary differential pressure; once suction ceases, the flow of liquid stops due to the lack of pressure difference. This fundamental distinction explains the continuous flow in siphons compared to straws.

PREREQUISITES
  • Understanding of fluid dynamics principles
  • Knowledge of pressure differentials
  • Familiarity with gravity's role in fluid movement
  • Basic physics concepts related to suction and flow
NEXT STEPS
  • Research fluid dynamics and pressure differentials in liquids
  • Explore the principles of siphon design and applications
  • Learn about the physics of suction and its effects on liquid flow
  • Investigate practical experiments demonstrating siphons and straws
USEFUL FOR

Students of physics, educators explaining fluid mechanics, and anyone interested in the practical applications of siphons and straws in everyday life.

sss1
Messages
50
Reaction score
2
Homework Statement
What's the difference in the working mechanism between a straw and a siphon? Why do you only need to suck on the siphon once for continuous flow of the liquid whereas if you stop sucking on a straw then liquid stops flowing?
Relevant Equations
NA
Is it because for a siphon since the end where the liquid exits is lower than the container level so when the pipe is sucked all the air in the pipe is gone and so liquid moves due to differential pressure, and gravity pulls the liquid down, removing the air in the pipe as the liquid comes down, so this differential pressure is maintained so the liquid just keeps flowing down? Whereas for a straw when you stop sucking on the straw there is no longer a differential pressure to keep the liquid flowing?
 
Last edited:
Physics news on Phys.org
Watch this video and answer your own question.

 

Similar threads

Make 2 launchers that shoot a straw with clay at the end
  • · Replies 3 ·
Replies
3
Views
1K
What is the solution to the straw paradox?
  • · Replies 9 ·
Replies
9
Views
3K
Low Viscosity Oil, Tanks, Pressure Relief Valves and Check Valves
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Help understanding how my "magic" siphon works....
  • · Replies 17 ·
Replies
17
Views
5K
The phenomena of Siphons - Directional check valve prevents siponing
  • · Replies 2 ·
Replies
2
Views
2K
A Siphon at the Bar: Jane's DIY Drink Mixing Trick
  • · Replies 11 ·
Replies
11
Views
10K
Fluid dynamics: half submerged straw opening
  • · Replies 9 ·
Replies
9
Views
3K
Problem with my Venturi operated Drum Vac
  • · Replies 11 ·
Replies
11
Views
3K
Undergrad What Keeps Water in a Straw When It's Removed from a Glass?
  • · Replies 12 ·
Replies
12
Views
5K
Problem about Hagen-Poiseuille law and pump
  • · Replies 15 ·
Replies
15
Views
5K