Bubbles Escaping from Submerged Container

Click For Summary

Discussion Overview

The discussion revolves around the challenge of allowing air bubbles to escape from a submerged metal container with small holes in its lid. Participants explore the effects of hole size, surface tension, and container orientation on the escape of air, focusing on practical solutions within constraints of the design.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Gordon describes a problem where air bubbles do not escape from a submerged container with holes, suggesting that surface tension may be a factor.
  • Some participants propose that the orientation of the holes could influence air escape, with suggestions to tilt the container or place holes at different heights.
  • One participant questions the necessity of a flat lid and suggests using tubes to create pressure differences, though this idea is later dismissed due to design constraints.
  • Another participant suggests that a waxy surface might be preventing wetting of the holes and proposes using a detergent to improve bubble escape.
  • There is a discussion about the possibility of adding a hole in the side of the container to facilitate air escape, which some participants agree could be beneficial.

Areas of Agreement / Disagreement

Participants generally agree that the orientation and placement of holes are important for bubble escape, but there is no consensus on the best approach to achieve this. Some ideas are proposed and later challenged or dismissed, indicating ongoing uncertainty.

Contextual Notes

Participants express limitations in modifying the container design and constraints on adding substances to alter surface tension. The discussion reflects various assumptions about the physics involved without resolving them.

gordonb
Messages
4
Reaction score
0
Hi
We have a problem at work where we need to store a metal container under water. The container is to have small holes in the lid to ensure that it floods when submerged but we must minimise the size of these holes. Intuitively, if you have more than one hole in the lid then water will enter one while the air escapes through another but when we've tried it, this is not the case. I'm guessing that surface tension is preventing the bubbles from escaping. So I'm wondering if there is a way to calculate the minimum hole size for a given depth of water to ensure that bubbles will escape from the container.

Hope someone can help.

Thanks

Gordon
 
Physics news on Phys.org
Does the lid have to be flat? I wonder if adding two tubes going in different directions (one inside the container, the other outside) won't help, generating small pressure difference.

But I can be completely off.
 
Thanks for the reply. Yes the lid has to be flat and we don't really have time to make any complex modifications to the can or lid unfortunately.
 
Or, put the container on its side, or tilt it, so the holes are at different levels.

If the two holes are at the same depth in the water, how do the water and air "know" which hole is supposed to be the way in and which is the way out? (there's serious point about the physics and symmetry there, as well as a joke)
 
Can't you use straws?
 
AlephZero, yes, it makes sense that holes would need to be at different heights. That explains why slightly tilting the container causes bubbles to start to appear. We may be able to put a hole in the side as well as one on the top.

JanEnClaesen, no, straws or any similar tube wouldn't be possible.
 
Maybe a waxy surface on the can is preventing wetting of the small hole. You might put one drop of detergent on one hole to see if it makes a difference. If you punch the holes, lubricate the punch with detergent, avoid oil.

There are adjuvants or wetting agents, (eg “pulse”), used with herbicides to break the waxy surface of weeds, maybe adding some such agent to the water before sinking the can will solve the problem.
 
Why can't you have at least one hole in the container itself?
 
I'll try and reply again. For some reason my replies aren't showing up here.

AlephZero, you make a good point. This would explain why we see bubbles being released when the container is tilted as it is lowered.
JanEnClaesen, we can't use straws or anything similar, we have to rely on holes.
Baluncore, unfortunately we can't add anything to break the surface tension but we'll ensure that there aren't any residues around the holes.
SteamKing, yes, based on AlephZero's suggestion I think we will have to put at least one hole in the side.

Thanks to all who have replied.
 

Similar threads

Undergrad Is a half submerged object submerged in its own displaced water?
  • · Replies 22 ·
Replies
22
Views
1K
Shape of a bubble inside a rotating container
  • · Replies 5 ·
Replies
5
Views
2K
Water level in a submerged closed vessel after it is turned upright
  • · Replies 15 ·
Replies
15
Views
4K
Need help- calculating clearing of bubbles from a microfluidic channel
  • · Replies 4 ·
Replies
4
Views
2K
Order of calculations for an air bubble system for dock de-icing
  • · Replies 14 ·
Replies
14
Views
4K
Undergrad Large Bipolar radio bubbles in the Galactic Centre
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Help understanding how my "magic" siphon works....
  • · Replies 17 ·
Replies
17
Views
5K
Undergrad Black hole questions
  • · Replies 29 ·
Replies
29
Views
1K
Exploring End-Use Applications for recycled HDPE from used oil containers
  • · Replies 2 ·
Replies
2
Views
2K
Force on the bottom of the vessel containing a submerged cube
  • · Replies 30 ·
2
Replies
30
Views
4K