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Soda Bottle Submarine - HELP!!
I made the soda bottle submarine using a 500 ml water bottle. plastic ruler as a stabilizing fin.
When is this sub supposed to act in neutral/stay level? It sinks at 500 ml water or partially floats when water is removed with the tail up or front up depending on where the air bubble moves from 300-480ml water. Is this neutral/stays level?
Is positive/floats on top of the water completely or is partially okay from 0-300 ml?
Submarine - sink? neutral? float?
Moderators: AmyCowen, kgudger, bfinio, MadelineB, Moderators
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weston
- Posts: 1
- Joined: Tue May 06, 2008 11:23 am
- Occupation: student
- Project Question: Soda Bottle Submarine - HELP!!
I made the soda bottle submarine using a 500 ml water bottle. plastic ruler as a stabilizing fin.
When is this sub supposed to act in neutral/stay level? It sinks at 500 ml water or partially floats when water is removed with the tail up or front up depending on where the air bubble moves from 300-480ml water. Is this neutral/stays level?
Is positive/floats on top of the water completely or is partially okay from 0-300 ml? - Project Due Date: May 12 2008
- Project Status: I am finished with my experiment and analyzing the data
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deleted-71447
- Former Expert
- Posts: 1019
- Joined: Fri Oct 28, 2005 11:43 am
- Occupation: Research Hydrologist
- Project Question: n/a
- Project Due Date: n/a
- Project Status: Not applicable
Re: Submarine - sink? neutral? float?
Hi Weston,
Welcome to the Ask an Expert forum.
I am having a little bit of trouble understanding your question, but I think you are asking about the meaning of "neutral" buoyancy. An object is neutrally buoyant when the density of that object (in your case the submarine) is exactly equal to the density of the surrounding medium (in your case, water). Neutral buoyancy can be observed as the tendency of that object to move in the medium as if it were not under the influence of gravity - if you push it up, it goes up and doesn't sink back down (unless it hits the surface or bumps into something), and if you push it down it goes down and doesn't float back up (unless it bounces off the bottom of your bathtub). In practice, neutral buoyancy can be difficult to achieve because a very small difference in density will cause the object to float or sink. This may be why your submarine seems to float or sink but never to be truly buoyant. You will need to add or remove very small masses to achieve something close to neutral buoyancy.
I hope that helps. Please let us know if there are more questions.
Chris
Welcome to the Ask an Expert forum.
I am having a little bit of trouble understanding your question, but I think you are asking about the meaning of "neutral" buoyancy. An object is neutrally buoyant when the density of that object (in your case the submarine) is exactly equal to the density of the surrounding medium (in your case, water). Neutral buoyancy can be observed as the tendency of that object to move in the medium as if it were not under the influence of gravity - if you push it up, it goes up and doesn't sink back down (unless it hits the surface or bumps into something), and if you push it down it goes down and doesn't float back up (unless it bounces off the bottom of your bathtub). In practice, neutral buoyancy can be difficult to achieve because a very small difference in density will cause the object to float or sink. This may be why your submarine seems to float or sink but never to be truly buoyant. You will need to add or remove very small masses to achieve something close to neutral buoyancy.
I hope that helps. Please let us know if there are more questions.
Chris
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deleted-71588
- Former Expert
- Posts: 1297
- Joined: Mon Oct 16, 2006 11:47 am
Re: Submarine - sink? neutral? float?
You have definitely identified a "sink" state. I suspect you have also identified a couple of "float" states. You can confirm these by pushing the bottle down several inches under the surface and letting it go. If it pops up and breaks the surface, you have a "floating" state.
I doubt you have identified a neutral bouyant state yet. A neutral bouyant state takes some patience to achieve. You might want to consider a way to add balast weight in small amounts without affecting the fluids (air and water) inside the plastic bottle. Neutral bouyancy will be achieved when nothing is touching the bottom and nothing is breaking the surface.
I doubt you have identified a neutral bouyant state yet. A neutral bouyant state takes some patience to achieve. You might want to consider a way to add balast weight in small amounts without affecting the fluids (air and water) inside the plastic bottle. Neutral bouyancy will be achieved when nothing is touching the bottom and nothing is breaking the surface.
-Craig
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truthsayers
- Posts: 8
- Joined: Sun Mar 02, 2008 3:49 pm
- Occupation: student
- Project Question: Effectiveness of magnetic fields and what materials can block their effectiveness
- Project Due Date: March 28,2008
- Project Status: I am just starting
Re: Submarine - sink? neutral? float?
From: Austin
To: Weston
Dude your experiment is one that actually catches my attention. Can you tell me your whole experiment again. I couldn't quite get it, but by what I understand it's pretty awesome. YOU should try putting fizzy sprite in the bottle and letting it out in the bottom of the water. It would probably be a cool experience.
To: Weston
Dude your experiment is one that actually catches my attention. Can you tell me your whole experiment again. I couldn't quite get it, but by what I understand it's pretty awesome. YOU should try putting fizzy sprite in the bottle and letting it out in the bottom of the water. It would probably be a cool experience.