h a l f b a k e r yPoof of concept
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Everyone by now has an attractive Globe-Fish-In-Sphere at home or at work, thanks to [lostdog], with an eager-to-please female goldfish ("Goldie") in residence.
Our collective excitement turned to disappointment though, when we realized that Goldie doesn't move. Or rather, Goldie moves around fine
within her little world, but her world doesn't move with her. It just sits there.
Physics has gotten the better of Goldie. She possesses neither the strength, speed, stamina nor the concentration to engage in the furious whirling and elf-hurling necessary to create the twirling vortex that might spin her world off its perch.
And despite all the instructional tapes, hypnotic conditioning videos, training sessions, memory-enhancement pills and even private tutors, Goldie still shows no capacity to retain the complex, counter-intuitive choreography required to roam his globe around using the bladder-bloating density adjustment techniques.
Some have tried painting Goldie black, to take advantage of potential thermo-dynamic air pressure forces that might get things moving. But even after you finally find the right paint mixture and fattening food, Goldie XVIII is indifferent, and you suspect that your space has too much ambient turbulence from Fido and the rugrats for Goldie's corpulent black surface area to make any difference, air-pressure-wise.
You've searched everywhere for an inexpensive optical sensor and roller motor system, but the only one you googled for less than $1000 had a lot of dangerous-looking exposed electrical wires. Don't want to fry Goldie.
No need to flush it all down the toilet yet. Here's a simple, mechanical-based add-on kit that turns your static Globe-Fish-In-Sphere (G. F.I.S.) into a real F.I.S.H. Propulsion System.
WHAT YOU GET:
One (1) clear plastic circular ring with four small horizontal piston-fitted cylinders fixed around the circumference at 90 degree intervals, extending inward. The apparatus is sized to fit just inside your sphere at its widest diameter.
One (1) adjustable fish harness, connecting by fish line to each of the pistons. The water-tight sealed cylinders each have a slender air hose arcing up to the north pole, so to speak, if the ring were the equator.
INSTALLATION:
Drain half the water and unscrew the hemispheres to open your globe (you did buy the model with the polar air/water valves and equatorial schism, didn't you?). Install the kit by laying it into position inside the globe (there should be about 1mm clearance on all sides of the ring). Gently fasten Goldie into his harness, make sure the fish lines are adjusted correctly and connected to each piston, then reassemble the globe, and refill.
IMPORTANT: Remember to leave approximately 30 cc of air at the top of the globe.
HOW IT WORKS:
Goldie simply does the thing that goldfish do: she roams around her world, rediscovering everything every 5 seconds. And thanks to the fish-line tethers on his harness, each direction she swims inside her world causes the globe to roll in that direction also.
As she swims to the eastern end, for example, she pulls the piston on the opposite side, drawing into that cylinder 20 cc or so of air from the air pocket in the top. The water level rises due to displacement of 20 cc of water, and the water mass in the globe is now imbalanced. (Goldie's eastern hemisphere now contains 40 more cc of water, and thus has 40 more grams of mass, than the western hemisphere.) The globe rolls east, until Goldie spots something in a different direction.
This idea thanks to [lostdog] for inspiration and [RayfordSteele] for key technical advice.
The Original Roaming Goldfish Bowl
http://www.halfbake...g_20Goldfish_20Bowl
Thanks to lostdog [roby, Oct 04 2004, last modified Oct 05 2004]
Similarly designed Perpetual Motion Machine...
http://www.lhup.edu...um/annex.htm#korean
...that doesn't work ("at hb, we obey the laws of thermodynamics") [roby, Oct 04 2004, last modified Oct 05 2004]
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The objections raised earlier all stand. You are moving a larger mass than the fish, and the motive power is still miniscule. |
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Maybe you should outfit the goldie with drawers over his pants, bestow super fishial powers on him and call him Phantom. |
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[neelanden] Yeah, Goldie might want to get some time in at the health club and some nice work-out togs, if she's going to be pulling pistons all day.
But Goldie's mass has nothing to with the propulsion. As long as she can draw air into the cylinder, the mass imbalance is based on the volume of water displaced, not her mass (Goldie's mass is the same as an equal volume of water).
Here's an example: Imagine a well-engineered low-friction solid sphere with a large air cavity off-center. Its mass is imbalanced, and when you set it down, it rolls until it settles with its center of gravity vertically aligned with the air pocket. If you tip it, it wants to return to that center of gravity position.
The F.I.S.H. kit just allows Goldie to create an air pocket that stays off center, and keeps the sphere rolling.
If water pressure made it too difficult for Goldie to pull the pistons, we would reduce the circumference of the ring so it would float closer to the surface of the water. |
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What the heck; I'll take two. |
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I would think you'd only need one piston, behind Goldie, since he'll hardly be swimming sideways or in reverse. |
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This idea definitely isn't getting what it deserves...me dad and i read this and have been working on it as a perpetual motion device...tips are good and intelligent annos are better. much love everyone |
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[igirl] Thanks, but perpetual motion machines not possible. At a minimum, this requires the constant efforts of Goldie swimming against buoyancy of the piston behind her. Fish have to stop to eat.
[farmerjohn] I thought I'd give Goldie a bit of slack (literally) and a nice swivelly multi-fishline attachment to the harness, so she would be free to swim quad-directionally, if not omni-directionally. |
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HELP! Now this idea is driving me crazy.
I strongly suspect it won't actually work, but not for the reasons I've heard yet.
Halfbakers who actually took science in school (and the fishboners who've voted no here without stating reasons): what is the flaw?
igirl's reference to dreaded PM device tells me I'm on the wrong track. I could weight the ring to keep it closer to horizontal to counter buoyancy driving cylinder end of ring up...but there's got to be something else wrong...
Ideas? |
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I don't quite get it. I'm assuming in the swimming-east example the west piston is filling with air, causing that side of the plastic tube to rise. But won't that just flip Goldie over? |
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I say we try to bake it. We'll need beta beta testers, of course. |
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The problem is that you're trying to increase mass to the east by an air pocket to the west, but have to hold the air under the surface with a weight. The air pocket tilts the weight slightly to the west giving equilibrium and thus no imbalance or rolling. |
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Its a good idea but as u said it prob wouldnt work and the potential hazzard of the fish mobility ball falling down a stair well, and im pretty sure the initial shock of this will kill the fish in question. |
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Getting somewhere, thanks.
[farmerjohn] is on track, and [Worldgineer] nails one definite problem. So say I dangle a 30g weight from each cylinder on a short line. When the west cylinder fills with 15cc of air, it's still going to start to rise up despite the weight because the east 30g weight is countering the west 30g weight...UNTIL...the ring tilts 45 degrees or so and the east 30g weight rests against the slope of the sphere, and its vector isn't pulling its end of the ring down as well as the still vertical vector of the dangling west weight. Thus keeping the 15cc of air in the cylinder submerged and maintaining the east-west hemispherical mass imbalance.
No?
I have no doubt this idea is fatally flawed, but I'm not mad scientist enough to get it yet.
[cedarpark] I may have to go to the pet store and get one of those gerbil globes and build a fishless prototype with wire ring and one fixed open cylinder. What the heck, I'll put a fish in there just for fun. Fish harnesses still out of stock last time I was there, though. |
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Fill the house with water. Tether Goldie to the outside of the ball (once s/he's had some counselling to overcome h/is/er sexual identity crisis) and fill the ball with just enough water to achieve neutral buoyancy. Watch the ball move wherever Goldie's whim determines. |
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Then put a guppie in Goldie's globe as a pet for him/her/it. |
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//Fill the house with water// |
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You might find this unnecessary. It is unlikely that Goldie is able to see further than a few feet in any direction. Therefore, if Goldie could be given an infinite world by carefully balanced inlets/pumps in a large spherical tank balanced by sensors that detect its position relative to the center. |
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<cue screaming goldfish effect> |
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Holodeck for goldfish ? Cool ..... |
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By neptune, I think he's got it! I can't see any reason why it won't work from a theory standpoint; it's simply the strength of the fish and the practical design of the cylinders / harness / etc. that become issues. |
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There need to be pistons on 6 sides to continue motion. Goldies harness can be mounted in gymbals, like a gyroscope, to allow freedom of orientation. |
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What Goldie is essentially doing here is displacing a volume of water at a certain pressure with an equivalent volume of air. This effectually raises the water level in the bowl as the air is displaced to the side. But the fish would need to be theoretically strong enough to pull against the pressure differential of creating a large bubble underwater, like trying to sink an air-filled water-toy. |
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Here's an improvement to toy with, though I haven't worked out the details. Instead of trying to displace air from the top of the bowl, simply start with the cylinders in front and in back of Goldie at half-throttle, and connect them to the air distribution system somehow. Use gravity-oriented / activated valves to close off the top cylinder, so that air doesn't go up there. As a matter of fact, simply pair up the opposite cylinders through air tubes somehow. |
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Now as Goldie moves forwards, she pulls the back cylinder out, which gets its air from the front cylinder, which consequently moves forwards to fill the vacuum. Now the only force Goldie has to overcome is static friction, no pressure differentials to worry about beyond transients. |
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Rollin...rollin...rollin... keep them dogfish rollin.... |
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I like egbert & igirl's collaboration the best. Think of the freudian implications of that!
[RaySteele] rocks. Thanks for adding brilliant elegance to bizarre fantasies. Though fish who live in glass bowls shouldn't throw rocks.
For those still curious and contemplating fabrication orders, see the link from prolific and entertaining Perpetual Motion debunker at left.
The baby may rock, but it might not roll. |
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Guys take a look at this toilet contracption from the UK www.airloo.com it was patented last year and has taken off in the UK very well. |
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The airloo sucks all the smells out of the bowl and either filters it or pushes it outside. |
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