merrill@raja.DEC (Rick) (03/26/85)
The Kappa Sigma Perpetual Motion Machine Ground rules Now that a team of six critical volunteers has been identified (you know who you are) here is the description. But first two ground rules: Please keep all replies to net.phisics [let's keep this out of net.religion:-)] and please, no arcane formula - use English, ok? Description Consider an unfinished tower at the edge of a river. Hydrolysis is performed continuously on some water from the river and the subsequent oxygen and hydrogen gasses are stored in balloons, which being lighter than air rise to the top of the tower where the balloons are burst and a spark ignites the gasses which combine into water. The water is permitted to fall through a vacuum tube into a turbine which generates twenty percent more electricity than is needed to operate the aforementioned operations. Theory Gravity works for us in two directions. First by creating a pressure gradient in the atmosphere that gives hydrogen and oxygen negative potential energy and secondly by giving water positive potential energy. Discussion The fraternity economist stalks out declaring the payback period is too long. The chemist declares that products of hydrolysis do not balance and that the combustion is incomplete. The skydiver begins mumbling about "terminal velocity ... vacuum ?" The EE asserts that no turbine can possibly be made to the required efficiency. The Natural Sciences major begins to rant about upsetting the ecology of the river, and the MBA wants to know who's vice president of the whole operation! Rebuttal For every energy loss, for any inefficiency, for each diminished return there is but one response: . . . . . BUILD THE TOWER HIGHER !
jeff@rtech.ARPA (Jeff Lichtman) (03/26/85)
> > The Kappa Sigma Perpetual Motion Machine > > Description > > Consider an unfinished tower at the edge of a river. Hydrolysis is performed > continuously on some water from the river and the subsequent oxygen and > hydrogen gasses are stored in balloons, which being lighter than air rise > to the top of the tower where the balloons are burst and a spark ignites the > gasses which combine into water. The water is permitted to fall through > a vacuum tube into a turbine which generates twenty percent more electricity > than is needed to operate the aforementioned operations. > > Rebuttal > > For every energy loss, for any inefficiency, for each diminished return > there is but one response: > BUILD THE TOWER HIGHER ! It takes energy not only to separate the hydrogen from the oxygen, but also to displace the air when the gases are created. The energy that goes into displacing the air is stored as buoyancy, a form of potential energy. You can't get more energy back from the buoyancy than you put in; building the tower beyond this point won't do any good, because the balloon won't float above there. So the energy you get back from the falling water will at best equal the energy it takes to displace the air, no matter how tall you build the tower. When you burned the hydrogen and oxygen at the top, you threw away the energy from the heat of combustion. This energy is equal to that required to separate the molecules. Since you throw away this energy, you won't have it available at the bottom to separate more water. Nice problem. -- Jeff Lichtman at rtech (Relational Technology, Inc.) aka Swazoo Koolak
hennessy@nmtvax.UUCP (03/27/85)
In reference to electrolizing water, putting it into a ballon, letting it rise, pop, and recombine into water, fall down the tower and drive a turbine to produce more energy than to electrolize the water I offer the following points. 1) The electrolizing of water will take more energy than in the gravitational potential of said mass of water. 2) Work must be done in putting the O2 and H2 into the ballon, thus more energy is required. 3) Friction in the system will kill you. 4) As building the tower higher, the earth has a one over radius squared field which means the integral to get potential converges reducing the pratical limit to build the tower. Sincerely; Greg Hennessy ..ucbvax!unmvax!nmtvax!student ..ucbvax!unmvax!nmtvax!hennessy
curry@hplabsc.UUCP (Bo Curry/guest) (03/28/85)
O2 is heavier than air, not lighter.
Bo hplabs!currygraner@ut-ngp.UUCP (Nicolas Graner) (03/29/85)
In <1264@decwrl.UUCP>, merrill@raja.DEC writes : > The Kappa Sigma Perpetual Motion Machine > > Description > > Consider an unfinished tower at the edge of a river. Hydrolysis is performed > continuously on some water from the river and the subsequent oxygen and > hydrogen gasses are stored in balloons, which being lighter than air rise > to the top of the tower where the balloons are burst and a spark ignites the > gasses which combine into water. The water is permitted to fall through > a vacuum tube into a turbine which generates twenty percent more electricity > than is needed to operate the aforementioned operations. > Theory > > Gravity works for us in two directions. First by creating a pressure gradient > in the atmosphere that gives hydrogen and oxygen negative potential energy and > secondly by giving water positive potential energy. [...] > Rebuttal > > For every energy loss, for any inefficiency, for each diminished return > there is but one response: > . > > BUILD THE TOWER HIGHER ! Not quite true, unfortunately ! First, consider a simplification : since your water falls down in a vacuum tube, there is no point in using water, a hydrogen balloon will fall quite as fast, and give you as much energy (except for the weight of the oxygen. By the way, oxygen is *heavier* than air, so anyway your oxygen balloon won't rise. But this is another point) Therefore I suggest the (much simpler) following system, based on the same principle and presumably more efficient (no loss of energy in electrolysis and so on) : There is a huge vertical vacuum tube, and you have a single hydrogen balloon. You drop the balloon at the top of the the tube, and it falls like a stone. At the bottom is a colleague who takes the balloon outside and lets it go : the balloon gently rises in the atmosphere until you can catch it and start the cycle again. Of course, there is a turbine inside the tube and another one outside, so you can produce a lot of energy out of gravity. Now, what's wrong with that ? Your poor colleague, at the bottom, has to pull a balloon from a vacuum (low pressure) tube into the (high pressure) atmosphere. Whatever trick he uses to do that (sophisticated airlock or ...) he will have to provide energy to "compress" the atmosphere. . You could object that you, at the top, can gain energy by letting the atmosphere push the balloon into the tube through a turbine, but since atmospheric pressure is lower, you won't get everything back. What happened to the difference ? Well, it is exactly the (potential) energy that good ol' Archimedes gave your balloon, thanks to the same pressure difference, and that you will retrieve with your turbine in the tube ! Conclusion : as any "perpetual motion" machine, this one will at most give you back the energy you gave it (in fact much less because of friction and all that). This also applies to your original design : to get the gasses in the balloons, you will have at some point to give them the energy you expected them to give you. No free lunch ! I leave it to the physicists to put some numbers and formulas here, but they will find the same result. Now for a more general statement : the laws of physics, as we understand them now, don't allow perpetual motion (not even using a constant gravity or magnetic field, as some people suggested). It is possible that those laws are wrong and someone will come up with a new theory that will allow it (though I personally doubt it). But if you claim you have designed a PMM and you can explain how it works in terms of classical physics (Archimedes' principle, gravity field, permanent magnets and the like), YOU ARE WRONG !! and your place is not is not among the serious people on net.physics :-) *** REPLACE THIS PERPETUAL MOTION MACHINE WITH YOUR CAR ENGINE *** Nic. {ihnp4,seismo,...}!ut-ngp!graner *If Murphy's law can go wrong, it won't*
msb@lsuc.UUCP (Mark Brader) (03/31/85)
merrill@raja.DEC (Rick) describes a scheme for a perpetual motion machine.
(Quote at end.) Of course, it won't work.
The catch is, the operation of electrolyzing (NOT hydrolyzing, that means
something else) the water absorbs not only enough energy for the chemical
reaction but also enough to force away the surrounding atmosphere. After
all, this amounts to lifting the atmosphere against gravity (or compressing
it, if you're operating in a sealed space). When you reverse the reaction,
this is precisely the energy you get back. You used the atmosphere as
a spring, pushing it up and letting it fall back. No gain. Simple, no?
In the machine as described, there is also a severe loss of energy since
the heat from burning the hydrogen back into water is not used.
And to top that, there is a major technical defect. A balloon of
oxygen will NOT rise in the air, because oxygen is NOT lighter than air.
Remember that the density of a gas is proportional to the weight of the
molecules making it up (ideally, anyway, and close enough for this).
Dry air is 78.08% N2 (mol. wt. 28.01), 20.95% O2 (32.00), 1.26% Ar (39.95),
0.05% CO2 (44.01); other components total less than 0.01%. This gives a
weighted average of 29.10, or about 10% lighter than pure O2. If the air
is not dry, it is even lighter since H2O has a molecular weight of 18.02.
However, for purposes of the machine, air doesn't have to be used to float
the balloons; that's just a convenience. We could seal the tower and
substitute a heavier gas such as Ar or CO2 or even Xe (wt. 131.30 -- is this
the densest non-radioactive gas?), or we could even fill it with oil.
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Mark Brader and uw-beaver!utcsri!lsuc!msb
>
> Consider an unfinished tower at the edge of a river. Hydrolysis is performed
> continuously on some water from the river and the subsequent oxygen and
> hydrogen gasses are stored in balloons, which being lighter than air rise
> to the top of the tower where the balloons are burst and a spark ignites the
> gasses which combine into water. The water is permitted to fall through
> a vacuum tube into a turbine which generates twenty percent more electricity
> than is needed to operate the aforementioned operations.
The vacuum tube is, of course, an efficiency frill.