|
Currently on hiatus :-(
 S&W in German/auf DeutschGaia (my fantasy comic) Scarlet (my science fantasy comic) |
|
| Sandra and Woo is supported by our patron Duke. Thank you very much! |
|
![[1128] Perpetual Motion](/comics/2019-11-11-1128-perpetual-motion.png "[1128] Perpetual Motion")
Here they are, the places 31 to 40 of this year’s artwork contest!
- Yuna: They said it was impossible to build a perpetual motion machine! They said it was pseudoscience!
- Yuna: Fools!
- Yuna: HA HA HA HA HA!
- Ye Thuza: Somehow I expected more.
- Yuna: But just imagine! A 93 meter high version would create enough energy to power a Nintendo Switch!
|
Sandra and Woo by Oliver Knörzer is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. See the About page for details.
Privacy Policy | Impressum | © 2008 – 2025 Oliver Knörzer
Sustainable? Yes.
Scale-to-Output Ratio? No,
t209 wrote:
Not to mention that’s most likely under ideal circumstances. What if it’s outside and you get wind/snow/rain?
Then you throw maintenance costs on top of it and all you have is a fun addition to your local science center.
The terrifying thing about this is that you can use a perpetual motion machine to power a slightly bigger perpetual motion machine. She has literally caused the law of thermodynamics to be broken, this child will end the world if we aren’t careful.
It’s slightly more impressive when you consider that, being a perpetual motion machine, it’s creating enough energy to power both a nintendo switch *and* the 93 meter high version of itself.
@ Nitrofluff:
What’s worse is, the larger perpetual motion, by definition, wouldn’t need continual power from the smaller machine; it would only need enough to get started. Meaning that, over time, that perpetual motion machine could start any number of larger perpetual motion machines. The resources to build more machines wouldn’t be an issue either, as with enough time, you could simply create the matter needed out of the energy produced. (Although, there is the problem of what would happen with the anti-matter).
Congrats, Yuna, you seem to have started the solution to any and all energy crises (assuming the people at the science fair take her seriously, and that Yuna doesn’t throw away the machine after the fair is done)
I’m waiting for her to discover that it’s sitting in the breeze from the A/C or heating duct (depending on what season it is) and she’s merely “invented” the world’s most complicated windmill.
Or it’s tapping the temperature differential between the room and Hell (which we’ve already established exists). In which case she’ll be getting a visit shortly from a horned, very annoyed, friend of Larisa’s.
@ It’s_A_Trap:
Don’t sweat the antimatter.
If Yuna can flout energy conservation, violating charge conservation ought to be a snap.
@ It’s_A_Trap:
Yes, but then you have the perennial problem of the person who has everything …
where do you keep it?
And if we’re going to be building something 93m high, I’d like to cover it in solar cells.
Perpetual motion! Forever! BWAHAHAhaha ha ha … ha ……. um.
With low enough friction, a wheel laid flat not on the Equator will spin from Coriolis force and can be tapped for nigh-endless energy from the Earth’s angular momentum.
But relative to Earth’s axis, Yuna’s wheel likely still has an edge closer to the Equator, it’s not aligned straight vertical and North to South, so it could be tapping that energy source.
The infernal look of Yuna’s face on the third panel is priceless!
She gets fifth place after it’s discovered that it’s not truly a perpetual motion machine, it’s just running off dark energy.
Hey, free energy is free engergy.
If games taught me anything then it’s that on the grand scale – even if it’s minuscule – it pays off to just exploit a giant array of free production vs running a costly process.
@ kadaka:
See Futurama for the main problem – eventually you will stop the planet… then you will need to rob another planet of its angular momentum… and to save it you will need to rotate it in another direction…
thats why sun rises in the west in Futurama…
So it’s creating energy now?
Well, why break one law of Thermodinamics when you could break two?
kadaka wrote:
Imagine removing the Sun and Moon and leaving the Earth a closed system. That doesn’t affect your argument and eliminates tidal effects.
Yuna’s wheel will reach a constant angular velocity, either from friction or because power is being drawn from it. In either case, the energy winds up as heat.
But if the Earth continues to slow where is the planet’s angular momentum disappearing to?
If you can’t answer that, your logic fails. Coriolis is only a pseudo-force, the result of your choice of coordinate-system. It spins hurricanes because it changes the direction of motion, but doesn’t cause the motion in the first place. Hurricanes are solar heat engines and don’t tap Earth’s spin.
@ Edda:
If Doom has taught us anything, it’s that tapping Hell Energy always works out.
Looks like Yuna has her mad sciencing down to a, well, science. Love it!
@ MatthewTheLucky:
Its the worst premise ever… What was wrong with original research of teleportation…
Remember she already made a more impressive reverse entropy engine when she set half her room on fire and froze the other half.
How big would it need to be to make time travel possible?
To make the ripples in the pond you first have to throw the rock. May this inspire someone to Do so.
@ Edda: That which is closer to the Equator is moving faster than that farther away. This difference in kinetic energy imparted yields rotation, it is not imaginary. The stored energy of the rotation can be tapped. Where is the planet’s angular momentum going to? To whatever purpose you want the generated energy for!
Once we have room temperature super-conductors and can float wheels on magnetic fields in vacuum, we will have millions of years of available energy, although we will have developed new reactors and other sources far before then.
When the balance of the long-term fate of the universe tips, I guess we’ll know who to blame…
And it goes “PING!”
seeing how that thing spins, i wouldn’t live on the same continent as the 93 meter high version.
@ kadaka:
Even in the absolute most ideal situation, you would at best break even… the coriolis effect wouldn’t work for a machine like this as it needs to go in multiple directions (up, down, forward, and backward). If anything it would slow it down… you would need a 100% perfect vacuum (which even space isn’t) absolutely 0 energy loss (which is also impossible), and then give it an initial source of energy. Only then do you have a CHANCE at a perpetual motion machine that generates 0 power and spins forever because magnetic fields still have energy loss, same with superconductors… As soon as you start tapping into the machine for power, there goes your rotational energy for the machine and eventually it stops… which at that point it will generate as much energy as it used to get it going to start, therefore breaking even.
@ kadaka:
Have you ever taken physics? Angular momentum is conserved and, if the Earth is a closed system, there’s is no way of changing the total quantity. When a bit of the sea floor off Japan collapsed and caused the tsunami which wrecked Fukashima, the Earth’s radius of gyration decreased slightly and the world’s rotation increased. Days became a fraction of a second shorter. But the increase in the world’s rotational kinetic energy came from the decrease in potential energy of the depressed seabed.
Throughout the entire process, the Earth’s angular momentum stayed the same.
Coriolis force is no more real than centrifugal force. Both are simply inertia viewed from a rotating frame. Air moving away from the equator tries to keep its eastward velocity even as the ground’s motion decreases. It only appears that there’s a sideways force. No work is being done.
You cannot extract energy from a rotating body unless it’s coupled to something else. A flywheel can be connected to a generator (producing power and, ultimately, heat) or simply slow from friction in its bearings (producing neat). Generator and bearings are both fixed to the Earth and the Earth absorbs the angular momentum.
Now, the Earth is coupled to the Moon gravitationally. The sea level goes up and down and tidal motors can produce useful work indefinitely (on a human scale). But you need that external coupling. Your plan won’t work. Period!
Fortunately, Yuna’s machine “works” on an entirely different principle. Overbalance wheels have been well studied. They don’t work either, but for reasons having nothing to do with the world’s rotation.
Actually there are multiple good ways to extract free energy.
The classic geo dynamo uses the slip between the core of the Earth and its surface and extracts power from the magnetic field that actually moves (very slowly) relative to the surface. I’ve seen one such educational generator made before ww2 (out of wood, copper and lots of enamel wire) and we had to use a charge pump on the output to dimly light up a single red led once every few seconds. But build it around the equator and you can get as much rotational energy out of the planet as you want.
The second way -first described by Tesla- captures the brake radiation (light) of high energy particles reaching the surface from space. Thanks to our magnetic field and athmosphere, not much gets down to the surface. Tesla had a great idea on how to disable this shielding and get all that nice power. Then he realized it’s bad for organic life. Like his unshielded Roentgen tube power amplifier. (works great for audio or to control your electric car, just burns you, the Tesla tower could utilize both for power harvesting and directed transmission through the ionized atmosphere, which would be very bad for the planet’s biosphere)
The third and most usable way uses a tuned circuit radio receiver to extract power from current day telecommunication signals. Wireless charging also uses this technology, but instead of stealing wifi or mobile power, it has its own radio transmitter on an unused frequency. 5G mobile is especially good as it has electronically formed beams, so it’s possible to step between the tower and a high bandwidth download’s target device to steal most of the power. (any water based living creature could also do this accidentally)
None of them are perpetual motion power sources, just nice ways to get a few watts of power freely from the air. Mostly just enough to run a tiny device for data collection and such. I really hope nobody wants to scale these up.
There’s actually a whole class (multiple classes, probably) of “motors” that are almost like Yuna’s device. An electrostatic motor can be powered off of the potential difference of something like a hundred feet of altitude (lift one wire high in the air, connect the other to ground, and plug in your motor.) They spin impressively fast with no obvious energy input, but have very little torque or power output.
(obviously not “perpetual” – just powered by the same weather/atmospheric things that can produce thunderstorms under the right conditions. ie Solar Energy, eventually.)
Welp, Yuna’s found a way to create energy from nothing – may god bless their souls for whatever’s gonna happen next.
@ Edda:
“Have you ever taken physics?”
That was part of my BA Physics degree, yes.
“You cannot extract energy from a rotating body unless it’s coupled to something else.”
When the ring is magnetically levitated and rotating, it is simple to extract energy by the ring having a construction that disturbs an applied magnetic field. This is a common feature in brushless motor and generator design.
@ kadaka:
Then you’re coupled to the source of the fixed magnetic field.
With a tabletop device, every watt you extract comes from the motion of the wheel, so it soon runs down.
Granted, there’s a heck of a lot of KE in the Earth’s spin, but where can you ‘anchor’ a field-source which doesn’t go ’round with the planet?
@ guest:
Yes, you could extract energy as the North pole shifts. Can you link to anything which shows it’s actually been done?
@ Bill:
My college had an electrostatic motor running in the lobby outside a lecture hall. I’d forgotten. Nice toy and not many people are aware of it, so Yuna might actually win the contest.
Free energy devices are fun. Not from a physics perspective, of course, there are just two possiblities: You either steal someone’s power (from a wireless signal or something) or you use an unusual (and typically inefficient) source of power.
Psychologically, though, they tend to play on greed and/or deception. Ever noticed that no one calls devices that actually produce a reasonable amount of usable energy “free energy” devices? I mean, photovoltaic cells produce “free” energy, right? But everyone knows you have to buy and maintain those cells so you’re basically paying to buy a power plant. So it’s not free.
But if you get a cool device that produces energy by some method most people won’t identify, you tell them it’s magical free energy – you only have to buy the device. Or you even tell them it’s a perpetuum mobile. Or some such nonsense.
Now if you actually could break the rules – create energy or change total momentum/angular momentum or something like that…well, that would be interesting. And scary. But if it could be done, it wouldn’t just be something useless like Yuna’s wheel, it would be on a cosmic scale.
It’s probably not really perpetual motion, just “will run long enough for the science fair to end” motion
@ Edda:
“Yes, you could extract energy as the North pole shifts. Can you link to anything which shows it’s actually been done?”
First you need one of these devices:
https://www.geomag.nrcan.gc.ca/lab/vm/inductor-en.php
Much earlier variants:
http://physics.kenyon.edu/EarlyApparatus/Electricity/Earth_Inductor_or_Delzennes_Circle/Earth_Inductor_or_Delzennes_Circle.html
Then align it to generate the maximal output and then let it stop and measure or collect the small amount of power generated by the movement of the magnetic field relative to the surface.
There was a slightly larger scale experiment done by NASA, that failed due to overcurrent in the main wire due to a construction problem:
https://www-istp.gsfc.nasa.gov/Education/wtether.html
This one used the difference between the speed of the planet’s magnetic field and the orbiting shuttle, which was far greater. The reverse effect could in theory be used as a way of orbital propulsion.
The operation of the basic generator could be tought as taking power from the small movement of a compass needle in a completly stationary compass due to small variations in the direction of the magnetic poles. The idea is that while the poles move relatively slowly, they vibrate slightly at a relatively higher frequency and this movement could be used to generate tiny amounts of energy:
https://www.ngdc.noaa.gov/geomag/GeomagneticPoles.shtml
Also there is the effect of solar plasma on the magnetic field:
https://www.nasa.gov/feature/goddard/2019/in-solar-system-s-symphony-earth-s-magnetic-field-drops-the-beat
@ guest:
Thanks. I didn’t see anything about the magnitude of the daily variations of the poles, but I’ll keep looking.
Any energy harvested by the Shuttle experiment would come from the motion of the craft itself. Continued use would drop it back into atmosphere. And, as the article notes, it could be used to raise the orbit if power (solar?) was supplied. David Brin used the idea in an SF story.
Speaking of SF, Murray Leinster used “landing grids” to lift and land spacecraft. Huge latticework structures which generated some sort of electromagnetic force field. They also ‘tapped the ionosphere for power’, stealing the energy which would normally be ‘wasted’ in the aurora. So colonized worlds didn’t need atomic power or fossil fuels. I wish we knew how to do that. Someone earlier in this thread claimed Tesla knew how but offered no evidence.
Anyway, the next strip is up now. I was just checking back. It’s no wonder Ye Thuza chews her nails whenever Yuna experiments!
@ It’s_A_Trap: Only if the machines produce more energy during their usable lifespan than is required to build them. All renewable energy sources have the same problem. The energy is ‘free’ and the supply is virtually infinite, but it’s not practical to capitalize on this because the margins of return is so slim.