Almost perpetual motion?

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Summary:

Toys or devices that use fundamental atmospheric, gravitational, or electromagnetic forces to run
Perpetual motion is fundamentally impossible. But almost perpetual motion is possible.
The list of toys or devices designed to run for a very long time is short: crookes radiometer (photons, cheap), the drinking bird (heat engine, cheap), the Atmos clock (temperature, expensive), Beverly Clock (temperature, unique), Oxford Electric Bell (battery, unique), and, of course, the only really long term object, the clock of the long now (human interference, unique).
Nothing runs on magnetic flux,as far as I know. Of electrostatics, only the Oxford Bell, which depends on a physical battery, not a natural, universally accessible power source.
Photons, of course, if linked to a battery, in a sunny place. Or wind, or tides, or geothermal. Or satellites.
I'm specifically looking for real objects at the "toy" scale, or ideas that could be made as toys.
 

Answers and Replies

  • #2
DaveC426913
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You're got two very different categories there.

The first category is of devices that are closed: they have a fixed input of energy that they use very judiciously.
The second is of devices that are open: they rely on "free" sources of ambient energy such as sunlight, wind or tides.

That covers a pretty broad range.
 
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  • #3
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Thanks for your reply. Aren't all systems, ultimately, closed, and that's why perpetual motion is impossible? But I agree. From a toy's point of view, or cool physics, relying on a battery is not very interesting, even though since 1840. In its favor, that is 179 years, so it gets huge points just for existing.
Sunlight, wind or tides are possible sources, but I think only sunlight, in crookes radiometer, exists as a toy-like device. And, because it doesn't store energy in a battery, it demonstrates its perpetual motion defect--doesn't work when the sun don't shine.
The drinking bird, given a very large volume of water and the right atmospherics, would run for a very long time. As would all the clocks, but they are unique or extremely expensive.
Can't we imagine a simple, cheap device that runs on available, if minute, energy fluxes?
 
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Soil lamp is an example of something that would run for a long time, but not toy-like, or elegant.
 
  • #5
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I'd be delighted by a self-contained object, in my house, that would run for my lifetime.
 
  • #6
anorlunda
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Could you make a simple toy-like seismometer? It might pick up wiggles as you walk around the house.

I have a solar powered watch that gets enough light indoors to run indefinitely.

How about a barometer or a thermometer?
 
  • #7
DaveC426913
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Solar-powered calculators are common.
 
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anorlunda
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I got it. Solar powered flowers, or similar toys are sold in the dollar store. They jiggle in a cute way.

245725
 
  • #9
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A vat of colored superfluids set on a coffee table in the latitudes of the USA. Swirling vortices should keep spinning until the Earth itself stops.
Perpetual lava lamp, how 1970's.
 
  • #10
anorlunda
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A vat of colored superfluids set on a coffee table in the latitudes of the USA. Swirling vortices should keep spinning until the Earth itself stops.
Perpetual lava lamp, how 1970's.
I really like that. It would be very cool. But are there any room temperature superfluids?
 
  • #11
DaveC426913
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It would be kind of boring as a conversation piece. It would take 24 hours to make one rotation.
 
  • #12
Perpetual motion is possible in vacuum (e.g space) under the presence of only one field and of course we give the object some momentum.
 
  • #13
DaveC426913
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Perpetual motion is possible in vacuum (e.g space) under the presence of only one field and of course we give the object some momentum.
By "only one field" you posit an ideal (physically-impossible) scenario, free of real-world effects.

Even Wiki won't let you get away with that:

"...the motions and rotations of celestial bodies such as planets may appear perpetual, but are actually subject to many processes that slowly dissipate their kinetic energy, such as solar wind, interstellar medium resistance, gravitational radiation and thermal radiation, so they will not keep moving forever ..."
- https://en.wikipedia.org/wiki/Perpetual_motion
 
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davenn
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Perpetual motion is possible in vacuum (e.g space) under the presence of only one field and of course we give the object some momentum.

good try, but you wont succeed
 
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sophiecentaur
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