twhitehead and I agree on something, and I find that reassuring. We agree that Perpetual Motion Devices violate the fundamental laws of mechanics and so there is nothing more to discuss.
Perpetual motion is one thing, but the name perpetual motion is understood to mean something else. True perpetual motion could be achieved by taking a mass into outer space and giving it a push. If it stayed far enough away from other bodies, it would just continue to move in perpetuity . But since there is no practical application for this, it is discarded as trivial. I believe this is nearly the situation with the spin and orbit of the planets.
No, what folks really mean when they ask about perpetual motion is, "Can you build a device that will not slow down once put into motion that will allow me to accomplish a task with little to no energy?" Well, in essence folks want us to figure out how to overcome friction, heat, electric field loses, ... Well, those things exist and they can only be minimized, but never eliminated. If you want to discuss low friction bearings, maglev technology and stuff like that, I say "fine." But don't waste your time on perpetual motion.
Originally posted by dinosaurusActually most 'perpetual motion' folks want a device that actually produces energy and I think that that was the plan of the original poster in this thread.
No, what folks really mean when they ask about perpetual motion is, "Can you build a device that will not slow down once put into motion that will allow me to accomplish a task with little to no energy?" Well, in essence folks want us to figure out how to overcome friction, heat, electric field loses, ... Well, those things exist and they can only be mi ...[text shortened]... chnology and stuff like that, I say "fine." But don't waste your time on perpetual motion.
Originally posted by twhiteheadok perhaps i should have avoided the term perpetual motion from the start, its misleading but probably a good attention grabber.
Actually most 'perpetual motion' folks want a device that actually produces energy and I think that that was the plan of the original poster in this thread.
yeah, i wasnt looking for perfection, just a useful form of power assistance would be sufficient to please me : )
i just find it hard to accept that it is beyond the wit of modern man,
im sure that there are major leaps in thinking and inventions waiting to be uncovered. look back in time at all of those discoveries which were beyond the grasp of mans thinking, until that eureka moment.
come on guys, we're the science formum, if we cant figure it out......😛
twhitehead,
I agree most folks want even more than I described. I can often be accused of understatement because I prefer it to overstatement. I felt my description would make them appear less the fool.
As for perpetual-motion-free-energy, I suspect the best we might have right now might be a solar power assisted bicycle or something. Anything approaching the contemporary perpetual motion violates physics. You may as well ask us to stop time or suspend gravity at sea level. Sorry.
ive been thinking again (OH NO you might say)...............
Point A: the solar system is not in perpetual motion because the sun is burning fuel right, but what about the atom? does the rotatiing electron burn energy which would ultimately run out? if not, surely it is in perpetual motion?
Point B: If the atom/ electron etc is not in perpetual motion, that means it will expire, does that mean everything as we know it has a shelf life? Presumably therefore perpetual motion is an impossibility.
Point C; Are new atoms etc being created somewhere to replace those that may or may not be expiring?
Originally posted by eamon oNear perpetual motion not only exists but is very common - if we are not talking about eternity but rather shorter timescales. However, as I said before, that is not what most people actually want when they talk about a 'perpetual motion machine.' What they want is a machine which continues its motion even though power is being drawn off it. That violates the fundamental law of conservation of momentum.
ive been thinking again (OH NO you might say)...............
Point A: the solar system is not in perpetual motion because the sun is burning fuel right, but what about the atom? does the rotatiing electron burn energy which would ultimately run out? if not, surely it is in perpetual motion?
Point B: If the atom/ electron etc is not in perpetual motion, ...[text shortened]... C; Are new atoms etc being created somewhere to replace those that may or may not be expiring?
The main reason why large objects do slow down is that it is virtually impossible to isolate them from other bodies - hence friction a direct physical interaction with other bodies. There are other types of interaction too such as magnetic, gravitational etc.
Originally posted by eamon oAnyone care to comment on these notions please?
ive been thinking again (OH NO you might say)...............
Point A: the solar system is not in perpetual motion because the sun is burning fuel right, but what about the atom? does the rotatiing electron burn energy which would ultimately run out? if not, surely it is in perpetual motion?
Point B: If the atom/ electron etc is not in perpetual motion, ...[text shortened]... C; Are new atoms etc being created somewhere to replace those that may or may not be expiring?
Originally posted by eamon oThe supposed motion of an electron around the nucleus of an atom is the realm of quantum physics. I suspect that it does not in-fact orbit the atom but rather has a random location somewhere in the vicinity of the atom - or even an undefined location.
Anyone care to comment on these notions please?
Originally posted by twhiteheadThanks, I have trawled Wikipedia reading about atoms, electrons etc just now. What I was trying to get at was, whether any known motion at all is perpetual. Now I am beginning to believe that there is no such motion, it seems that even atoms are subject to radioactive decay. If this is the case then the whole notion of perpetuity is a nonsense right?
The supposed motion of an electron around the nucleus of an atom is the realm of quantum physics. I suspect that it does not in-fact orbit the atom but rather has a random location somewhere in the vicinity of the atom - or even an undefined location.
Originally posted by eamon oRadioactive decay has nothing to do with perpetual motion.
Thanks, I have trawled Wikipedia reading about atoms, electrons etc just now. What I was trying to get at was, whether any known motion at all is perpetual. Now I am beginning to believe that there is no such motion, it seems that even atoms are subject to radioactive decay. If this is the case then the whole notion of perpetuity is a nonsense right?
We can observe what is known as the background radiation from the big bang. The background radiation is photons that have been traveling without interruption since the big bang. If that isn't perpetual motion then I don't know what is. Obviously the ones we observe are no longer in motion - I guess one can not observe perpetual motion without disturbing the system.
Originally posted by twhiteheadok so the big bang's rbackground radiation is travelling a long time but is it slowing down?
Radioactive decay has nothing to do with perpetual motion.
We can observe what is known as the background radiation from the big bang. The background radiation is photons that have been traveling without interruption since the big bang. If that isn't perpetual motion then I don't know what is. Obviously the ones we observe are no longer in motion - I guess one can not observe perpetual motion without disturbing the system.
I discounted light when thinking about motion. Is lights travel perpetual or does it decay/ run out of steam so to speak?
Originally posted by dinosaurusdo you think that we really understand light yet? weve been measuring it and observing its properties for a long time but do we really know understand it? eg -if i flash a light into the sky how far/ long will it go? (ignoring dispersion)
Light disperses as it propogates and would eventually become unmeasurable. However, Newtonian physics deals with particles and stuff, and I don't think light follows the same rules.
Originally posted by eamon oWell, here is some of what I remember of light as we discussed it in Physics.
do you think that we really understand light yet? weve been measuring it and observing its properties for a long time but do we really know understand it? eg -if i flash a light into the sky how far/ long will it go? (ignoring dispersion)
Light is a form of energy that propagates as a wave. There appear to be two components to this wave and we can effect the light through polarization which has the effect of blocking much of the energy.
There is no reason to think light would not continue to propagate, except for a black hole bending it and swallowing it up. In this way, light appears to have a component that acts like a particle in motion.
One strange element of light is that we can bend it by having it pass through different media with different light impacting densities. I do not recall the scientific name for this sort of density property of matter. But this is why a spoon appears to bend when placed in a glass of water.