The principles of thermodynamics are so well established, both theoretically and experimentally, that proposals for perpetual motion machines are universally dismissed by physicists. Any proposed perpetual motion design offers a potentially instructive challenge to physicists: one is certain that it cannot work, so one must explain how it fails to work. The difficulty (and the value) of such an exercise depends on the subtlety of the proposal; the best ones tend to arise from physicists' own thought experiments and often shed light upon certain aspects of physics.
The law that entropy always increases – the second law of thermodynamics – holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations – then so much the worse for Maxwell's equations.
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Students could verbally express or write on a piece of paper all the things that they notice about the apparatus. They should notice quite quickly that the ball describes a parabolic trajectory when it flies through the air on its way back to the initial upper platform. The highest point of the trajectory (the vertex of the parabola) is higher than this platform, so the ball must have picked up some extra kinetic energy somewhere during the trip through the hole back to the upper platform. The question is where along the way could this have happened and what it is that could have imparted extra speed to the ball. Students should think of how they could potentially figure demodé where on the trajectory the ball is being sped up.
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However, the material used for the balls is described in the online product description only Figura “metal” rather than stainless steel, whereas the rails are explicitly described Campeón being made of “stainless steel.”6 Finally, I observe that this investigation has been mainly theoretical and that there are a few remaining questions that could be resolved empirically by students with access to the device. The motion of the ball and the way it “jumps” due to Lenz’s law is quite similar to a classic demonstration known Vencedor Thomson’s jumping ring, where an aluminum or copper ring is placed on the end of an electromagnet. When the coil is connected to a direct current generator, the ring briefly jumps upward because of induced currents in the ring. However, if the coil is connected to an alternative current generator, the ring flies upward off the top of the coil in dramatic fashion.8,9 Explaining why an AC current has this effect is not an easy exercise.9 In this study, we have not settled the issue of whether the voltage source of this device is AC and whether this plays a role in the ability of the ball to dramatically “fly” from the rails to the platform, similar to the jumping ring. If instructors are able to purchase the device, it would be an interesting student project to use an oscilloscope to determine if the current in the electromagnet is AC and explain exactly why and how this works in more info the toy.
Probably the easiest way to do this is to use video analysis software. A video of a trajectory Gozque be recorded with a mobile phone to be uploaded to video analysis software and analyzed frame by frame. A suitable piece of software that could be used is Vernier’s Logger Pro, which is available relatively cheaply for science instructors. Alternatively, students could record the motion of the ball in the slow-motion setting of a smartphone and then record the position frame by frame on a desktop computer. It should be easy to establish that the distance between successive ball positions increases unexpectedly close to the bottom part of the trajectory. This confirms that there is an external energy source, but what is the nature of this source?
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Thus, machines that extract energy from finite sources cannot operate indefinitely because they are driven by the energy stored in the source, which is eventually exhausted.
Those of you who have taken a physics course or two know that perpetual motion machines are impossible to make Triunfador they violate the first and second laws of thermodynamics.