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Can anyone figure out what is wrong with this perpetual motion machine? What part of it violates physics? I found it on a website a while ago, and I couldn't figure out what was wrong with it. Thanks, and enjoy!

By the way, here's the website: https://www.lockhaven.edu/~dsimanek/museum/capillar.htm

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  • $\begingroup$ What happens to the capillary action when the tube gets wider? $\endgroup$ – user253751 Jul 30 '18 at 8:41
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    $\begingroup$ Perpetual motion schemes of this type always use capillarity (i.e., surface energy minimization) when it’s convenient but ignore the energy required to exit a capillary, form a new surface, form droplets, etc. $\endgroup$ – Chemomechanics Jul 30 '18 at 14:30
  • $\begingroup$ If the capillary, siphon, and raised container surfaces had such extraordinarily low energy that water spontaneously wicked into them, for example, then it would never drip away as shown in D. Droplet surface energy costs energy that’s not available. $\endgroup$ – Chemomechanics Jul 30 '18 at 14:33
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The answer is quite simple. At the enlarged diameter of the capillary tube, the capillarity is lost/reduced, depending on the diameter. The water will no longer rise into the larger diameter at the top of the capillary tube, and the syphon cannot work without its inlet end being submerged in water.

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Here's some stuff that I found because I was currently researching this question. To the best of our knowledge, perpetual motion machines would violate the first and second laws of thermodynamics, Simanek told Live Science. Simply put, the First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another. A perpetual motion machine would have to produce work without energy input. The Second Law of Thermodynamics states that that an isolated system will move toward a state of disorder. Additionally, the more energy is transformed, the more of it is wasted. A perpetual motion machine would have to have energy that was never wasted and never moved toward a disordered state. If you are still clueless then here's websites that helped me. https://www.livescience.com/55944-perpetual-motion-machines.html [https://www.britannica.com/science/thermodynamics/Isothermal-and-adiabatic-processes#ref510518 Hope this was helpful

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    $\begingroup$ Hi Lance, thanks for your answer. I agree with you that this machine isn't possible due to it violating the laws of thermodynamics. However, I was asking what specific part of the perpetual motion machine was flawed and therefore breaks any physics laws. Does that make sense? $\endgroup$ – F16Falcon Jan 17 '19 at 16:51
  • $\begingroup$ yeah sorry hope you figure it out $\endgroup$ – Lance Kobs Jan 18 '19 at 0:12
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I pump liquid soap out of drums with hoses and electric pumps, so this is easy for me to figure out. The end of the siphon must be lower than the source it is siphoning. You can siphon from A to B just fine, since B is lower than A, but connecting A to C then causes B to be higher, and connecting the two will in fact cause the higher pool to siphon backwards to the bottom one. When I need to get an exact weight on a scale, I use the electric motor to pump extra soap, and once I turn it off it starts to siphon backwards until I close the valve. Picture the sma'll pool being the container I am filling, using the pool at the bottom as a drum, A is an electric motor and the length between A and C has an on off valve in it. Unless the motors forcing up, gravity pushes it back down.

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A, B and C are all part of a single body of water.

  • B will siphon to C through A due to gravity
  • C will rise to A using capillary action

The siphon flow is greater than the capillary flow and so B will empty into C through A until B is below the inlet pipe and the flow will cease.

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