Why We Don’t Discuss Perpetual Motion Machines (PMM)

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SUMMARY

This discussion centers on the reasons why Perpetual Motion Machines (PMMs) are not permitted topics on the Physics Forums. PMMs violate the laws of thermodynamics, specifically the conservation of energy and the second law, rendering them scientifically impossible. The forum guidelines explicitly prohibit discussions on PMMs due to their popularity among inventors and the potential for misinformation. Contributors suggest that requiring a working prototype can help differentiate between genuine inventors and frauds, emphasizing the need for a thorough understanding of thermodynamics and energy conservation principles.

PREREQUISITES
  • Understanding of the laws of thermodynamics, particularly the conservation of energy and the second law.
  • Familiarity with Noether's Theorem and its implications for energy conservation.
  • Basic knowledge of mechanical engineering principles related to energy systems.
  • Ability to analyze and critique scientific claims regarding energy devices.
NEXT STEPS
  • Study the principles of thermodynamics, focusing on the Carnot cycle and its efficiency limits.
  • Research Noether's Theorem and its significance in physics, particularly in relation to conservation laws.
  • Learn about the engineering analysis of energy systems, including black box modeling techniques.
  • Examine case studies of historical PMM claims and the scientific responses to them.
USEFUL FOR

This discussion is beneficial for physicists, engineers, inventors, and anyone interested in the scientific principles governing energy conservation and the critique of unconventional energy claims.

  • #31
linkhyrule5 said:
A better version would take the time to really explain why conservation of energy is such a keystone of our theories
berkeman said:
If you're interested in writing a more in-depth Insights article as a "Part 2" to this one,
Tghu Verd said:
Having spoken to a number of 'over unity' zealots, I seriously doubt they would care about all this, or want to take time to understand any of it.

Problem is that some of them really measure over unity, and they just conjecture that they are extracting energy from somewhere. They do not doubt energy conservation, they just thing they have found a new source.

Explanation should address why they are measuring wrong. Most cases, as I said above, is not understanding AC (and surely they will claim to be followers of Tesla :mad:) Some others is pre-storage of energy, either in mechanical or chemical form. Remember all the "water engines" actually burning aluminium. Some other are more subtle, when the "overunity" is one hundred of the circulating energy, then analysis is a lost cause: it can be thermal expansion, gravity doing its job, whatever.
 
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  • #32
Aaand since we are starting to veer into debunking replies, it's probably a good time to tie this thread off.

Good Insights article -- I'm sure its link will get used a lot in the future here in the PF as we lock PMM threads by newbies.

Thanks everyone for a good discussion of the Insights article. :smile:
 
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