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Bad ideas come and go in physics. But there’s one bit of nonsense that is perhaps more persistent than all others: the perpetual motion machine. No working perpetual motion machine has ever been experiment verified. All break the laws of thermodynamics. In fact, we classify based on WHICH law of thermodynamics they break. We have perpetual motion machines of the first kind – they violate energy conservation – they pump more energy out than they need to keep running. This includes most of the historical devices. Then there are machines of the second kind – they’re a bit more subtle in their wrongness because break the second law of thermodynamics – extracting energy by reversing entropy. Many modern “free-energy” devices fall into this category. Now the best modern designs are by you – answers to our recent challenge question, which we’ll get to at the end. But first let’s take a look at examples of what other people came up with – this’ll be a fun little journey through some pretty terrible science.
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Sound Waves from the Beginning of Time
Hosted by Matt O’Dowd
Written by Matt O’Dowd
Graphics by Kurt Ross
Directing by Andrew Kornhaber
Designing a perpetual motion machine has a very long history and became quite the craze from the middle ages through the renaissance. The first well-documented design for a perpetual motion machine was from the 12th century. Bhāskara’s wheel, named after the Indian mathematician, was embedded with tubes of mercury that would flow from back and forth as the wheel turned. Other types of over-balance wheels followed through to the Renaissance and worked on the same principle. There were also designs that employed the magical-seeming lodestones – magnets. For example, this ramp in which a ball is pulled to the top by a magnet before falling through a hole and rolling to the bottom again. Then there are the self-pumping waterwheels or self-blowing windmills.
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