Is a Perpetual Motion Machine Really Possible? Part 1

Is Perpetual Motion Possible?

Short answer: No. Central to the notion of a perpetual motion device, is the requirement for a machine to keep running without any additional energy being added to the system. No fuel, no blowing, no prodding – nothing. This being the case, it is inevitable that any machine – no matter how well conceived – will slow down over time. (Due to various forms of friction – regardless of how insignificant they may appear.)

But what about the machines I’ve seen on the internet?

Impressive they are; perpetual they are not. (First law of thermodynamics and all that.) Yes, once set in motion, they do run on and on – presumably forever. But they are not perpetual motion machines.

Why aren’t they?

"There’s no external power source; no one’s blowing on it or prodding it and yet still: round it goes! Round and round and round…"

If you are confused by all this, believe me, you are in good company. This has not been helped by the number of “perpetual motion devices” that are demonstrably merely executive toys – delighting generations with their hidden magnets.

What about the “real” ones?

The real ones (and by that I mean the genuine attempts) do have additional energy continually applied to them in the form of gravitational force. Being subjected to it from the day we are born, we naturally tune it out from our lives – to the point where we forget that it is there at all. But don’t imagine for a minute it isn’t there: as the select few who have experienced weightlessness are all too aware.

Gravity can’t be doing it – It’s force is the same on all parts of the machine!

Yes, that’s true. Every cog, every nut and bolt, every atom of every machine is subjected to the same gravitational force – so surely logic would dictate that forces would just be cancelled out. But think about that physics lesson you had in school. You know: the one about turning moments – the one about levers.

Levers?

With this in mind, think again about the genuine attempts. How their core movement rotates around a central axis. Now look at how the weights move closer to the centre of rotation on one side and further away on the other. In other words: how the turning moment is greater on one side than the other. Different inventors have used different moving weights over the years: Ball bearings or liquid – free to move inside a series of tubes. All of these have been to the same end: to create more leverage on one side of the wheel than on the other – generating rotation.

Bhāskara's wheel

Arguably the most enduring of these, was the work of Indian mathematician, Bhāskara II. In 1150CE he managed to create a wheel which utilised a series of hollow spokes, partially filled with mercury. By partially filling each spoke, the mercury was able to move freely – naturally moving closer to the axle on one side of the wheel than the other (and generating rotation.) Again, not perpetual motion – just very, very clever.

Photo by Pixabay

This diagram shows the principle of Bhāskara's wheel.

Disappointed? Don’t be

So, is it possible to make a perpetual motion machine? Well, no…not really. But please don’t let that put you off. Gravity powered devices are real. That in itself opens up a fascinating area of engineering. An area that, perhaps, you would not have come across had it not been for your intellectual curiosity getting the better of your natural scepticism. You’re my kind of person (I find the area fascinating as well). Now, reactionless drives on the other hand…