My ever-vigilant Perpetual-Motion-Claims Patrol

A reader writes:

OK so this looks really cool:

Alabama-Based CMR Demos Programmable Magnets That Changes Polarity And Strength On A Whim

As long as they don't violate the laws of physics that is. What do you think, scam or not?


Correlated Magnetics Hoverfield demonstrator

I don't see any reason to think that Correlated Magnetics are doing anything snake-oil-y. They've just got a way of making single magnets which contain multiple differently magnetised regions.

Take the above "Hoverfield" demonstration unit gizmo, for instance...

...which you can buy for a hundred bucks if you like.

Clear acrylic and magnets doing odd things do indeed instantly start some red flags waving among those of us who're accustomed to independent thinkers like Steorn who, as you say, claim to break the laws o' physics but never quite manage to actually do it. But Correlated Magnetics are not in the physical-law-breaking business. You can make a less elegant contraption that does the same thing all of their products do, at home.

Take the "Hoverfield" thing, for instance. To make your own ugly version, all you need is a couple of large relatively weak magnets, plain ferrites, for instance, and two or more small strong rare-earth magnets.

Now glue the rare-earth magnets onto the faces of the ferrite magnets so that when the ferrites are facing and attracting each other, the rare-earth magnets are facing and repelling. The large ferrite magnets have a big, weak field; the small rare-earth magnets have a little, strong one. So the ferrites attract until they're close enough that the stronger but smaller repulsive force of the rare-earth magnets equals the attractive force of the ferrites, and provided your contraption prevents the magnets from slipping sideways and ruining the demonstration, it'll oscillate to stability with the magnets close, but not touching.

Correlated Magnetics can make a magnet array that does this, but looks like an ordinary single magnet. They produce various other one-piece arrays too. "Coded" magnets that have matching pseudo-random pole patterns so they lock together very strongly but only in one orientation, for instance, and other patterns that reduce the size of the field but strengthen its holding force. (This is also how rubber fridge magnets work - rub a couple of them over each other and you can easily feel the "ridges" of polarisation that make the weak magnetic material able to actually stick to a fridge.) Correlated Magnetics have a few other such creations.

Calling these magnets "programmable" is I think a bit of marketing puffery, since they've got nothing to do with true programmable matter. If these things are really "programmable", then so are those big Edmund-Scientific-type junk-fishing magnets that you can "turn off" with a handle (which moves the magnet inside away from the external field-concentrating pole piece that the junk sticks to).

There's no perpetual motion claims here, though. leave your pitchforks stuck in the haystack, and your torches unlit.

Psycho Science is a... sort of... regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

6 Responses to “My ever-vigilant Perpetual-Motion-Claims Patrol”

  1. MikeLip Says:

    That's kind of cute and a clever pattern, but I'm not sure what they are demonstrating. And I was taken aback by the cost of the thing until I realized they are likely individually made since you could pound those out for at most couple bucks each if you tooled up for it. But yeah, there nothing violating the conventional laws of physics here.

    • dan Says:

      Their main business is bespoke engineered magnet-things for manufacturers; the stuff in their store is just demo units. I presume they were making them anyway and thought "someone'd probably pay for these little things!"

    • TwoHedWlf Says:

      All the best toys violate the laws of physics though.

      ...Or at least appear to, that's what makes them fun.

  2. Anne Says:

    One way they could quasi-legitimately call their magnets "programmable"would be if they had a scheme to install arbitrary specified patterns of magnetization in their magnets. For example they could have a machine that magnetizes tiny cubes in arbitrary directions and intensities, then fuses the cubes together.

    With such a gizmo you could do all kinds of interesting things: for example you could build a cylindrical magnet that produced an extremely Cookstown magnetic field in the cavity, maybe as strong as a Tesla. Then add a few coils and you get a hobby scale MRI machine...

  3. Anne Says:

    In fact it looks like what they have is a two-dimensional version - all you get is a two-dimensional array of axially-magnetized cylinders, but you can choose is the magnetization strength and direction (up or down). And I bet there are limits on size and configuration - anything with assembly forces that are too great is going to be a real challenge (or even spontaneously disassemble itself after being fused).

  4. RichVR Says:

    So where is the ceramic knife review? ;-)

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