View Full Version : OT - nice parlour trick

Ian B
09-01-2012, 08:43 AM
I liked this one for it's mix of hocus-pocus and simplicity:


I guess that most board members can figure out how he's doing it?

As a side note, I wonder how many hits Ebay has since had for "monopole magnet"?


Tony Ennis
09-01-2012, 09:33 AM
I can see the N/S poles on the 'monopole magnet' are not aligned with the faces, but with the edge of the magnet. That being said, I don't know why the coil turns. Unless of course there's something else off-screen.

I was impressed he got the coil balanced as well as he did.

Ian B
09-01-2012, 09:51 AM

I *think* I know how he did it, but before chipping in, let's see what others here think. Bear in mind the guy's profession is - in his own words - a "full time freelance magician and inventor". My thoughts are that this trick owes more to the former profession than the latter.


09-01-2012, 10:40 AM
I dont believe that is a monopole magnet nor do I believe that is the only thing that is 'magnetic' in the setup. There is probably a good reason the magnetic is sticking to that nail and not the other. Pull out both of those nails and prove one is not magnetic (or both.) Based on his information iron nails should not even be needed, show me plastic

Ian B
09-01-2012, 10:52 AM
My thoughts:

Both nails are just plain old nails, the magnet would have stuck to either one.
I think that the only magnet in view (his magical monopole magnet) is the only one there is, and it's all that's needed.
Yes, hammering plastic nails into a lump of wood would have also been a good trick :)

Carry on...


Tony Ennis
09-01-2012, 10:53 AM
Chances are the block is hollow underneath and there's a 9v battery connected to each nail.

09-01-2012, 11:00 AM
The really astounding trick was the ability to pound two nails into a short piece of 2 X 4 without splitting it.

Black Forest
09-01-2012, 11:05 AM
The really astounding trick was the ability to pound two nails into a short piece of 2 X 4 without splitting it.

I thought the exact same thing. I thought for sure if I did that it would split. Of course I would use a BFH!

Ian B
09-01-2012, 11:07 AM

Yes, my guess too - I was thinking a couple of 1.5V AA batteries, seeing as how he's only measuring a couple of volts on his meter. He's made one of the simplest DC motors that you can.

The amusement continues by reading the comments sent in on the Youtube site. He even admits that 'any' magnet would work (of course it would), but wasn't the 'monopole magnet' a nice distraction technique? Staggering how many people still believe in perpetual motion and the like.


Grind Hard
09-01-2012, 11:14 AM
My previous boss thought that nitrogen is flammable... after all they put nitrous in race-cars to make them faster.


The magnetic monopole/monopolar magnet stuff doesn't surprise me. Collectively... over my life... People have gotten much dumber.

We are living in stupid-ified times. And it is only going to get worse.

09-01-2012, 11:26 AM
I would have sanded the block before driving the nails....

09-01-2012, 11:51 AM
The magnetic poles are on the edge of the magnet, and the commutator is all in how you clean the enamel from the wire leads. Sanding the plank after the nails are driven disguises the work needed to drill through to get the nails wired to the hidden battery power.

Edited to explain "commutator" in this case is actually just a make-break switch which is why the armature will turn in either direction, and stall.

Tony Ennis
09-01-2012, 11:58 AM
The really astounding trick was the ability to pound two nails into a short piece of 2 X 4 without splitting it.

Blunt them with a file, and it's easy - the nails crush the wood instead of splitting it.

09-01-2012, 12:21 PM
There's a couple of 1.5V cells in the block attached in series with the nail. The coil's leads on the ends have the insulation stripped from one common side. When the ends of the coils connect to the nails you get a magnetic field in the coil which reacts with the permanent magnet's field causing rotation of the coil until the stripped region is no longer in contact with the nails, through inertia the coil continues to rotate until it's in contact again and the process continues. So as others said - about the simplest DC motor you can make, the 'magic' is in burying the batteries in the wood block so they can't be seen (and I kind of like the dremeled notches in the nails).

Mike Amick
09-01-2012, 07:53 PM
when he is showing the supposed mono mag with the compass .. he actually flips it ..
when he is showing the interaction between the mono and the bar magnet .. he
acts like he flips it .. but .. doesn't .. look close.

This doesn't contribute to the validity of anything .. but .. bothers me that he did that.

Don Young
09-01-2012, 10:23 PM
Nothing at all unusual about the demonstrations with the magnets except the disc shaped one is much stronger than the other. Therefore, the strong one always attracts the weak one, just as it would if the weak one was not magnetic at all. Note that he never demonstated that the two magnets would ever repel each other. I have encountered this same situation many times.

There is obviously some current source in the wooden block to run the 'motor' and while it is spinning the current source can be disconnected and the 'motor' will operate as a 'generator' until it slows down. The rocking motion while starting is typical of ECM's (Electrically Commutated Motors), but I do not know exactly how it is being accomplished. I suspect it is done by having only one side of the rotor support wire cleaned of varnish so that the current cuts off and on as it rotates. With enough rotor inertia it could carry itself around the dead side where the current is normally reversed by the commutator.

Edit: I see rkepler beat me to the draw on the commutation method.

09-01-2012, 10:35 PM
Its a rare earth magnet. I have found when they are next to a weak magnet like a compass or a cheap little science kit magnet like in the video the low strength magnet is basically a chunk in steel. The rare earth magnet overwhelms it.

The Artful Bodger
09-01-2012, 10:49 PM
Did I now show how to make a magnet with three poles just recently? Perhaps I should look further into this free energy stuff!

09-02-2012, 01:25 AM
It doesn't need to be commutated in the conventional sense. It's a variation on a homopolar motor. They are the worlds simplest motor.

Ian B
09-02-2012, 03:53 AM
I was wondering what the fuss was about these 'monopolar magnets'. If it's just a magnet with the same pole at both ends, it can't be that difficult to make - just take a couple of, say, 1" diameter x 1/4" thick neodymium disc magnets with the poles on the faces, clean them, add a drop or two of superglue and crunch them together in an alignment jig in a vice. They're strong, they repel well, but the typical forces we can generate in a home shop shouild be able to overwhelm that easily. Once the glue's set, hey presto, a monopole magnet.

Ebay, here I come...


The Artful Bodger
09-02-2012, 04:05 AM
You would still have three poles, though they would be close together. At least thats how they would appear if you did an iron filings flux map but in reality there would still be four poles with two so close it would be very difficult to tell them from one.

Ian B
09-02-2012, 04:56 AM

Yes, there'd be 3 poles - it'd be, for instance, a NSSN magnet. But if it were thin enough, I'm guessing that it would still have the appearance of a magnet with 2 North poles. A nice coat of 'energy-flux guiding' purple paint around the joint, nobody would be the wiser. Again, I can't think of any real use for it, except as a novelty (think coin with 2 heads). However, seeing how many hits the original video has been getting, and the number of people asking where they can buy such a magnet, it struck me that this might just fill a niche in the free energy market. A fool and his money, etc.


09-03-2012, 10:40 AM
The Magnetic field would be expelled from the join and still appear to be a pair of magnets glued together. There is no way to prevent that.

09-03-2012, 10:51 AM
Here is a company that will sell you magnets that are polarized through the diameter:


Disc shaped magnets are a convenient and popular shape. The size of a disc is given by specifying the Diameter x Thickness.
Most discs are magnetized through the thickness, so that there is a North pole on one flat surface, and a South pole on the other. If a disc is magnetized through the diameter (north on one edge and south on the opposite edge), then it will be clearly marked. Discs magnets are the most economical magnet for the most common holding applications.

The fakery unraveled (This is a magic trick, after all)

The disk is a bar magnet. The faces are non-polarized.


The poles are at two points on the edge of the disk.


The sleight of hand!

The evidence!


09-03-2012, 02:14 PM
How the current is turned on and off


The circuit diagram. Dotted line shows mechanical coupling between coil and electrical switch. By placing a volt meter across the switch or the coil you will measure the full voltage of the battery (the switch is open 50% of the time). It can't be ignored that the nail is also magnetized by contact with the magnet.


09-03-2012, 03:37 PM
I was trying to explain to someone the other day that almost all motors are in fact AC, a common brushed DC motor just has a built in mechanical inverter (the commutator).

Genuine DC motors and generators do exist, in fact that's what Faraday first demonstrated.


Homopolar generators have been used to produce very high currents for melting metals in vacuum furnaces.

09-03-2012, 03:51 PM
This is an interesting one, also.

Note the placement of the magnets on the armature.


Lew Hartswick
09-03-2012, 10:43 PM
This is an interesting one, also.

Note the placement of the magnets on the armature.

That is rather cute. Would make a good display for "Science Fair".:-)

09-04-2012, 12:04 AM
Here is an old "simple motor" that uses a magnetically activated reed switch rather than the make-break switch used in the OP's version. It is still an interrupter process.


While researching this I've discovered what should probably be an obvious concept - the spinning coil, being out of balance, is probably doing a fine job of creating a make/break circuit by itself. There may be no need to fuss with cleaning half the enamel from the pigtail - just clear it all off and it will likely run on the principle of serendipity.

09-04-2012, 09:47 AM
I'm curious as to why the nail that the magnet is stuck to has been cleaned off where the magnet touches, and why he chose to put the meter probe on the magnet, and not the nail.

09-04-2012, 12:10 PM
I'm curious as to why the nail that the magnet is stuck to has been cleaned off where the magnet touches, and why he chose to put the meter probe on the magnet, and not the nail.

More sleight of hand. The block he is assembling is not necessarily the block used in the demonstration. He had to cross-drill the demo block to pass wires to the nails, and he cleaned the nails so they would be in contact with the battery leads. Showing the sanding operation after the nails are in place (an illogical order of operations pointed out earlier here) gave a plausible excuse for the bright nails. It also gives him a sure contact for his volt meter.

Probing the magnet was not necessary and I thought it a distraction, but it is anyone's guess why he opted for that bit of showmanship.