How do you determine where the north and south poles are of a magnet in a toy without destroying the toy?

The whole thing is that a toy has a magnet in it and you want to find the north and south poles without ruining the toy.How do you determine where the north and south poles are of a magnet in a toy without destroying the toy?The procedure you would follow depends on how the magnet is constructed. If it is a disk with a central hole, it may be magnetized with one pole on the outer edge and the other pole on the inner edge, like a loudspeaker magnet. Or one side of the disk could be one pole and the other side the other pole. If it is a horseshoe shaped magnet, the poles will be on the two ends, as if a bar magnet had been bent into a horseshoe shape. Of course a bar magnet would be the simplest configuration with the two poles on opposite ends of the bar. There are many other possible configurations. The bottom line is the toy designer may have designed the magnet and its magnetic circuit to minimize any external magnetic field. This can make it very difficult to “find” the magnetic poles.



Exploring the external magnetic field with a small pocket compass may give some insight as to where the poles are. The compass needle will align itself parallel to the external magnetic field lines if they are strong enough. These field lines always begin and end on opposite magnetic poles. By moving the compass around the toy you can make a sketch of the field lines and thereby locate the poles.



Finely divided iron filings, carefully sprinkled on a piece of paper held over the toy, will accomplish the same thing, but that can be very messy and it is not very sensitive unless the magnet is very strong, which is unlikely in a toy.



A sensitive analog Hall Effect probe is probably the easiest way to find the poles. These probes are readily available for a few dollars from electronics distributors such as Newark, Allied, Jameco, DigiKey, etc. They do require a low voltage DC external power supply, a current limiting resistor, and a sensitive voltmeter to operate, so if such things are beyond your means a small pocket compass is probably your best tool.How do you determine where the north and south poles are of a magnet in a toy without destroying the toy?By taking a compass and placing it as close to the magnet in the toy as possible. However the compass points, that is the alignment of the magnetic poles in the toy.How do you determine where the north and south poles are of a magnet in a toy without destroying the toy?Magnetic poles are not tiny points; they are distributed thruout the toy. A compas can tell you which end is which. You can get a better picture of the magnetic field by placing a sheet of paper of the toy and sprinkling iron filings on the paper.