I did an experiment about two three months back now with five ceramic
doughnut shaped magnets (@15mm diameter, 5mm diameter hole, 2-3 mm thick)
and a large bag of polystyrene beads commonly used for bean bags.
The 5 magnets were held together by having a small steel bolt placed down
the center of the magnets and with a nut on the other end. (I also tried
holding them together...which also worked...)
One of the magnets on the rod was switched, ie
sn, "ns" , sn, sn, sn.
when joined together the magnets were then placed in a big bowl full of
polystyrene beads. When pulled out, the majority of the beads that were
still "Stuck" on the magnet were located at the point where the magnetic
fields were "fighting" each other. To make sure I repeated the experiment
and got a family member who did not see the order the magnets were in, to
show me where she thought the "rouge" magnet was...she got it right every
time...
I have a few ideas on this, but would like to hear from others before I
make my self sound just a tad daft.
Thanks,
Matthew.