How are refrigerator magnets made?
Examine a refrigerator magnet. It is flexible, feels like rubber, and only one surface is attracted to metals. It doesn’t stick to a stainless steel door unless the stainless has been coated with steel. It’s made of rubber that has been impregnated with ferrite particles and magnetized. Small pieces, each a dipole, are then pressed together under heat to bond them into one thin sheet that can be cut, folded, and bonded to other sheets. Which of the three arrangements shown below would have the properties of a refrigerator magnet as described above?
The top two wouldn’t because both surfaces would act as a magnet. The top right-hand arrangement would be a very weak magnet on both faces because the alternating poles would essentially cancel each other out.
In the third drawing the sheets have been folded and then pressed together so that the poles are at only one surface, so only that surface would act like a magnet. The alternating N and S poles attract steel and stick to it. You can check this idea by taking two refrigerator magnets and holding the magnetic surfaces together, and then try sliding one over the other. You’ll find that they skip as first N and S poles touch each other and attract. Then the like poles try to touch each other but repel, making the magnets skip.