# Handling Magnetism

The SuperMag bars, like all bar magnets, have two poles, which are called the "north pole" and the "south pole". Since it's not relevant to know which side of your bars is which pole (unless you want to build a compass), we'll call one the "plus pole" (+) and the other one the "minus pole" (-). You can assign them arbitralily to either side of your bars, as long as the plus pole is the same on all bars, i.e., all plus poles must repel each other, all minus poles must repel each other and all plus poles must attract all minus poles.

You may have noticed that when you attach a plus pole to a sphere and then try to attach another plus pole, it gives a little resistance. Also, when two plus poles are connected to a sphere, it's easier to disconnect them again as compared to when it's a plus pole and a minus pole. More generally, bars will stick to a sphere best if the number of plus poles on the sphere is the same as the number of minus poles. This is something you should always watch out for if you want to do a stable construction. Whenever you attach a bar to a sphere and one side gives resistance, use the other side, unless you have a good reason not to.

Sometimes, however, it is advantageous to break that rule. Let's say, for example, you have a sphere which is connected to four bars above it, so there's room below the sphere, and you want to hang a few sphere on to that sphere. If the sphere is attached to two plus poles and two minus poles, other spheres won't stick to it, because the poles cancel each other out. If however, you attach four plus poles to the sphere, the sphere itself becomes a plus pole, and you can attach other spheres to it, as this video demonstrates:

The more plus poles you attach to your sphere, the stronger a plus pole it becomes itself. On the downside, the more plus poles you attach, the less stable the construction becomes. Try attaching as many plus poles as you can to a sphere and see how far you get before it all flies apart.

A very nice application of these insights is the column of spheres.