At each magnet it is obligatory to eat two poles which are usually called northern and southern. If you have a magnet which poles are not marked, and it is necessary to define its polarity nevertheless (for example if it is an electric motor stator detail. It can be done most without devices.
Instruction
1. The easiest way to define polarity of an unmarked magnet — to use marked. As a rule, the North Pole of a magnet is noted blue paint, southern, respectively — red. As the poles of the same name make a start from each other, and heteronymic are attracted, it is enough to look what pole of your magnet will make a start from the North Pole reference to define where what.
2. In the same purposes it is possible to use a compass which, in fact, represents the magnetic needle which is freely rotating on an axis. Bring the magnet to a compass and look to what its pole the northern end of an arrow will be attracted. It will also be the South Pole of your magnet.
3. If you do not have also a compass, it can be made independently, but the ability to be guided by areas for this purpose will be required. Having carried out on a magnet several times by an iron needle, you will magnetize it. Then, having oiled a needle any, put it on a water surface poured in a saucer. If the saucer rather wide, and nearby is not present strong magnets, then the arrow will point north one of the ends. To define where the North and where the South, it is possible, for example, by the sun — in the northern hemisphere it the most part of year moves on South side of a firmament. After that it is possible to check polarity of your magnet in the same way, as with a usual compass.
4. Lines of a force field are included into the South Pole of a magnet and leave northern, kind of rotating around. The electric charge which appeared in this field will follow the movement of lines. Having filled a little icing sugar in a clean and dry plastic jar, close it and properly shake until powder is electrified and will begin to stick to jar walls. So you receive positively charged dust. Put a magnet on a table so that its poles were in horizontal position. The magnet from the loudspeaker, for example, for this purpose should be put on an edge. Then pour out a little loaded dust in air over a magnet. Motes will twirl along power lines.