How to determine the polarity of the magnet
Each magnet is required to have two poles, usually called the north and south. If you have a magnet, whose poles are unmarked, and to determine the polarity is still needed (for example, if it is part of the motor stator. This can be done yourself without the help of instruments.
Instruction how to determine the polarity of the magnet
The easiest way to determine the polarity of the magnet unmarked - labeled use. As a rule, the north pole of a magnet with blue paint mark, south, respectively - red. Since like poles repel each other and opposite charges attract each other, it is enough to see what your pole of the magnet will be repelled from the north pole of reference to determine where any.
For the same purpose, you can use a compass, which, in essence, is a magnetic needle, freely rotating on the axis. Bring a magnet to the compass and see to what its pole is attracted northern end of the arrow. This will be the south pole of your magnet.
If you do not, and compass, you can make yourself, but it will require the ability to navigate the terrain. After the magnet on the iron a few times with a needle, you magnetize it. Then, lubricate the needle any butter, put it on the surface of the water, poured into a saucer. If a saucer is wide enough, but not near strong magnets, the arrow indicates one of its ends to the north. To determine where the north and the south where you can, for example, by the sun - in the northern hemisphere it is most of the year moves on the south side of the sky. After that you can check the polarity of the magnet in the same manner as with an ordinary compass.
field lines are part of the south pole of the magnet in and out of the north, as it were gyrating. Electric charge, appeared in this field, will follow the movement of the lines. Pour a little powdered sugar into a clean and dry plastic jar, close it, and how to shake it until the powder does not become charged and begins to stick to the walls of the jar. So you get a positively charged dust. Place the magnet on the table so that the poles were in a horizontal position. The magnet of the speaker, for example, it will have to put on an edge. Then pour a little of the charged dust in the air above the magnet. Dust will twist along the field lines.