the polarity of the electromagnet

the polarity of the electromagnet
Same poles repel, unlike poles attract. Whether he is an electromagnet or permanent magnet, is the same.
 Experimental material is actually very good looking.
Enameled wire, scrap motor cube magnets inside, which has the size of the motor.
Iron, nails can be used instead.
Batteries are everywhere.
As for the argument is not the same as the solenoid coil turns to change what you put on it.
Changing only the winding direction of the coil of the electromagnet pole change; only change the connection mode of the battery current direction is changed, the electromagnet poles changed.