How Everything Works
How Everything Works How Everything Works
 

QUESTIONS AND ANSWERS
 
Question 604

How do electromagnets work? — HL, Kurtistown, HI
Whenever an electric current—a current of moving electric charges—flows through a wire, that wire becomes magnetic. This phenomenon is an example of the wonderful interconnectedness of electric and magnetic effects—electricity often produces magnetism and vice versa. Because of its magnetic character, a current carrying wire will exert magnetic forces on another current carrying wire and they are both effectively electromagnets.

A more effective electromagnet uses a coil of wire and a core of very pure iron. Wrapping the wire into a coil gives it specific north and south magnetic poles and adding the iron strengthens those magnetic poles dramatically. Iron is a ferromagnetic material, meaning that it's intrinsically magnetic. All materials contain electrons and an electron has a spinning character that makes it magnetic. But the electron magnetism in most materials cancels completely and only a few materials such as iron retain the magnetism of their electrons. While iron's magnetism is hidden as long as its tiny internal magnets are randomly orientated, its magnetic character becomes obvious when it's inserted in an electromagnet or placed near one. When current flows through the wire coil of the electromagnet, the iron's magnetic poles align with those of the electromagnet and the electromagnet becomes extremely strong.

         

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