• Question: why do ellectro magnets work

    Asked by darthvader to Andrew, Ash, Gem, Paige, SJ on 29 Jun 2012.
    • Photo: Paige Brown

      Paige Brown answered on 29 Jun 2012:

      Good question! Electromagnets are devices that create a magnetic field through the application of electricity. When you apply electricity through a metal object, a magnetic field is produced at the same time! You can hardly have one without the other.

      “Mechanically, an electromagnet is pretty simple. It consists of a length of conductive wire, usually copper, wrapped around a piece of metal. Like Frankenstein’s monster, this seems like little more than a loose collection of parts until electricity comes into the picture. But you don’t have to wait for a storm to bring an electromagnet to life. A current is introduced, either from a battery or another source of electricity, and flows through the wire. This creates a magnetic field around the coiled wire, magnetizing the metal as if it were a permanent magnet. Electromagnets are useful because you can turn the magnet on and off by completing or interrupting the circuit, respectively.”

      http://www.howstuffworks.com/electromagnet.htm

    • Photo: SarahJayne Boulton

      SarahJayne Boulton answered on 29 Jun 2012:

      Electromagnets work by exploiting one of the most awesome properties of metals – the fact that electrons can move freely through the solid material – otherwise known as ‘they conduct electricity’.

      You can’t make an electromagnet out of something that doesn’t conduct electricity as it is the way that the electrons move that generate the magnetic field. The best metal to use is soft steel, as it is a very pure form of iron, with lots of free flowing electrons. It’s also best if you bend the steel into a C shape with a small gap between the tow ends (this helps shape the field you generate into it’s strongest form)

      So you take your softsteel and wrap a wire around it. Copper is best because it is ductile (‘can be pulled out into a wire’) and because out of the good ductile metals it has the lowest resistance at room temperature (meaning electrons or ‘a currrent’ of electrons can move easily through the metal without it getting too hot). the number of times you wrap the copper round the steel core is given the name ‘Mu’. the bigger Mu is, the better your magnet will be.

      The current flowing though the wire polarises (lines up) the electrons in the steel core, making one end positive and one end negative. This is a magnetic field. When another object whose electrons move nice and easily moves into this field, the magnetic field causes the ojects electrons to also rearrage in a complementary fashion and the two objects are attracted to each other.

      This is only part of the story and there are exceptions more indepth explanations to how electromagnets work (for eaxmple how not all metals are magnetic), but I hope this helps you see how electrons and electricity fit into the equation!!
      🙂

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