magnets and electromagnets

magnets and electromagnets

1. bar magnets

   • permanent magnets
   • magnets are made from magnetic material.these are metals that can be magnetised or will be attracted to a magnet.most materials are not magnetic,but iron,cobalt,nickel and steel are.
   • attract and repel
     • if you bring 2 magnets together 2 things can happen-attract or repel.

2. magnetic fields

   • magnets create magnetic fields.these cant be seen.they fill the space around a magnet where the magnetic forces work,where they can attract or repel
   • although we cannot see them,we can detect them with iron filings.the tiny pieces of iron line up in a magnetic field.

3. electromagnets

   • when an electric current flows in a wire it creates a magnetic field around the wire.by winding the wire into a coil we can srengthen the magnetic field.electrommagnets are made from coils like this.we can strengthen the electromagnet wrapping the coil around a iron core.-adding more turns to the coil.-increasing the current.
   • magnetic field
     • the magnetic field of an electromagnet is like a bar magnet one however it can change direction
     • unlike bar magnets that are permanent magnets,electromagnets can be turned o and off by closing or opening the switch.

4. electric bells

   • electric bells have an electromagnet.
     • 1)the current flows through the circuit,the electromagnet makes a magnetic field.
       • 2)electromagnet attracts the springly metal arm.
         • 3)the arm hits the gong,which makes a sound.
           • 4)the circuit is broken.the arm is out of position.
             • 5)electromagnet turned off and the springly metal arm moves back.
               • 6) the circuit is complete again.

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