Magnetism

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Magnetism
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What is Magnetism?

• Magnetism is the attraction of a magnet to
  another object.

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What are Magnetic Poles?

• Magnets have two ends, called magnetic poles.
• Magnetism is strongest at the poles of a magnet.

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Magnetic Poles

• Magnetic poles that are alike repel each other.
• North repels North
• South repels South
• Poles that are not alike attract each other
• North attracts South
• South attracts North

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What is a Magnetic Field?

• The magnetic force exerted in the region around
  the magnet is the magnetic field.
• This allows magnets to interact without touching.

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What are Magnetic Field Lines?

• Magnetic Field Lines spread out from one pole,
  curve around the magnet, and return to the other
  pole.

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What do atoms have to do with it?

• All atoms have magnetic fields because of the
  charged particles inside.
• Most atoms magnetic fields point in random
  directions, so they all cancel each other out.

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What do atoms have to do with it?

• In magnetized material, all or most of the
  magnetic fields are arranged in the same
  direction.
• A material that keeps its magnetism is called a
  permanent magnet.

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What do Electric Currentshave to do with Magnets?

• An electric current produces a magnetic field.
• The direction of the current determines the
  direction of the magnetic field.

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What are the magnetic properties of the Earth?

• The Earth has an immense magnetic field around it
  called the magnetosphere.

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What is an Electromagnet

• An Electromagnet is a strong magnet that can be
  turned on and off.
• It consists of a current-carrying wire wrapped
  around an iron core.

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Characteristics of Electromagnets

• Strength depends on the number of coils and the
  size of the iron core.
• The greater the number of turns the coil has the
  stronger the magnet will be.
• The closer the coils are the stronger the magnet
  will be.

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Motors and Generators

• Electric Motor a device that changes electric
  current into mechanical energy.
• Generator a device that changes mechanical
  energy into electrical current.