Electricity and Magnetism

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Electricity Magnetism
Presentation by Jo McArn 4th Grade Bessemer
City Central
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4th Grade Science SCOS Competency Goal 3

• The learner will build an understanding of
  electricity and magnetism.

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Essential Question

• How does electricity and magnetism affect your
  life?

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Sources of Electricity

• Burning of fossil fuels (coal, oil, and natural
  gas).
• Energy of wind (wind power).
• Energy of water (hydroelectric power).
• Energy of the sun (solar power).
• Thermal energy that is naturally produced within
  the Earth (geothermal energy).

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What is static electricity?

• Static electricity is the charge that stays on an
  object.
• Objects become electrically charged when they
  gain or lose negative charges.
• A charge causes an electric field.
• Objects with like charges repel each other.
• Objects with unlike charges attract each other.

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What is an electric current?

• An electric current is a flow of electric charges
  through a path called an electric circuit.
• A material in a circuit can be called a
  conductor, an insulator, or a resistor.
• A series circuit has one path for current.
• A parallel circuit has more than one path for
  current.

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What is a magnet?

• A magnet is an object that attracts certain
  materials, usually made of iron or steel.
• Every magnet has two magnetic poles, north and
  south.
• Magnetic forces are caused by the interaction of
  magnetic forces.
• Earth has a magnetic field that compass needles
  interact with.

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What is an electromagnet?

• Wires carrying an electric current become
  magnets.
• An electromagnet is a core wrapped with wires
  that carry current.
• An electromagnet is magnetic only when there is
  electric current in the wire.
• Generators use electromagnets to produce current
  from motion.
• Motors use electromagnets to produce motion from
  current.

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Everyday Uses for Magnets

• Computers ?Battery
• Telephone ?Generator
• Door bells ?Alarm bell
• Television ?VCR
• Credit card swiping machines
• Compass
• MRI Machines

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Electricity can be dangerous.

• Pull electrical cords from sockets only by their
  plugs.
• Avoid using electric appliances around water.
• Touch electrical appliances and switches with dry
  hands only.
• Do not play around power lines.
• If you are unsure, ask an adult.

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Sources

• Harcourt Science Teachers Edition, Harcourt
  Inc., 2000
• Pictures from Microsoft ClipArt