Unit F

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Unit F

• Energy and Motion

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Chapter 15

• Electricity and Magnetism

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Lesson 1 What is Static Electricity?
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Electric Charges

• Many of the atoms that make up matter carry tiny
  units of electricity called electric charges.
• There are two kinds of charges positive and
  negative charges.
• Like charges repel or push away each other
• Unlike charges attract or pull toward each other
• Negative charges can move more easily from one
  material to another.

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Buildup and Discharge

• Static Electricity is the buildup of electric
  charges on the surface of an object.
• Electric Discharge is the loss or release of the
  built-up negative charges.
• a. A bolt of lightning is an example of electric
  discharge.

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Lesson 2 What is Electric Current?
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How Charges Move

1. In order for electric charges to be useful, they
   have to flow.
2. An Electric Current is the continuous flow of
   electric charges.

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Conductors and Insulators

• Conductors are materials that allow electricity
  to pass through them easily.
• Examples Metals (copper, aluminum, gold, and
  silver) and water
• Insulators are materials that DO NOT allow
  electricity to pass through them easily.
• a. Examples plastic, rubber, glass, air, and
  wood.

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Circuits and Switches

• An Electric Circuit is the pathway that electric
  current follows.
• Two kinds of Circuits
• Closed Circuits are circuits that are complete
  (No breaks in the path).
• Open Circuits are circuits that are incomplete (A
  break in the path).

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• A Switch is a device that opens or closes a
  circuit.
• When the switch is off the circuit is open (the
  light is off).
• When the switch is on the circuit is closed (the
  light is on)

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Two Types of Circuits

• A Series Circuit is a circuit in which the parts
  are connected so that the electric current passes
  through a single path.
• A Parallel Circuit is a circuit in which the
  parts are connected so that the electric current
  passes through more than one path.
• a. If you remove one part from the circuit,
  current can still flow.

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Electricity in the Home

1. The electric wiring in a house is connected in a
   parallel circuits.
2. If too much current passes through a circuit, the
   wires can overheat.
3. A fuse is a device that opens a circuit by
   melting or breaking.
4. A circuit breaker is a switch that opens when it
   overheats.
5. An electric cell (battery) is a device that
   changes chemical energy into electrical energy.

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Lesson 3 What Is a Magnet?
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Properties of Magnets

• A Magnet is an object that attracts certain
  metals, mainly iron.
• Magnetism is the magnets ability to attract
  materials.
• Two types of magnets
• Permanent Magnets keep their magnetism for a long
  time.
• Temporary Magnets do not keep their magnetism for
  a long time.

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Magnetic Fields

• The Magnetic Field is the space in which the
  force of a magnet can act.
• The force of the magnet is greatest at the
  magnetic poles (ends of the magnet)
• - Unlike poles attract to each other.
• - Like poles repel each other.

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Earth As a Magnet

• The Earth acts like a magnet because the Earths
  center is made mostly of molten iron that
  produces a magnetic field as the Earth spins.
• Two types of poles
• Geographic Poles are the ends of the imaginary
  line around which the earth rotates.
• Magnetic Poles are the ends of the earth where a
  compass needle will point.

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Lesson 4 How Do Electromagnets Work?

• Electricity and Magnetism

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Electromagnets

• An Electromagnet is a strong temporary magnet
  that uses electricity to produce magnetism.
• The electromagnet is created when an electric
  current passes through a wire coiled around an
  iron core.
• Electromagnets are temporary because they can be
  turned off and on.
• Blenders, computer disk drives, and doorbells all
  have electromagnets.

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Motors and Generators

1. A Motor is a device that changes electrical
   energy into energy of motion.
2. A Generator is a device that uses magnetism to
   convert energy of motion into electrical energy.