Gravity, Electricity,

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Gravity, Electricity, Magnetism

• S8P5. Students will recognize characteristics of
  gravity, electricity, and magnetism as major
  kinds of forces acting in nature.

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Enduring UnderstandingsStudents will understand
that

• Electric forces arise from the movement of
  electrical charge.
• Magnetic forces arise from the movement of
  electrical charge.
• An electric circuit allows electrons to flow from
  a negative pole to a positive pole.

3

• Series and parallel circuits can be used to
  control the amount of electric energy produced.
• Every object exerts gravitational force dependent
  upon its mass and distance from other objects.

4
Gravity

• The force that attracts all objects toward each
  other.
• Gravity depends on two factors
• Mass of objects
• Distance between objects

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Mass Amount of matter in an object
Weight Force of gravity on an object
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Electricity

• The collection or flow of electrons in the form
  of an electric charge.
• Electrons are a negatively charged particle
  located outside the nucleus of an atom.

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Static Electricity

• Is the charge that stays on an object.
• Unlike charges (,-) attract each other, and like
  charges (,), (-,-) repel each other.

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Materials affect charge movement

• Conductors- a material that allows an electric
  charge to pass through it easily.
• Examples iron, steel, copper, aluminum
• Insulators- a material that does not allow a
  charge to pass through it.
• Examples plastic rubber

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Electric Current

• The steady flow of electricity.
• A current will move along a wire or a
• path called a circuit.
• Circuit means to go around.
• There are two types of circuits
• Series Circuit
• Parallel Circuit

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In which direction does the current flow?

• From the Negative terminal to the Positive
  terminal of a cell.

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Types of Circuits

• Series Circuit is a circuit that has only one
  path for the current.

• Parallel Circuit is a circuit that has more than
  one path for current to travel.

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Short Circuits

• An unintended path connecting one part of a
  circuit with another.

• A short circuit will cause large amounts of
  current to flow in a circuit and overload the
  circuit.
• They are very dangerous.
• The wires on a circuit can melt and then cause a
  fire.

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Magnetism

• A push or pull exerted by a magnet.
• There are two poles.
• North
• South
• If you cut a magnet in half, you do not separate
  one pole from the other. Both pieces will have
  two poles.

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• Opposites attract
• Like poles push away from each other.

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Magnetic Field

• The area surrounding the magnet is the magnetic
  field.
• Where the lines are the closest, the magnetic
  force is the strongest.

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Electricity Magnetism

• Passing a current through a piece of wire causes
  a magnetic field to form around a wire
  (electromagnetism).
• The strength of the magnetic field could be
  greater if you put a piece of copper inside the
  wire. This is called an electromagnet.

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Electromagnets

• Their magnetism can be turned on or off.
• Stopping the flow of electric current through the
  wire coil stops the magnetic field.
• How do we change the strength of the
  electromagnet?

To INCREASE To DECREASE
Increase the strength of the current Decrease the strength of the current
Add more coils of wire Use fewer coils of wire
Increase size of iron core Decrease size of iron core