Force, Energy

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Force, Energy Communication

• Lesson 9
• Bits and Bobs lesson

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Lesson Objectives

• Appreciate the factors affecting the speed of an
  electric motor
• To understand the different ways of carrying a
  current
• To be able to define voltage.

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The electric motor

• The important parts of an electric motor are
• A coil of wire which becomes an ____________ when
  current passes through it.

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The electric motor

• Two permanent magnets with opposite poles facing,
  to make a strong _______ ______ .

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The electric motor

• Two brushes that touch onto the _________ of the
  coil.

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How the motor works
Arrange these sentences into the correct order.
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How the motor works
Arrange these sentences into the correct order.

• The force on this side is downwards
• This pair of forces makes the motor spin round.
• This is how the forces of the coil make the motor
  turn.
• On the other side of the coil, the current is
  passing the other way, from back to front.
• The force on this side is upwards.
• On one side of the coil, the current is passing
  from front to back.

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How the motor works

• This is how the forces of the coil make the motor
  turn.

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How the motor works

• This is how the forces of the coil make the motor
  turn.
• On one side of the coil, the current is passing
  from front to back.

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How the motor works

• This is how the forces of the coil make the motor
  turn.
• On one side of the coil, the current is passing
  from front to back.
• The force on this side is upwards.

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How the motor works

• This is how the forces of the coil make the motor
  turn.
• On one side of the coil, the current is passing
  from front to back.
• The force on this side is upwards.
• On the other side of the coil, the current is
  passing the other way, from back to front.

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How the motor works

• This is how the forces of the coil make the motor
  turn.
• On one side of the coil, the current is passing
  from front to back.
• The force on this side is upwards.
• On the other side of the coil, the current is
  passing the other way, from back to front.
• The force on this side is downwards

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How the motor works

• This is how the forces of the coil make the motor
  turn.
• On one side of the coil, the current is passing
  from front to back.
• The force on this side is upwards.
• On the other side of the coil, the current is
  passing the other way, from back to front.
• The force on this side is downwards
• This pair of forces makes the motor spin round.

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Electric current

• In a wire the current is caused by a flow of
  negative electrons.
• However not all current is carried by electrons!

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Come round the front bench!

• Electrolysis of copper sulphate!

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Electric current

• In an ionic liquid the current can be carried by
  the charged ions.
• In copper sulphate the positively charged Cu ions
  carry the charge the negative electrode.
• The negatively charged sulphate ions carry the
  charge to the positive electrode.

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Electrolysis is the exception to the rule that
current is carried by the negatively charged
electrons!
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Defining the volt! This is HIGHER paper only!

• Voltage is a measure of how much ENERGY each unit
  of charge has.

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Defining the volt! This is HIGHER paper only!

• Energy is measured in JOULES.

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Defining the volt! This is HIGHER paper only!

• Energy is measured in JOULES.
• Charge is measured in COULOMBS

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Defining the volt! This is HIGHER paper only!

• Energy is measured in JOULES.
• Charge is measured in COULOMBS
• So 1 volt 1 joule per coulomb!

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Lesson Objectives

• Appreciate the factors affecting the speed of an
  electric motor
• To understand the different ways of carrying a
  current
• To be able to define voltage.