Levers

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Levers

• SCI 201

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Driving Questions

• How can a lever make work easier?
• What happens to the effort needed to lift a load
  as the position where the effort is applied
  changes?
• What happens to the effort needed to lift a load
  as the position of the load changes?
• How many ways can you arrange the fulcrum, load,
  and effort in a lever system?
• What classes of levers can we find in the real
  world and how do people use them to make work
  easier?

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How can a lever make work easier?

• A couple of lever demos
• Levers are used to lift things or overcome
  resistance.
• Levers give mechanical advantage by making work
  easier
• A lever arm is a stick or beam, free to pivot
  about a point
• The fulcrum is the point around which the lever
  arm pivots
• 4 parts of a lever lever arm, fulcrum, effort,
  and load

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Inquiry 1 What happens to the effort needed to
lift a load as the position where the effort is
applied changes?

• Can you lift the load using only one finger?
• Does it always take the same amount of effort to
  lift the load?
• Where should you press to lift the load with the
  least force?
• Be more systematic What is the relationship
  between the load and effort that gives a lever
  user the greatest advantage (i.e. makes it
  easiest to lift the load)?

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Inquiry 2 What happens to the effort needed to
lift a load as the position of the load changes?

• What do you think would happen to the effort
  needed to lift the load if
• the scale stayed at one location on the lever?
• the load moved further and further from the
  fulcrum?
• Be systematic Find out if the result is the same
  as moving the location of the effort.

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More About Levers

• How many ways can you arrange the fulcrum, load,
  and effort in a lever system? Classes of levers
• 1, 2, 3
• What classes of levers can we find in the real
  world and how do people use them to make work
  easier?

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Driving Questions

• How can a lever make work easier?
• What happens to the effort needed to lift a load
  as the position where the effort is applied
  changes?
• What happens to the effort needed to lift a load
  as the position of the load changes?
• How many ways can you arrange the fulcrum, load,
  and effort in a lever system?
• What classes of levers can we find in the real
  world and how do people use them to make work
  easier?