Essential Question: Levers

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Essential Question Levers Pulleys
Investigation 1- part 1Levers Introduction to
Levers

• How can a lever make work easier?

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ENGAGE

• How could you lift your teacher in the air?
• Could you do it with one hand?

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EXPLORE

• Can you lift the load using only one finger?
• Does it always take the same amount of force to
  lift the load?
• Where should you press to lift the load with the
  least force?

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Word Bank

• Lever
• Lever Arm
• Fulcrum
• Load
• Effort
• Newton

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Content/Inquiry

• A lever can make a load easier to lift, it can
  move loads, and it reduces the effort.
• In a lever system the farther from the fulcrum
  the effort is applied, the greater the advantage
  to the lever user.
• Student questions?

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Simple Machines

• Identify 5 or more simple machines that we use
  every day.
• For each simple machine listed above, tell why
  people use the tool?
• Archimedes, the Greek mathematician and
  scientists idea of moving the earth, is similar
  to how you could lift your teacher. Explain.

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Essential Question Levers Pulleys
Investigation 1- part 2Levers Lever Experiment A

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

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Class Data

• Position of Effort (scale 0.5 N)
• Effort (cm)
• 2.5 cm 9.4 N 9.9 N
• 5.0 cm 4.5 N 5.0 N
• 10.0 cm
• 15.0 cm
• 20.0 cm
• 25.0 cm

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Word Bank

• Two-coordinate graph
• Advantage

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Content/Inquiry

• The farther the effort is from the fulcrum, the
  easier it is to lift the load.
• Student questions?

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Class-1 Levers

• What is a mechanical advantage?
• What advantage rule can we state about a class-1
  lever?
• What is the cost of making the work easier?
• Get a tool from the teacher and draw a diagram of
  it. Identify and label on your drawing the
  location of the load, effort, and fulcrum.
  Notice the distance of the load to the fulcrum.

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Essential Question Levers Pulleys
Investigation 1- part 3Levers Lever Experiment B

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

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Content/Inquiry

• The effort needed to lift the load decreases as
  the load gets closer to the fulcrum the effort
  increases as the load gets farther from the
  fulcrum.
• Student questions?

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Essential Question Levers Pulleys
Investigation 2- part 1More Leverage Lever
Classes

• How many ways can you arrange the fulcrum, load,
  and effort in a lever system?

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Word Bank

• Class-1 lever
• Class-2 lever
• Class-3 lever

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Content/Inquiry

• Levers can be set up in three basic ways. They
  are called class 1, class 2, and class 3.
• Student questions?

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The Wheel and Axle

• When you use a wrench to tighten a bolt, are you
  looking for a gain in effort or distance?
• When you use a windlass to raise a bucket from a
  well, what is the gain?
• How do you think the key to a music box works, in
  terms of a wheel and axle?
• How do you think the front wheel and the rear
  wheel of a bicycle are different? Which one is
  the wheel and axle? Explain how a bicycle works.

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Essential Question Levers Pulleys
Investigation 2- part 2More Leverage Lever
Diagrams

• What conventions can be used so we can
  communicate in the same language and have an
  efficient way to record the lever systems we
  build?

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Word Bank

• Diagram

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Content/Inquiry

• A diagram uses a system of symbols and
  conventions to communicate information about
  lever designs.
• Student questions?

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Class-2 Levers

• What is the mechanical advantage of the class-2
  lever?
• What advantage rule can we state about a class-2
  lever?
• What is the load in a bellows?
• How is the bellows like a nutcracker and garlic
  press?

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Essential Question Levers Pulleys
Investigation 2- part 3More Leverage Real-World
Levers

• What classes of levers can we find in the real
  world?

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Content/Inquiry

• Many common tools use levers scissors, pliers,
  bottle openers, hammers, wheelbarrows, and
  brooms, to name a few.
• Effort is reduced as the load moves closer to the
  fulcrum.
• Student questions?

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Class-3 Levers

• What is the mechanical advantage of a class-3
  lever?
• What advantage rule can we state about a class-3
  lever?
• Explain why the catapult is a class-2 lever when
  it is being loaded and a class-3 lever when it is
  hurling a rock.

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Essential Question Levers Pulleys
Investigation 2- part 4More Leverage Lever
Pictures

• What other levers do we find around us?

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The Inclined Plane

• What is the advantage of an inclined plane?
• What is the disadvantage?
• What simple machine is used to make a wheelchair
  ramp?
• How can a plank be used as an inclined plane?
• Are there inclined planes in our school?
• Which trail would be the easiest to hike to get
  to the top of the hill?
• What is the disadvantage if you take the easiest
  route?

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Essential Question Levers Pulleys
Investigation 3- part 1Pulleys 1-Pulley Systems

• How much effort is needed to lift a load in a
  one-pulley system?
• Is it always the same?

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Word Bank

• Pulley
• Fixed pulley
• Movable pulley
• Mechanical advantage
• Directional advantage

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Content/Inquiry

• A single pulley can be set up as a fixed pulley
  or a movable pulley to lift a load.
• Single fixed pulleys change the direction of
  effort. Single movable pulleys reduce the effort
  needed to lift the load.
• Student questions?

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Pulleys

• What is a compound pulley?
• What is a block and tackle?

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Essential Question Levers Pulleys
Investigation 3- part 2Pulleys 2-Pulley Systems

• How many ways can two pulleys be assembled?
• Can two pulleys give more advantage than one
  pulley?

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Word Bank

• Simple machine

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Content/Inquiry

• Two pulleys can provide greater mechanical
  advantage than one when lifting loads.
• Simple machines provide mechanical or other
  advantage.
• Student questions?

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Dear Boss

• Does the poem explain how pulleys really work?
• What kind of pulley system did the bricklayer
  use?
• Relate to poem-do you know?
• What country? Bloody? Sod? Hod?
• Why is this poem humorous????

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Essential Question Levers Pulleys
Investigation 3- part 3Pulleys Pulley Game

• How many pulley systems can you set up?

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The Wedge

• How do they keep the airplane from moving?
• How is a wedge related to an inclined plane?
• What are some of the wedges you have seen in use?
• How does the slope of a wedges planes affect the
  sharpness of a blade?

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Explain how these items use the wedge!

• Nail
• Pin
• Needle
• Chisel
• Ax blade
• Saw blade
• Knife blade
• Scissors blade
• Bow of a ship
• Nose of an airplane
• Woodpeckers bill

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Essential Question Levers Pulleys
Investigation 4- part 1Pulleys at Works The
Effort in Pulley Systems

• How can we predict the effort needed to lift the
  load in a pulley system?

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Content/Inquiry

• The greater the number of ropes supporting the
  load, the less the effort needed to lift the
  load.
• The effort needed to lift a load can be predicted
  from the weight of the load and the number of
  ropes supporting the load.
• Student questions?

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The Work of Pulleys

• Where do you find pulleys in the real world?
• How does a chain hoist work?
• What modern-day machine has replaced pulleys?

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Essential Question Levers Pulleys
Investigation 4- part 2Pulleys at Works
Measuring Distance

• What is the relationship between the mechanical
  advantage and the distance the load and the
  effort move in a pulley system?

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Content/Inquiry

• The benefits gained by using simple machines are
  always balanced by cost. When the benefits
  outweigh the costs, the machine is a useful tool.
• In a lever system, a reduction in effort is
  balanced by the distance over which the effort
  must act.
• Student questions?

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The Screw

• How is a screw a variation of an inclined plane?
• What tool is used to turn the screw into the
  wood?
• What kind of simple machine is the screwdriver?

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Essential Question Levers Pulleys
Investigation 4- part 3Pulleys at Works
Choosing your own Investigation

• What other lever and pulley systems can you
  design?

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Thank you, Mr. Clumpet

• Are there any levers? What types of levers are
  they?
• Are there any pulleys? What types of pulleys are
  they?
• Are there any wheel and axles?
• Are there any inclined planes? What types or
  variations of inclined planes are they?