How can a lever make work easier?

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How can a lever make work easier?
Essential Question: Levers & Pulleys Investigation 1- part 1 Levers: Introduction to Levers How can a lever make work easier?

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

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?

Word Bank Lever Lever Arm Fulcrum Load Effort Newton

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?

“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 scientist’s idea of moving the earth, is similar to how you could lift your teacher. Explain.

Essential Question: Levers & Pulleys Investigation 1- part 2 Levers: Lever Experiment A
What happens to the effort needed to lift a load as the position where the effort is applied changes?

Class Data Position of Effort (scale + 0.5 N) Effort (cm)
2.5 cm N 9.9 N 5.0 cm N 5.0 N 10.0 cm 15.0 cm 20.0 cm 25.0 cm

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

“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.

Essential Question: Levers & Pulleys Investigation 1- part 3 Levers: Lever Experiment B
What happens to the effort needed to lift a load as the position of the load changes?

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?

Essential Question: Levers & Pulleys Investigation 2- part 1 More Leverage: Lever Classes
How many ways can you arrange the fulcrum, load, and effort in a lever system?

Word Bank Class-1 lever Class-2 lever Class-3 lever

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

“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.

Essential Question: Levers & Pulleys Investigation 2- part 2 More 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?

Word Bank Diagram

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

“ 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?

What classes of levers can we find in the real world?
Essential Question: Levers & Pulleys Investigation 2- part 3 More Leverage: Real-World Levers What classes of levers can we find in the real world?

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?

“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.

What other levers do we find around us?
Essential Question: Levers & Pulleys Investigation 2- part 4 More Leverage: Lever Pictures What other levers do we find around us?

“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?

How much effort is needed to lift a load in a one-pulley system?
Essential Question: Levers & Pulleys Investigation 3- part 1 Pulleys: 1-Pulley Systems How much effort is needed to lift a load in a one-pulley system? Is it always the same?

Word Bank Pulley Fixed pulley Movable pulley Mechanical advantage

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?

“Pulleys” What is a compound pulley? What is a block and tackle?

How many ways can two pulleys be assembled?
Essential Question: Levers & Pulleys Investigation 3- part 2 Pulleys: 2-Pulley Systems How many ways can two pulleys be assembled? Can two pulleys give more advantage than one pulley?

Word Bank Simple machine

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

“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????

How many pulley systems can you set up?
Essential Question: Levers & Pulleys Investigation 3- part 3 Pulleys: Pulley Game How many pulley systems can you set up?

“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 wedge’s planes affect the sharpness of a blade?

Explain how these items use the wedge!

Essential Question: Levers & Pulleys Investigation 4- part 1 Pulleys at Works: The Effort in Pulley Systems How can we predict the effort needed to lift the load in a pulley system?

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?

“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?

Essential Question: Levers & Pulleys Investigation 4- part 2 Pulleys 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?

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?

“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?

What other lever and pulley systems can you design?
Essential Question: Levers & Pulleys Investigation 4- part 3 Pulleys at Works: Choosing your own Investigation What other lever and pulley systems can you design?

“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?