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

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

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

3. 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?

5. Word Bank • Lever • Lever Arm • Fulcrum • Load • Effort • Newton

7. 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?

8. “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.

9. 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?

10. 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

11. Word Bank • Two-coordinate graph • Advantage

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

13. “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.

14. 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?

15. 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?

16. 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?

17. Word Bank • Class-1 lever • Class-2 lever • Class-3 lever

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

19. “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.

20. 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?

21. Word Bank • Diagram

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

23. “ 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?

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

25. 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?

26. “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.

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

28. “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?

29. 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?

30. Word Bank • Pulley • Fixed pulley • Movable pulley • Mechanical advantage • Directional advantage

31. 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?

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

33. 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?

34. Word Bank • Simple machine

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

36. “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????

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

38. “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?

39. 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 • Woodpecker’s bill

40. 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?

41. 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?

42. “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?

43. 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?

44. 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?

45. “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?

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

47. “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?