1. Simple Machines

2. Simple machines help us do work. Machines make work easy.
A Simple Machine?
Simple machines help us do work.
Machines make work easy.

3. So What? Simple machines make work easier
Simple machines either change the amount of force on an object or change the direction of the force
Machines DON’T diminish the amount of work we do—they just make it easier!
Two or more SIMPLE machines make a COMPLEX machine!

4. What is mechanical advantage?
The number of times a machine multiplies the effort or input force.

5. Mechanical Advantage
It is useful to think about a machine in terms of the input force (the force you apply) and the output force (force which is applied to the task).
When a machine takes a small input force and increases the magnitude of the output force, a mechanical advantage has been produced.

6. What is a Simple Machine?
Simple machines have few or no moving parts.
There are 6 kinds of simple machines.

7. What are the 6 kinds of simple machines?
Inclined plane
2. Wedge
3. Screw
Wheel and axle
5. Pulley
6. Lever

8. An Inclined Plane?

9. Actually, an Inclined Plane…
…inclined plane is like a flat board that is higher on one end.
…inclined plane makes work easier.

10. Inclined Plane
An inclined plane is a slanting surface. This is because your effort is spread out over a larger distance. Lifting an object to the same height requires A LOT MORE effort over a shorter distance
It is easier to push an object up an inclined plane than to lift the object the same height

11. Inclined Plane Shorter distance Longer Distance MORE EFFORT
LESS EFFORT

12. Can you think of some other inclined planes?

13. A Wedge?

14. Actually, a wedge… … is two inclined planes pushed together like a V.
…pushes things away from each other.
…split things.

15. Wedge
A wedge has one slanting slide that ends in a sharp edge which can cut things apart.
A wedge is an inclined plane that decreases the force needed to break apart something.

16. Can you think of some other wedges?

17. A Screw(ge)?

18. Actually, a screw…
…is an inclined plane wrapped around a post or cylinder (the inclined plane allows the screw to move itself when rotated).
…holds things together and can make them go up and down.

19. To help you visualize this better…
# of Threads is equal to Length of the inclined plane
Picture from

20. Can you think of some other screws?

21. Wheels and axles?

22. Actually, a wheel and axle…
…is a pole that goes through the wheel which allows the wheel to turn

23. Can you think of some other wheels and axles?

24. Pulleys?

25. Pulleys
A pulley uses wheels and rope to raise, lower or move a load. A pulley is made up 3 parts:
Pulleys make lifting a load easier by changing the direction of your effort force
Pulley
Load
Effort (force)

26. Parts Of A Pulley
Pulley
Effort (force)
Load

27. Types of Pulleys There are different types of pulleys. Single Pulley
Moveable Pulley
One wheel involved
Multiple wheels involved
Doesn’t increase the effort force; changes the direction
Multiplies the force based on number of strings.

28. Can you think of some other pulleys?

29. Lever?

30. Lever Lever Fulcrum Load Effort
A lever is a bar that rests on a pivot. Levers are made up 4 parts:
Levers make it easy to lift things because they magnify our effort
Lever
Fulcrum
Load
Effort

31. Parts of Lever Lever Load Effort Fulcrum The pivot
Bar of stiff material
Load
The mass to move
Effort
Fulcrum
Force of the person
The pivot

32. Class One Lever Class ONE a seesaw
There are 3 major classes of levers Fulcrum is in the middle between the load and the effort
Class ONE
a seesaw

33. Class Two Lever Class TWO a wheelbarrow
There are 3 major classes of levers Class TWO The load is in the middle Fulcrum and effort at opposite ends
Class TWO
a wheelbarrow

34. Class Three Lever Class THREE tweezers, your arm
There are 3 major classes of levers Effort is in the middle between the load and the fulcrum
Class THREE
tweezers, your arm

35. Can you think of some other levers?

36. Resistance: Object that is moved
What is a Lever?
a rigid bar that is free to turn about a fixed point called the fulcrum
Every Lever has three (3) parts:
Effort:
Where force is placed.
Resistance: Object that is moved
Fulcrum
Pivoting Point

37. Efficiency = output work ✕ 100%
Efficiency is the ability of a machine to convert input work to output work. The efficiency of a real machine is always less than 100 percent because of friction.
Efficiency = output work ✕ 100%
input work

38. Calculating Efficiency
Always express the number as a %

39. Friction reduces efficiency by converting some work into heat.
Oil, or another lubricant, can increase efficiency by reducing the number of contact points between surfaces.
Friction reduces efficiency by converting some work into heat.

40. Simple Machines
Simple machines can be put together in different ways to make complex machinery

41. COMPOUND MACHINES
Many familiar compound machines, such as a car, a washing machine, or a clock, are combinations of hundreds or thousands of simple machines. 41

42. Compound Machine Corkscrew
Inclined Plane
Wedge
Screw
Lever
Wheel and Axle

43. Compound Machine Jack
Inclined Plane
Wedge
Screw
Lever

44. A Wedge in a Compound Machine: Stapler
Staples are wedges: they cut through paper because their ends are pointed in a wedge shape.
Simple machines in a stapler:
Wedge
Lever

45. A Wedge in a Compound Machine: Scissors
The cutting edge of scissors is a wedge.
Simple machines in a pair of scissors:
Wedge
Lever

46. What type of machine?
video

47. Vocabulary Simple machine wedge mechanical advantage wheel & axle
lever
Fulcrum
inclined plane
pulley
Screw
wedge
wheel & axle
Output force
Input force
compound machine