1. Introduction to
Simple Machines

2. Objectives After completing this section, students will be able to:
1.    Explain why we use machines, and compare and contrast a simple and a compound machine.    
2.    Name the six simple machines, and identify them in use in various common tools.
3.    Recognize and differentiate between the 3 types of levers.
4.    Apply formulas to compute the efficiency and mechanical advantage of pulley and ramps, and levers.
5.    Explain how the use of a machine does not violate the law of conservation of energy.

3. What are they?
Simple machines are machines with few or no moving parts that are used to make work easier

4. Types of Simple Machines
Wedge
Wheel and Axle
Lever
Inclined Plane
Screw
Pulley
Draw and example of each simple machine.

5. The 6 Simple Machines Screw Wedge Inclined Plane Pulley Wheel and Axle
Lever

6. Why Use Simple Machines?
For the mechanical advantage…
Making something easier to do, but it takes a little longer to do it
For example, going up a longer flight of stairs instead of going straight up a ladder

7. Complex Machines
Combining two or more simple machines to work together
Examples:
Car jack combines wedge and screw
Crane or tow truck combines lever and pulley
Wheel barrow combines wheel and axle with a lever

8. Definitions: Energy: Work= Force: Ability to do work Force x Distance
A Push or a Pull

9. Equation to calculate the amount of Work done
Work = Force x Distance
Variables (W) (F) (d)
W = F x d
W = Fd

10. Units for each measurement
Work is measured in Joules (J)
Force is measured in Newtons (N)
Distance is measured in metres (m)
(or the most appropriate unit)
If W = F x d
Then J = N x m (or Nm)

11. Work input and output
Work input is the amount of work done on a machine. (Win)
Input force x input distance
Work output is the amount of work done by a machine. (Wout)
Output force x output distance
Wout = Win
Fout x Dout = Fin x Din
10N x 3m = 2N x 15m
Din
15 m
Dout
3 m
Fin
10 N

12. Mechanical Advantage

13. Lever
Makes lifting weight easier by using a fulcrum to redirect force over a longer distance
Examples: see-saw, dump truck, broom, crane arm, hammer claw, crow bar, fishing pole, screwdriver, bottle opener

14. First Class Lever
Fulcrum is between EF (effort) and RF (load) Effort moves farther than Resistance. Multiplies EF and changes its direction. The mechanical advantage of a lever is the ratio of the length of the lever on the applied force side of the fulcrum to the length of the lever on the resistance force side of the fulcrum.

15. First Class Lever .
Common examples of first-class levers include crowbars, scissors, pliers, tin snips and seesaws.

16. Second Class Lever
RF (load) is between fulcrum and EF Effort moves farther than Resistance. Multiplies EF, but does not change its direction The mechanical advantage of a lever is the ratio of the distance from the applied force to the fulcrum to the distance from the resistance force to the fulcrum.

17. Second Class Lever
Examples of second-class levers include nut crackers, wheel barrows, doors, and bottle openers.

18. Third Class Lever
EF is between fulcrum and RF (load) Does not multiply force. Resistance moves farther than Effort. Multiplies the distance the effort force travels The mechanical advantage of a lever is the ratio of the distance from the applied force to the fulcrum to the distance of the resistance force to the fulcrum.

19. Third Class Lever
Examples of third-class levers include tweezers, arm hammers, and shovels.

20. Inclined Plane
Makes it easier to move objects upward, but you have to go further horizontally
Examples: highway or sidewalk ramp, stairs, inclined conveyor belts, switchback roads or trails

21. Inclined Plane

22. Inclined Plane
The Egyptians used simple machines to build the pyramids. One method was to build a very long incline out of dirt that rose upward to the top of the pyramid very gently. The blocks of stone were placed on large logs (another type of simple machine - the wheel and axle) and pushed slowly up the long, gentle inclined plane to the top of the pyramid.

23. Inclined Planes
An inclined plane is a flat surface that is higher on one end
Inclined planes make the work of moving things easier
A sloping surface, such as a ramp. An inclined plane can be used to alter the effort and distance involved in doing work, such as lifting loads. The trade-off is that an object must be moved a longer distance than if it was lifted straight up, but less force is needed. You can use this machine to move an object to a lower or higher place.  Inclined planes make the work of moving things easier.  You would need less energy and force to move objects with an inclined plane. 

24. Inclined Plane - Mechanical Advantage
The mechanical advantage of an inclined plane is equal to the length of the slope divided by the height of the inclined plane.
While the inclined plane produces a mechanical advantage, it does so by increasing the distance through which the force must move.

25. Wedges Two inclined planes joined back to back.
Wedges are used to split things.

26. Wedge Pushes materials apart, cuts things
Examples: axe, doorstop, chisel, nail, saw, jackhammer, bulldozer, snow plow, horse plow, zipper, scissors, airplane wing, knife, fork, bow of a boat or ship

27. Wedge – Mechanical Advantage
The mechanical advantage of a wedge can be found by dividing the length of either slope (S) by the thickness (T) of the big end. S
As an example, assume that the length of the slope is 10 inches and the thickness is 4 inches. The mechanical advantage is equal to 10/4 or 2 1/2. As with the inclined plane, the mechanical advantage gained by using a wedge requires a corresponding increase in distance. T

28. Screw Turns rotation into lengthwise movement
Takes many twists to go a short distance
Holds things together
Examples: screws, bolts, clamps, jar lids, car jack, spinning stools, spiral staircases

29. Screw
The mechanical advantage of an screw can be calculated by dividing the circumference by the pitch of the screw.
Pitch equals 1/ number of turns per inch.

30. Wheel and Axle
Makes it easy to move things by rolling them, and reducing friction
Examples: car, bicycle, office chair, wheel barrow, shopping cart, hand truck, roller skates

31. WHEEL AND AXEL
The axle is stuck rigidly to a large wheel. Fan blades are attached to the wheel. When the axel turns, the fan blades spin.

32. Wheel and Axel
The mechanical advantage of a wheel and axle is the ratio of the radius of the wheel to the radius of the axle.
In the wheel and axle illustrated above, the radius of the wheel is five times larger than the radius of the axle. Therefore, the mechanical advantage is 5:1 or 5.
The wheel and axle can also increase speed by applying the input force to the axle rather than a wheel. This increase is computed like mechanical advantage. This combination would increase the speed 5 times. 5 1

33. GEARS-Wheel and Axel
Each gear in a series reverses the direction of rotation of the previous gear. The smaller gear will always turn faster than the larger gear.

34. Pulleys Pulley are wheels and axles with a groove around the outside
A pulley needs a rope, chain or belt around the groove to make it do work

35. Pulley
Makes lifting things with a rope easier by redirecting force and the addition of additional pulleys
Examples: flag pole, elevator, sails, fishing nets, clothes lines, cranes, window shades and blinds, rock climbing gear

36. Diagrams of Pulleys Fixed pulley: Movable Pulley:
A fixed pulley changes the direction of a force; however, it does not create a mechanical advantage.
Movable Pulley:
The mechanical advantage of a moveable pulley is equal to the number of ropes that support the moveable pulley.

37. COMBINED PULLEY
The effort needed to lift the load is less than half the weight of the load.
The main disadvantage is it travels a very long distance. 

38. Summary Wedge Wheel and Axle Lever Inclined Plane Screw Pulley
Pushes material apart, cuts
Wheel and Axle
Makes it easy to move things by rolling them, and reducing friction
Lever
Helps lift heavy weights using longer distances
Inclined Plane
Makes it easier to move objects upward; a longer path, but easier lifting
Screw
Turns rotation into lengthwise movement
Pulley
Makes lifting heavy weights easier by redirecting force

39. Rube Goldberg Machines
Rube Goldberg machines are examples of complex machines.
All complex machines are made up of combinations of simple machines.
Rube Goldberg machines are usually a complicated combination of simple machines.
By studying the components of Rube Goldberg machines, we learn more about simple machines

40. Safety Device for Walking on Icy Pavements
When you slip on ice, your foot kicks paddle (A),
lowering finger (B), snapping turtle (C) extends neck
to bite finger, opening ice tongs (D) and dropping pillow (E),
thus allowing you to fall on something soft.

41. Squeeze Orange Juice Rube Goldberg Machine

42. WEB RESOURCES 1. Divinci's Machines 2. Edhead's 3. COSI applet
2.    Edhead's                      
3.    COSI applet                  
4.    How a bicycle works