1. Power and Energy Technology
Simple Machines
Power and Energy Technology

2. Behavioral Objectives
Students will gain an understanding and be able to identify and use all of the following:
Six Simple Machines
Four classes of levers
Pulleys
Fixed
Movable
Block and Tackle
Wheels and Axles
Gears
Types
Bicycle applet

3. Incline Plane A surface set to an angle to another surface
Same amount of work just over a longer distance
Resistance
Force
Inclined Plane

4. The Wedge
Double incline plane
Pushes two objects apart
Force
Effort

5. The Screw
A screw is a shaft that has a in inclined groove along its surface.
By rotating the screw (applying a torque), the force is applied perpendicular to the groove, thus translating a rotational force into a linear one.
Babylonians developed a "screw" that could elevate water from a low-lying body to a higher one (which later came to be known as Archimedes' screw).

6. Archimedes' screw

7. Wheels and Axles Type of lever that rotates around a center fulcrum.
Force applied to provide rotation on the axle translates into rotation of the wheel.
Force applied to the wheel causes the axle to rotate, which can be used to magnify the force (by, for example, having a rope wind around the axle).

8. The Lever
Consists of a rigid object (bar of some kind) and a fulcrum (Pivot)
There are three classes of lever
Each offer magnification of the force at another point along the rigid object.

9. Load
Fulcrum
First Class Lever
Effort

10. Second Class Lever
Effort
Fulcrum
Load

11. Third Class Lever
Load
Fulcrum
Effort

12. Pulleys
A wheel with a groove along its edge, where a rope or cable can be placed.
principle of applying force over a longer distance
Provides mechanical advantage

13. Fixed Pulley
Offers no mechanical Advantage
Changes direction of force

14. Movable Pulley Block and Tackle
Combination of fixed and a movable pulleys
Can have several pulleys mounted on the fixed and moving axles, further increasing the mechanical advantage.

15. Block and Tackle Pulleys are assembled together to form blocks
Blocks are paired so that one is fixed and one moves with the load
A single rope is threaded, or reeved, through the pulleys to provide mechanical advantage

16. Types of Block and Tackle

17. Gun Tackle

18. Double tackle

19. Gears Are used to change speed, direction and torque Basic gears
Spur Gear
Bevel Gear
Worm Gear
Rack and Pinion

20. Spur Gear Straight-cut gears are the simplest type of gear
Gears can be meshed together correctly only if they are fitted to parallel shafts.

21. Bevel Gear
Creates right angles
Changes direction of movement

22. Worm Gear High torque, low speed gear ratio
Can create continuous motion

23. Rack and Pinion Toothed bar or rod.
Torque can be converted to linear force by meshing a rack with a pinion: the pinion turns; the rack moves in a straight line

24. Gear Ratios http://illuminations.nctm.org/ActivityDetail.a spx?ID=178
Gear up this bicycle for speed or power.