1. What to do… Open your notes to page 42
Answer the following prompt in the “Think About It”:
Can you think of an example of a time when you used a simple machine?

2. Machines Chapter 21, Section 3
Standards:
Differentiate between the six simple machines.
Determine the amount of force needed to do work using different simple machines.

3. Simple Machines
Simple machines are devices that make work easier by changing the amount or the direction of force.

4. Simple Machines can help by
How Do They Help Us?
Simple Machines can help by
Increasing the force that enables us to lift heavy objects
Changing the direction of the force that enables us to move objects in different directions
Increasing the speed of a force to enable us to move things farther or faster.

5. 1. Inclined Plane
Consists of a plane surface which is tilted or inclined. Using an inclined plane to move a heavy object takes less force than lifting it directly.
Examples include
Ramp for loading and unloading
a switchback road
waterslide
ladder

6. 2. Wedge
Consists of two planes and is usually used to cut or to break things apart.
Wedges move objects by being forced under or between them.
They alter the direction of a force applied to them.
When you push down on a wedge it pushes out on the two planes that it is in between.

7. Examples of Wedges
Log splitter (a wedge used with a sledge hammer to split logs)
Cutting edges of chisels, knives and scissors
Points of nails, needles
Tip of a screw driver
Tines of forks
Door Stops
Axe

8. Consists of an inclined plane wound around a post.
3. Screw
Consists of an inclined plane wound around a post.
Screws can lift things
Examples:
Jack Screw
Piano Stool
nut and bolt

9. 4. Lever
There are three types of levers that are classified according to their three parts:
Fulcrum (pivot point)
Effort Arm
Resistance Arm

10. The Fulcrum is in between the resistance and effort.
First Class Lever
The Fulcrum is in between the resistance and effort.
Effort
Resistance
Fulcrum

11. Examples of a First Class Lever
Car Jack
Crowbar
Hammer Claw (used to pull out nails
Balance for massing and weighing objects
Hedge Trimmers
Pliers

12. Second Class Levers
The resistance is between the fulcrum and the force
Effort
Resistance
Fulcrum

13. Examples of a 2nd Class Lever
Nut Cracker
Garlic Press
Wheelbarrow

14. Third Class Lever
The force is in between the resistance and the fulcrum.
Effort
Resistance
Fulcrum

15. Examples of a 3rd Class Lever
Broom
Tweezers
Catapult
Hockey Stick

16. There are two types of pulleys:
Consists of a grooved wheel (or wheels) that spins on a fixed axis with a rope or chain moving over the wheel.
There are two types of pulleys:
Fixed pulleys
Movable pulleys

17. Fixed Pulleys
Wheel(s) and rope are fixed in place. They make lifting easier by changing a push to a pull.
Examples:
clothesline
flagpole
mini-blinds
sailboats(to raise a sail)

18. Movable Pulleys
Wheel(s) and rope are attached to and move with the resistance. They make work easier by changing force.
Example: Block and Tackle
It makes work easier by changing the direction of force and decreasing the force.

19. 6. Wheel and Axle
Consists of a wheel that turns around a rod or axle.
Turning one turns the other

20. Wheel and Axle Examples: airplane propellers, blades on a helicopter
Doorknob
Steering Wheel or handlebars
Wheels on a car, bike, wagon, etc.
Wheels and Axles with teeth that fit one another are called gears.

21. Compound Machines
Several simple machines working in conjunction with each other can create compound machines.

22. Examples: Compound Machines bicycle can opener cars and trucks
pencil sharpener
music box

23. DO!! 5 3 6 2 1 4

24. DO!! Wheel and Axle Fixed Pulley Wheel and Axle 2nd Class Lever Wedge
1st Class Lever
Screw
Inclined Plane
Inclined Plane
Wheel and Axle
1st Class Lever
1st Class Lever
Moveable Pulley

25. Keys to Understanding At LEAST 5 complete sentences
Summarize the main points of the lesson
Describe in detail the important ideas
Write about concepts you want to remember
This should be helpful to YOU!