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?

Machines Chapter 21, Section 3 Standards: 11.1 - Differentiate between the six simple machines. 11.2 - Determine the amount of force needed to do work using different simple machines.

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

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.

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

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.

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

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

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

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

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

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

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

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

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

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

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)

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.

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

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.

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

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

DO!! 5 3 6 2 1 4

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

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!