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Presented By : Std.- 6th Sub.- Science 8. Simple machines

What is a Simple Machine? A simple machine has few or no moving parts. Simple machines make work easier

Inclined Planes An inclined plane is a flat surface that is higher on one end Inclined planes make the work of moving things easier

Screws A screw is an inclined plane wrapped around a shaft or cylinder. The inclined plane allows the screw to move itself when rotated.

Inclined Plane Wrapped around post = Screw Screw A Screw is really an Inclined Plane wrapped around a center post.

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

Single Fixed Pulley This pulley provides the user Directional Advantage, allowing someone to pull down to lift the load up. Is Mechanical Advantage provided with this system? No, the effort needed to lift this load is equal to the weight of the load. This is because the load is supported by only 1 rope arm. You must also pull an amount of rope equal to the height you wish to lift the load

Levers-First Class In a first class lever the fulcrum is in the middle and the load and effort is on either side Think of a see- saw

Levers-Second Class In a second class lever the fulcrum is at the end, with the load in the middle Think of a wheelbarrow

Levers-Third Class In a third class lever the fulcrum is again at the end, but the effort is in the middle Think of a pair of tweezers

A Class 1 Lever has its fulcrum between the effort and the load. F

A Class 2 Lever has its load between the effort and the fulcrum. L

A Class 3 Lever has the effort between the load and the fulcrum. E

Levers Quiz Use the following slides to quiz yourself on how how well you can match commonly used items with their correct class of lever.

Class 1 Class 2 Class3 Click on the correct Lever classification for the tool pictured below.

Class 1 Class 2 Class3 Click on the correct Lever classification for the tool pictured below.

Class 1 Class 2 Class 3 Click on the correct Lever classification for the tool pictured below.

Class 1 Class 2 Class 3Class 1 Class 2 Class 3 Click on the correct Lever classification for the tool pictured below.

Class 1 Class 2 Class 3 Click on the correct Lever classification for the tool pictured below.

Class 1 Class 2 Class 3Class 1 Class 2 Class 3

Click on the correct Lever classification for the tool pictured below. Class 1 Class 2 Class 3

Class 1 Class 2 Class 3 Click on the correct Lever classification for the tool pictured below.

Class 1 Class 2 Class 3

Click on the correct Lever classification for the tool pictured below. Class 1 Class 2 Class 3

Click on the correct Lever classification for the tool pictured below. Class 1 Class 2 Class 3

Click on the correct Lever classification for the tool pictured below. Class 1 Class 2 Class 3

Click on the correct Lever classification for the tool pictured below. Class 1 Class 2 Class 3

Click on the correct Lever classification for the tool pictured below. Class 1 Class 2 Class 3

You have successfully matched the common hand tools with their correct classification of lever. Be sure to remember: F L E 1 2 3

Levers can provide Mechanical Advantage by reducing the effort needed to lift a load. The closer the fulcrum is to the load, the less effort is needed to lift the load. The load does not move a great distance. E L F

Levers can be used to move loads farther if the fulcrum is placed close to the effort. In this situation more effort is needed to lift the load, but the load will move farther than if the fulcrum was closer to the load. F E L

Wheels and Axles The wheel and axle are a simple machine The axle is a rod that goes through the wheel which allows the wheel to turn Gears are a form of wheels and axles

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

Thaynks