There are mainly 6 types of simple machines.
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A lever
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Pulley
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Wheel and axle
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Wedge
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Screw
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Inclined plane
Lever
A lever is a simple machine consisting of a rigid rod which is capable of turning around a pivot called a fulcrum.
It has three parts, namely, effort, load and fulcrum.
- Fulcrum: The point on which the lever turns or balances. The rod of the lever rests on it and the lever rotates on it.
- Load: The weight lifted by the lever is called the load.
- Effort: The force applied on the other end of the rod to lift the load is called the Effort.
Types Of Lever
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First class Lever / Class one Lever (Load -Fulcrum – Effort )
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Second Class Lever/ Class two Lever(Fulcrum – load– Effort )
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Third Class Lever/ Class Three Lever (Fulcrum – Effort – Load )
Read More -Types Of lever
Pulley
A pulley is a wheel that carries a flexible rope, cord, cable, chain, or belt on its rim. The pulley is designed to support movement and change the direction of the cable.
Simple Pulley
A pulley is a simple machine used to lift heavy objects.
- A pulley consists of a wheel with a grooved rim and a rope, chain, or belt wound around it.
- The wheel rotates around an axle.
Example: The Garage door is an example of pulley
Types Of pulleys
Pulleys are of the following two types:
Fixed pulley
- This type of a pulley has a fixed axle.
- A fixed pulley makes work easier by changing the direction of the force.
- This type of pulley is used to draw a bucket of water from a well.
Movable pulley
- This type of a pulley has a free or movable axle.
- It is used along with a fixed pulley.
- For example, a crane uses both fixed and movable pulleys to lift heavy loads.
Activity to demonstrate Working of Pulley
Aim: To demonstrate the working of pulley
Materials: A half-meter long, strong thread, a spool of pulley of a thread, a long pencil, a heavy bangle, a table, and many small books
Procedure:
- Pass the pencil through the spool.
- Make two stacks of books. (Keep them apart on the table).
- One end of the pencil should be kept on each stack of the books. [Note: The pencil with the spool should be at least two feet above the table],
- Pass the thread over the rim of the spool. Tie one end of the thread to the bangle.
- Now pull the other end of the thread.
Observation: The bangle is lifted up on pulling the other end of the thread.
Conclusion: The spool acts like a pulley. It is a simple machine that helps to lift heavy objects.
Wheel And Axle
A wheel and axle is a simple machine made up of a wheel rigidly attached to a rod (called an axle).
When one rotates the wheel, the axle also rotates.
Example Of Wheel And Axle
A steering wheel and a doorknob are examples of wheel and axle.
Inclined Plane
- An inclined plane is a tilted surface or a slope
- An inclined plane is used to move a heavy load with less effort
Example: Ramps in hospitals and slides on the playground are examples of inclined planes.
Screw
- It is a kind of simple machine in which nail with grooves cut on it.
- A screw is a modified inclined plane
- It has a groove at its head into which the tip of a screwdriver fits easily.
- It is used to hold things tightly together. Screws are used in objects such as light bulbs.
- It has a thread, that is a winding edge and which is an inclined plane wrapped around the screw.
- With the help of a screwdriver it is easy to drive screws into wooden blocks.
- A Screw jack is a big screw which works on the principle of screw and it is used to lift cars , trucks etc.
Example: The bottle caps are examples of screw.
Wedge
- A wedge is a simple machine that has a long triangular shape with one broad or blunt end, and one sharp end.
- The sharp end is used to cut or slice objects.
- A wedge may also be formed when two inclined planes are joined together.
Examples: The head of an axe and the blade of a knife are examples of a wedge.
Activity Demonstrate the Working of Wedge
Aim: To demonstrate the working of a wedge
Materials: A knife, an apple, a pencil, and a plate
Procedure:
1 . Place the apple on the plate
. 2. Try to cut it into two halves with the help of the pencil.
- Next try to cut it into two halves with a knife.
Observation: It is not possible to cut the apple with the pencil. But it is easily cut with the knife.
Conclusion: Knife is a simple machine.
