Types of Simple Machines - Science Class 5

In this video, you will learn all about Types of Simple Machines.
There are six different types of simple machines—lever, wheel and axle, pulley, inclined plane, wedge and screw.
Lever
A lever is a rod that can turn around a fixed point. This can be used to raise or move a heavy object without actually lifting it.
Parts of a lever
• The fixed point or the support around which the rod moves is called the fulcrum (F).
• The force which we apply to move the object is called the effort (E).
• The object which we are trying to move or lift is called the load (L).
Depending upon the relative positions of the fulcrum, the effort and the load, levers are divided into three types—first class lever, second class lever and third class lever.

First class lever
When the fulcrum is between the load and the effort, it is called a first class lever. Examples: Claw hammer, pliers, scissors, crowbar and seesaw.

Second class lever
When the load lies between the fulcrum and the effort, it is called a second class lever.
Examples: Wheel barrow, nut cracker, hole puncher and bottle opener.

Third class lever
A lever in which the effort is between the load and the fulcrum is called a third class lever. Examples: Human arms (lifting something), fishing rod, tweezers, stapler and sugar tongs.

Wheel and Axle
A wheel and axle comprises a wheel rigidly attached to a rod at its centre called an axle. It works on the principle that a lesser force is needed to turn a wheel than to turn an axle, thus, making the work easier. A sewing machine, a steering wheel, a cycle and grinding machines have wheels and axles.

Pulley
A pulley consists of a rope or a chain that moves over the grooved rim of a wheel. It is used to lift, lower or move heavy loads. It is often used to move loads to places that are hard to reach. When a pulley is used, lesser force is needed to lift the load. In a pulley, the effort can be applied in one direction and the load can be moved in another direction, i.e., we can change the direction of the force applied. There are two types of pulleys—fixed and movable pulley.

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