If you want to explain the concept of simple machines to children, the easiest definition that you can use is that these are machines that help make our work much easier. Or you can define them as mechanical devices that ease the effort that you have to put into a certain task. Inventing simple machines was probably one of the first inventions of human kind, with tools like stones and sticks being used to reduce effort. It was only in 1600 AD though, that Galileo Galilei put forward the theory of simple machines in his book Le Meccaniche, in which he stated that these do not generate energy but they transform it.
Simple machines reduce effort by either transferring a force, changing the direction of force, increasing the magnitude of force, or increasing the speed of force. The six different kinds are explained below.
The basic function of an inclined plane is to be able to either lift up or to lower an object. The surface of a plane is flat and when placed in a slanted manner it is known as an inclined plane. The principle on which it works is that you can move a large bulk for a long distance by applying slight force. Moving an object on an inclined or slanted surface is much easier than a straight surface.
The lever which is a bar-like rigid object moves against a turning point to move a third object. The turning point against which it moves is known as the fulcrum and the closer the object that needs to be moved is to the fulcrum, the easier it is to move the former. There are three types of levers; first-class lever, second class lever, and third class lever.
In this simple machine one end of a cord is attached to the load that needs to be moved, placed over a wheel and as you pull on one side, according to the direction in which you exert force, you can move the load forward or backward. If you are looking for interactive simple machines, then try to make a model of a flag which is being hoisted. It uses the pulley system.
Many people consider screw to be a modified version of the inclined plane which differs in shape because of its helical appearance. It uses the principle of transfer of energy, converting rotational force into linear force in the process of performing a task. On one end of an inclined plane is a helical and on the other end is a provision that you can use to turn it. Screws are used to hold objects together and even to raise weights.
It is made of two inclined planes and can move. The point of contact of the two inclined planes results in a sharp edge which can be used to cut and split objects and to hold them together. A wedge is shaped in such a manner that it is triangular in appearance. Examples of wedges that we use in daily life include forks, knives, and even our teeth.
Wheel and Axle
There are many games that you can play to explain the concept of the wheel and axle. You can use simple toys to explain the principle of this simple machine. The axle is the rod that is speared through the wheel to rotate it. The axle converts rotational force into linear force propelling the object forward.
Using lesson plans, you can come up with many ideas for simple machines that can be made easily. Most machines that we use nowadays have their basis in the principles on which these simple machines work.