Types of machines
Machines come as two major kinds — Simple Machines and Complex Machines.
A simple machine is a tool, device or object with few moving parts that help us do work. Simple machines have been in use for a very long time. Early humans used simple machines to push, pull, lift, divide and crush things. They used simple machines to row rafts over water, build houses, split firewood, and carry heavy things from place to place. Today, there are simple machines in every place and all around us.
There are six types of simple machines — the inclined plane, the wedge, the screw, the lever, the wheel and axle, and the pulley. These six have very specific features and do unique jobs, even though some may work in similar ways. In fact, some simple machines may be a combination of simple machines.
Simple machines, unlike complex ones, do not work on their own. They only increase the pull or push, (force or effort) that a person uses, increase or decrease the distance, or change the direction of a movement so that more work can be done. They can:
transfer a force from one place to another
change the direction of a force
increase the magnitude of a force
increase the distance or speed of a force
Features of a simple machine
They do not use electricity
They have one or fewer moving parts
They give us mechanical advantage
Even though they make work easier for us, they still need input (force or effort) from a person.
They make tough jobs easier by changing the force, direction or speed of a movement
Simple machines are different from complex (or compound machines). Complex machines, like trucks or wagons, or bicycles use many moving parts. They combine many simple machines such as levers, pulleys, and gears to get work done.
Now, we shall look at each example of a simple machine.