Machines are used to make a task easier. They reduce the amount of effort that we need to put in (the force) to lift or move a heavy object (the load). Machines can also change the direction of a force, so we can move things in a more helpful way.
Lever
A lever is a bar that swivels on a fixed point, called a fulcrum, and makes it easier to lift a heavy load. If you push down at one end of the lever, the load at the other end is raised.
Slope
It is much easier to push or pull something heavy up a slope than it would be to lift it straight up because less force is needed. However, you have to push or pull the object a greater distance to get it to the same place.
Gears
Gears are wheels with teeth that fit together. When one gear is turned, the other one turns in the opposite direction. If the gears are different sizes, they turn at different speeds.
Wedge
A wedge helps us to push things apart. The blade of an axe is a type of wedge. When the axe is swung and the blade hits a piece of wood, the wedge forces the wood to split apart.
Pulley
A pulley makes it easier to lift a heavy object (load) straight up. A rope is looped over a wheel and one end of the rope is attached to the load. It is easier to lift the load by pulling down on the rope than by picking it up.
Wheels and axle
A wheel and axle work as a turning machine that makes it easier to move something from one place to another. When the axle is turned, the rim of the wheel turns more quickly.
Screw
A screw changes a small turning force into a large downwards force. It has a spiral pattern, called a “thread”, which runs round the screw. Each time the screw is turned, the thread pulls it down a bit.
Picture Credit : Google
