The six simple machines can be combined into complex machines to allow us to have to exert less force when doing work. The six machines are the lever, pulley, inclined plane, wheel and axle, wedge and the screw. There are many ways that these machines can be added to one another to allow us to do many activities we couldn’t accomplish on our own.
Create a device to pick up, cut or move certain objects by combining a lever with a wedge. Simply connect a long cylindrical piece of wood to a flat piece of metal with a sharp edge. This will create a shovel. Much more snow or dirt can be collected and moved by adding these two machines together. Another example of a lever and a wedge is a pair of scissors consists of two levers with wedges as cutting edges.
Create a complex machine to move a heavy object by adding a pulley to an inclined plane. Simply place the heavy object at the bottom of an inclined plane (a ramp) and attach the weight to a pulley system using a rope. Pull on the rope on the other end of the pulley and you will be able to move the weight much more easily. This is one of the reasons you will see ramps and pulleys in the back of many moving trucks.
Combine a lever and a wheel and axle to allow you to move objects more easily from place to place. A wheelbarrow is an example of this complex machine. Attach two levers (the handles) to a plastic or metal container with a wheel and axle underneath it. This combination makes it a lot easier to move a heavy mound of dirt and rocks that would have taken much longer to move from place to place one by one.
Create a complex machine that moves substances from a lower location to a higher location by combining an inclined plane and a screw. The Archimedes screw was invented in ancient Egypt and it allows for water to be irrigated from a mine or a ship to a higher location. Place a screw simple machine around a piece of wood or metal and place it on an incline like a hill. The screw turns and water moves up the incline to a basin up above. Most industrial pumps today are based on this Archimedes screw concept.
Attach a pulley and a lever as a way to add to the pulley and inclined machine of step 2. Instead of pulling the rope part of the pulley, you attach a lever to the other end of the rope, which makes pulling the load up the inclined plane even easier. Pulleys and levers can be found together in construction equipment like cranes and hydraulic lift systems.