Simple Machines, By Ron Kurtus

Many simple machines have been created even since the early times. According to Ron Kurtus from his website article, "Simple Machines", the ancient Egyptians used levers to lift stones to build their pyramids and ramps to raise them to the top. Also he states that in Roman times, stones were tossed at enemies using catapults. The catapults used levers to fling the stones, and pulleys to pull down the arm of the catapult. The purpose of all of these simple machines is to lessen the amount of work or effort that you must put into a job. The pulley, inclined plane, gear, spring, and lever are good examples of simple machines. In the following paragraphs I will give more information about three of these, the pulley, inclined plane, and the gear.
The whole concept the pulley is based on is changing the direction of the force being applied.
Just using a wheel to allow a rope to be pulled in a different direction can be much easier on someone. A pull downward on a rope to lift something is often easier than bending over and picking the load up yourself.
Single pulleys are used in many complex machines where the direction of movement must be changed. One of the complex machines that pulleys are used in is the elevator. The elevator car is lowered or raised by large cables and a pulley at the top. The end of the cable has counterweights that balance the weight of the car and passengers. The electric motor turns the pulley so the car moves up and down. Even though you may not notice them, pulleys are everywhere such as on bikes, cable trams, ski lifts, and more.
Pulleys can also be connected to be more powerful. For instance, if you connect two pulleys together, the rope is connected around both pulley wheels. This allows more weight to be lifted since the force raising the weight is double the effort pulling the rope. Utilizing this, you can setup a block and tackle system. This is a bunch of pulleys that are connected to raise substantial loads. The amount of pulleys you have connected together is the amount of times the force you apply will be magnified. A crane is a perfect example of the block and tackle system. At the end of the cable, a block and tackle system helps increase the heavy weight the crane is able to lift.
Another simple machine, the inclined plane, is also very useful. An inclined plane is a surface that is set at an angle under ninety degrees. The required work is still the same but the way you do the work is different. By increasing the length of the plane and lowering the angle, it takes less effort. Obviously, you will be able to lift more at a lower angle than at a higher angle. Even though you must push the load a longer distance, it makes heavy things easier to lift up. One situation where an inclined is helpful is with wheelchair ramps. It would be extremely hard to lift a wheelchair with a person in it up stairs but with an inclined plane or ramp you could lighten the load.
Lastly, one other important simple machine is the gear.
As simple as it may seem, there are many different types and sizes of gears used in tons of complex machines. Sometimes they have straight teeth and sometimes they have curved or inclined teeth at various angles. They are connected in all different ways to move motion and force in machines. When they work, one gear wheel turns faster or slower than the other, or moves in a different direction. The difference of the speed between the two gears causes a change in the force given out. There are many different ways gears can be combined to be useful for various purposes. For instance, spur gears are two gear wheels intermeshed. These gears regulate the speed or force of motion and can reverse direction. Next, there are rack and pinion gears. They are comprised of one wheel, the pinion, and a sliding toothed rack. This allows a rotating motion to be changed into a back and forth motion. Rack and pinion gears are often used in steering cars. These and other gears are used in numerous complex machines. A washing machine is comprised of spur gears to turn the
dials.
All in all, the invention of simple machines has completely changed the world. From these simple machines, complex and involved machines have evolved. Simple machines have allowed even primitive people to accomplish tasks they would otherwise not be able to do. In the book, The New Way Things Work, author David Macaulay says that several thousand years ago Archimedes invented a compounded pulley which could pull a ship to shore. Even to break a large bolder into smaller rocks would be nearly impossible without the inclined plane to lighten the force you must apply. When it all comes down to it, without simple machines today's world would be much less complex. We might still be trying to invent simple clocks instead of complicated computers!