Simple machines

All simple machines work by changing a force, either by transferring it, magnifying it, or changing its direction. Simple machines are often used as building blocks to produce more complicated machines. 

For example, you can find 3 simple machines within a bicycle: levers, pulleys, and the wheel and axle.

Prior to the wheel, large items were placed on log rollers. As the object was moved forward logs were taken from the back and moved to the front. Another method of transportation was to have animals drag heavy objects along the ground.

Around 5,000 years ago, a wheel was placed on an axle and changed the world. The technology first appeared in Poland and was independently invented by the Chinese soon after. 

A wheel attaches to a straight rod called an axle. These 2 parts rotate together to reduce friction between the wheel and the ground. Friction that occurs at the point where the wheel and axle meet can be decreased by the addition of bearings.

Considered to be one of the most significant inventions in the history of humanity, the wheel and axle allowed humans to move large objects over great distances. It accelerated the spread of trade as goods were transported with ease to faraway markets. 

As with all simple machines, the wheel and axle combination multiplies force. This means it takes very little effort to create a large amount of force. And the bigger the wheel, the easier it is to push as it works like a big lever.

Simple machines (with the exception of the wheel and axle) only need 1 part in order to work. Although simple machines were described some 2,000 years ago it wasn’t until the Renaissance in the 17th century that the physics behind these machines were studied.

Galileo was the first scientist to describe the mathematical similarity of the machines in 1600.

The inclined plane, also called a ramp, was not considered a machine until the Renaissance. This is mainly because inclined planes have no parts that move in order to change force. 

 An inclined plane is basically a sloping surface. Inclined planes are commonly used to either move objects from a lower point to a higher point or the other way around. 

Objects increase force when they are rolled down an inclined plane. This rate can be changed based on the angle of the inclined plane. Moving an object up an inclined plane takes less force than lifting the same object straight up. 

The cost of moving an object to a higher area using an inclined plane is the distance needed to move the object. The steeper the angle, the more force is needed. To make the work easier, some inclined planes need to be quite long.