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Real World Physics Problems Newsletter - Wheel Physics, Issue #16
February 26, 2015

The Wheel

picture of wheel

Source: Wikimedia via Biswarup Ganguly

The wheel is a very simple mechanical device. It was invented thousands of years ago and its basic design has not changed at all through the ages. Wheels are used in all forms of transportation and they provide the most efficient way to travel on land.

They are also found nowhere in nature. They are 100% a product of technological invention. Unlike other simple machines, such as the lever, the wheel is not utilized by anything in nature. Nothing in nature even comes close to using the wheel as a serious mode of transport. Contrast this to the lever, the principle of which is utilized in the limbs of animals (joints) to provide movement.

The inclined plane, another type of simple machine, is found on sloping ground, such as hills, which provide easier passageway for animals to increase or decrease their elevation as opposed to, say, a steep cliff.

The wedge, another simple machine, is also found in nature anywhere an object is pressed in between two other objects and tends to push them apart as a result.

The remaining simple machines are derivatives of those already mentioned. The screw is a form of inclined plane, and pulleys consist of wheels and axles.

All simple machines except the wheel and derivatives of the wheel (pulleys), are found in nature in some form, either by way of natural structures on earth or inside the anatomy of animals.

The wheel is missing from nature and from the anatomy of animals. So why is this the case? It's an intriguing question but I think the explanation for animals is fairly simple. Wheels must continuously move relative to their supports. It is for this reason that the anatomy of an animal cannot contain a wheel for locomotion. It can't be connected to the rest of the animal, and as a result it cannot receive nourishment via blood vessels, which also means it cannot grow with the rest of the animal. Imagine having muscles and blood vessels connected to a body part in the shape of a wheel. As the wheel turns the muscles and blood vessels would twist and twist until they choke off, so it just would not work.

Wheels are not part of the natural earth terrain for likely the same reason. They are a disjointed structure which must move freely relative to its support, and the formation of the earth and its landscape does not seem to allow for this to happen. Mountains form, the ground shifts, and erosion occurs. This creates a variety of shapes and structures, but not the wheel since it is just too organized a structure for it to be created through the natural processes which shape the earth.

This suggests that certain fundamental aspects of technology, such as the wheel, cannot be duplicated anywhere in nature. Some things are solely a product of human invention.

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