Early humans in the Palaeolithic era (15,000 to 750,000 years ago) discovered that heavy, round objects could more easily be moved by rolling them than bulky, irregular ones. The realisation was made that some heavy objects could be transported if a round object such as a fallen tree was placed underneath and the heavy object rolled over it. However, diagrams on ancient clay tables suggest the wheel did not materialise for thousands of years until a potter’s wheel was used in Mesopotamia (modern day Iraq) in 3500 BC.
The oldest wooden wheel discovered so far was found in Ljubljana, Slovenia and is believed to date back to about 3200 BC. It was about the same time that the wheel was first used for transportation on chariots. With a need for greater speed and manoeuvrability, the Egyptians created the spoked wheel around 2000 BC, while Celtic chariots a millennium later employed iron rims for greater strength. However, the wheel remained largely unimproved until the 19th Century when Robert William Thompson invented the pneumatic tyre, a rubber wheel using compressed air which paved the way for automobile and bicycle tyres.
Wheels through the ages
The wheel has been used extensively and improved upon throughout history, but how have humans harnessed its practicality?
As shown in the illustration above, early Homo sapiens realised that round objects could be easily moved by rolling them. Their descendants advanced this rolling technique into the transportation of large objects on cylindrical logs. The invention of the wheel and axle allowed a rolling log to be placed through a hole in a wheel to create a cart. Chariot racing was influential in the evolution of the spoked wheel as they allowed chariots to move much faster. The invention of air filled rubber tyres allowed wheels to be much faster, sturdier and stronger, ultimately redefining transportation.