The invention of wheel has proved to be one of the biggest blessings for the mankind. It is used in almost all modes of transportation: trains, buses, trucks, cars, aeroplanes, scooters, cycles, rickshaws, bullock carts, etc. It has become very easy to cover long distances in a short time, thanks to the wheel.
Before the invention of wheel, man himself carried the load. Later on, he started taming the animals like oxen, donkeys, horses and camels and used them for carrying their load. Gradually man started carrying load by dragging wood planks with the help of animals. Stone Age people may have learned to roll loads along on logs. The oldest known wheels looked like slices cut across a log with a hole in centre. Each solid disc was made of tree parts. After this invention, two wheels were joined by an axle and the axle was fastened to a platform of wood. This was the first crude cart of the world. In this cart both the wheels and the axle used to move.
Later, a sophisticated version of wheel was developed. Wheels were made in ancient Mesopotamia (modern Iraq) between 3,500 BC to 3,000 BC. The picture of a cart wheel appears on some clay tablets from Mesopotamia dating 3,500 BC. About 2500 BC wheel was in use in Indus valley also.
The next improvement in the use of wheel was fastening the axle to the vehicle and letting the wheels spin freely. The first wheeled vehicles were bullock carts, war- chariots and four-wheeled carts of the gods. Gradually the spoke wheel was invented in Asia about 2000 BC. This reduced the weight of the wheel considerably.
With the passage of time, numerous improvements have been made in the design of wheels. Today, we have the rims and spokes of the wheels made of iron. Rubber tyres and tubes are put around them. To make tyres durable, nylon fabrics are used in rubber solution. Rubber tyres are so designed that these can have firm grips over the road surface to avoid skidding. Now wheel has become lighter, more efficient and long lasting. The invention of an unknown genius carried us a long way along the path of technology and civilization.
