THE WHEEL.

Imagine that you live in a desolate place, no cars no trains no bicycles. and you have to take it walking to your destination! that was how our first humans from the ancient ages used to do when they intend to travel to a faraway place. since thousands of years, the first humans started to settle down and make up small villages near rivers and sweat lakes, built small houses and then discovered castles and palaces then built his own civilization, they developed agriculture and industries followed upon the various needs human uses.

An imaginary photo of the Sumerian civilization

and by developing the bicycle the human race has accomplished one of his biggest leaps in the modern age, to know what I mean by a big leap just put a heavy book on the table and try to bush it by your hand, then try again by putting 3 pencils under the book and try again. the friction of the book with surface of the table makes it harder to push it but the pencil reduced the friction by nearly %70, maybe the ancient Egyptians have realized this fact and tried to use the palm tree under the heavy stones.

Ancient Chinse cart

We will never know who is the first used the bicycle, but we know the ancient people of Asia used bicycles under their transportation little carts, that was 4000 years ago!!, and the bicycles were a  small solid 2 wooden disks tensioning with a front axis under a small cart, in the beginning, those carts were pulled by humans then the bulls and horses were used.

Ancient Egypt.

in 1750 B.C. the ancient Egyptians used heavy duty wheels extended from the upper of the wheel till it's frame which is in touch with the ground. and this bicycles was lighter and faster carts, that's why the ancient Egyptians could frighten their enemies with the carts speed and efficiency.
Then the Romans used to make heavy duty wheels from steel instead of wood that was used by the ancient Egyptians, it was much tougher but much heavier.
In the modern age, In the car, for example, the wheels are much complicated.

An overview of a porch car components

the wheel is connected to a shaft and the shaft is connected to a gearbox and the gearbox is connected to the transmission arm. when the wheel is turning around its fixed axis, the friction of the wheel is focused on the housing which is loaded with bearings and lubrication oil to reduce friction and prolong the wheel life.