Man began to invent the wheel about 20 thousand years ago. It was something like this.
Once an ancient man decided to hollow out a boat from a tree trunk ‚to sail to new lands. Just how to drag this tree to the river? You can chop the knots so as not to cling! - suggested tribesmen, chopped off! Carried! ..
And so dragged for several hundred years. Until the smartest one shouted: “Guys! It’s easier to drag when the boat glides over fallen tree trunks. ”So the ancestor of the wheel appeared - a simple log! This wheeled great-grandfather was used by the ancient Egyptians to build their pyramids. And then people invented a miraculous wagon. A wooden platform, and under it several logs. Ride on it wasn’t easy - the logs all the time “ran up”, and their center rubbed against the platform! But the ends of the trunks sticking out from under the wagon remained thick. “Well and good!” thought the ancient people. “So the wagon rolls faster.” They decided yourself about igat middle log.
And then they thought of taking a thin stick - the axis - and putting on it round wheels - wheels! And finally, 5 thousand years ago in Mesopotamia, a man first climbed into a two-wheeled cart!
The first wheels were wooden with a hole in the middle. “So we will translate all the trees!” - people noticed and thought for about 2 thousand years. And then in Egypt they invented a four-spoke wheel. A thousand years later, an eight-spoke wheel appeared in Greece. He was lined with leather, and the rim was lined with iron nails. Soon, the rim began to be made of iron. How a bird drove a wagon on such wheels!
But people did not stop there. And they still invent wheels for moon rovers, cars and robots.