The standard state of a substance does not have to exist in nature: for example, it is possible to calculate values for steam at 298.15 K and 10 5 Pa, although steam does not exist (as a gas) under these conditions.
A Mesopotamian wheel. Photo source. One of the reasons why the wheel was invented only at this point in history is due to the fact that metal tools were needed to chisel fine-fitted holes and axles. This leads to the next reason â the wheel was not just a cylinder rolling on its edge. It was a cylinder that was connected to a stable, stationary platform.
It was one of the biggest achievements in history. The earliest known use of this essential invention was a potter's wheel that was used at Ur in Mesopotamia as early as 3500 BC. The first use of the wheel for transportation was on Mesopotamian chariots in 3200 BC.t was one of the biggest achievements in history. The earliest known use of this essential invention was a potter's wheel that was used at Ur in Mesopotamia as early as 3500 BC. The first use of the wheel for transportation was on Mesopotamian chariots in 3200 BC.