Tarmac is a process for paving roads. Its contribution to modern society is obvious. Amazingly, it was discovered purely by accident.
It started in the 18th century. John MacAdam, an inventor, discovered a way of creating roads—adding gravel to the surface. This was called “macadamizing”. This was an improvement over a dirt road, but the gravel had a tendency to disintegrate over time. This was not an issue for horse drawn carriages, but it was rough on motor cars. When they would move across the road, rocks would fly, and dust clouds would form.
Then In 1901, British businessman E. Purnell Hooley noticed a large barrel of tar (from a nearby factory) had spilled on the road. Someone had tried to cover it by pouring gravel on it. This would have escaped most people’s attention, but the observant Hooly noticed that the affected area of the road seemed to have less dust.
Realizing the potential of the substance, Hooley immediately started experimenting with pavement mixture, and set up a company to distribute his invention. He called the company Tar Macadam. By 1905 “tarmac” was widely used, though it was run under different management.
Though Tarmac is considered to be a registered trademark, the British use it to describe any kind of paved road. The Americans tend to use it in the context of airplane runways, since it was the main material used in making them during the second world war.
Tarmac is also called “blacktop” because of the deep dark color.