A hammer is a striking tool, used for example to flatten a piece of iron or to drive a nail.
The hammer consists of a head and a handle. The head consists of a metal mass and acts by inertia, increased by the length of the handle and the length of the arm of the operator. A good hammer is designed so that the grip corresponds to the centre of percussion. When the head is made of a soft material such as wood or resin, it is called a mallet, and when it has at least one sharp side it is called an axe.
The hammer has existed since the beginning of human intelligence. At first it was used as a hard hammer. Already in Mesopotamia, it was used to dig in copper and tin mines. It has been used throughout the ages as the main tool of the blacksmith.
During the Middle Ages, its use expanded; it was used as a tool to drive in small pointed pieces of wood (ancestors of the nail) to nail boards together. At this time it was also used to shoe horses. Around the 1400s, it also became the tool of shoemakers, who used it to soften leather and for various other purposes.
It was not until the 19th century that its most common use, driving metal nails, was developed. From its invention to the present day, its usefulness has developed greatly and will surely continue to do so over the years.