Gun

A gun is a remarkable device designed to propel projectiles through the use of pressure or explosive force. While the most common projectiles are solid, guns can also utilize pressurized liquids, as seen in water guns and cannons, or gases, such as in light-gas guns. The projectiles can be free-flying, like bullets and artillery shells, or tethered, as with Tasers, spearguns, and harpoon guns. The evolution of guns has led to the classification of large-caliber guns as cannons, while hand-held versions are referred to as firearms.

The propulsion of projectiles varies based on the design of the gun. Traditionally, this is achieved pneumatically through high gas pressure contained within a barrel tube, known as the gun barrel. This pressure is generated either by the rapid combustion of propellants, as seen in firearms and cannons, or through mechanical compression, as in air guns. The high-pressure gas is introduced behind the projectile, accelerating it down the barrel and imparting enough velocity to reach its target once it exits the muzzle.

Historically, the first devices recognized as guns or proto-guns emerged in China around the year one thousand. By the end of the thirteenth century, these devices had evolved into what we now consider true guns—metal barrel firearms capable of firing single projectiles that occluded the barrel. The technology and use of gunpowder spread throughout Eurasia during the fourteenth century, marking a significant advancement in weaponry.