Helmet

A helmet is a form of protective gear worn on the head to protect it from injuries, a variation of the hat. The oldest use of helmets was by Ancient Greek soldiers, who wore thick leather or bronze helmets to protect the head from sword blows and arrows. In the 2000s, soldiers still wear helmets, now often made from Kevlar rather than metal, to protect the head from bullets and shell fragments.

Helmets were among the newest forms of combat protection, and are known to have been worn by Romans, throughout the Middle Ages, and up to the end of the 1600s by many combatants. At that time, they were purely military equipment, protecting the head from cutting blows with swords, flying arrows, and low-velocity musketry. Some helmets, in order to protect the neck as well, have a sort of extension made of leather strips called pteruges, particularly common in the Middle East.

Helmets used for different purposes have different designs. For example, a bicycle helmet would chiefly need to protect against blunt impact forces from the wearer's head striking the road or a car hood. A helmet designed for rock climbing, however, would need to protect against objects (e.g. small rocks and climbing equipment) such as an ice axe falling from above. Practical concerns also dictate helmet design: a bicycling helmet would preferably be aerodynamic in shape and probably well ventilated, while a rock climbing helmet would be lightweight and with a minimum of bulk so that it would not interfere with climbing.

Baseball batting helmets have an expanded protection over the ear, which protects the jaw from injury. Motorcycle helmets often have flip-down face screens for rain and wind protection, and they may also have projecting visors to protect the eyes from glare. Hard hats for construction workers are worn mainly to protect the wearer from falling objects such as tools. Helmets for riot police often have flip-down clear visors and thick padding to protect the back of the neck. Modern firefighter's helmets protect the face and back of the head against impact, fires and electricity, and they can include masks, communication systems, and other accessories. Welding helmets protect the eyes and face and neck from flash burn, ultraviolet light, sparks and heat. They have a small window, called a lens shade, through which the welder looks at the weld; for arc welding this window must be much darker than in blowtorch goggles and sunglasses.