Bow and arrow



The bow and arrow is a projectile weapon system (a bow with arrows) that predates recorded history and is common to most cultures. Archery is the art, practice, or skill of applying it.

Description
A bow is a flexible piece of material which shoots aerodynamic projectiles called arrows. A string joins the two ends and when the string is drawn back, the ends of the stick are flexed. When the string is released, the potential energy of the flexed stick is transformed into the velocity of the arrow. Archery is the art or sport of shooting arrows from bows.

Today, bows and arrows are used primarily for hunting and for the sport of archery. Though they are still occasionally used as weapons of war, the development of gunpowder and muskets, and the growing size of armies, led to their replacement in warfare several centuries ago in much of the world.

Someone who makes bows is known as a bowyer, and one who makes arrows is a fletcher —or in the case of the manufacture of metal arrow heads, an arrow smith.

History


The bow and arrow was not the first composite projectile weapon to be invented. It was preceded by the sling and by spear throwers such as the atlatl of the Americas and the woomera of Australia. A number of cultures in historical times lacked the bow and arrow, and in others oral history records a time before its acquisition.

The earliest potential arrow heads date from about 64,000 years ago in the South African Sibudu Cave. By 16,000 BCE flint points were being bound by sinews to split shafts. Fletching was being practiced, with feathers glued and bound to shafts.

The first actual bow fragments are the Stellmoor bows from northern Germany. They were dated to about 8,000 BCE but were destroyed in Hamburg during the Second World War, before carbon 14 dating was available; their age is attributed by archaeological association. The oldest bows in one piece are the elm Holmegaard bows from Denmark which were dated to 9,000 BCE. High performance wooden bows are currently made following the Holmegaard design.

The bow and arrow are still used in tribal warfare in Africa to this day. An example was documented in 2009 in Kenya when the Kisii-tribe and Kalenjin-tribe clashed resulting in four deaths.

Parts of the bow
The basic elements of a bow are a pair of curved elastic limbs, traditionally made from wood, joined by a riser. Both ends of the limbs are connected by a string known as the bow string. By pulling the string backwards the archer exerts compressive force on the string-facing section, or belly, of the limbs as well as placing the outer section, or back, under tension. While the string is held, this stores the energy later released in putting the arrow to flight. The force required to hold the string stationary at full draw is often used to express the power of a bow, and is known as its draw weight, or weight. Other things being equal, a higher draw weight means a more powerful bow, which is able to project arrows heavier, faster, or a greater distance.

The various parts of the bow can be subdivided into further sections. The topmost limb is known as the upper limb, while the bottom limb is the lower limb. At the tip of each limb is a nock, which is used to attach the bowstring to the limbs. The riser is usually divided into the grip, which is held by the archer, as well as the arrow rest and the bow window. The arrow rest is a small ledge or extension above the grip which the arrow rests upon while being aimed. The bow window is that part of the riser above the grip, which contains the arrow rest.

In bows drawn and held by hand, the maximum draw weight is determined by the strength of the archer. The maximum distance the string could be displaced and thus the longest arrow that could be loosed from it, a bow’s draw length, is determined by the size of the archer.

A composite bow uses a combination of materials to create the limbs, allowing the use of materials specialized for the different functions of a bow limb. The classic composite bow uses wood for lightness and dimensional stability in the core, horn to store energy in compression, and sinew for its ability to store energy in tension. Such bows, typically Asian, would often use a stiff end on the limb end, having the effect of a recurve. In this type of bow, this is known by the Arabic name 'siyah'.

Modern construction materials for bows include laminated wood, fiberglass, metals, and carbon fiber components.

Arrows
An arrow usually consists of a shaft with an arrowhead attached to the front end, with fletchings and a nock at the other. Modern arrows are usually made from carbon fibre, aluminum, fiberglass, and wood shafts. Carbon shafts have the advantage that they do not bend or warp, but they can often be too light weight to shoot from some bows and are expensive. Aluminum shafts are less expensive than carbon shafts, but they can bend and warp from use. Wood shafts are the least expensive option but often will not be identical in weight and size to each other and break more often than the other types of shafts. Arrow sizes vary greatly across cultures and range from very short ones that require the use of special equipment to be shot to ones in use in the Amazon River jungles that are 8.5 ft long. Most modern arrows are 22 in to 30 in in length.

Arrows come in many types, among which are breasted, bob-tailed, barrelled, clout, and target. A breasted arrow is thickest at the area right behind the fletchings, and tapers towards the nock and head. A bob-tailed arrow is thickest right behind the head, and tapers to the nock. A barrelled arrow is thickest in the centre of the arrow. Target arrows are those arrows used for target shooting rather than warfare or hunting, and usually have simple arrowheads.

Arrowheads
The end of the arrow that is designed to hit the target is called the arrowhead. Usually, these are separate items that are attached to the arrow shaft by either tangs or sockets. Materials used in the past for arrowheads include flint, bone, horn, or metal. Most modern arrowheads are made of steel, but wood and other traditional materials are still used occasionally. A number of different types of arrowheads are known, with the most common being bodkins, broadheads, and piles - or a simple conical head used for target shooting. Bodkin heads are simple spikes made of metal of various shapes, designed to pierce armour. A broadhead arrowhead is usually triangular or leaf-shaped and has a sharpened edge or edges. Broadheads are commonly used for hunting. A pile arrowhead is a simple metal cone, either sharpened to a point or somewhat blunt, that is used mainly for target shooting. A pile head is the same diameter as the arrow shaft and is usually just fitted over the tip of the arrow. Other heads are known, including the blunt head, which is flat at the end and is used for hunting small game or birds, and is designed to not pierce the target nor embed itself in trees or other objects and make recovery difficult. Another type of arrowhead is a barbed head, usually used in warfare or hunting.

Bowstrings
Bowstrings may have a nocking point marked on them, which serves to mark where the arrow is fitted to the bowstring before firing. The area around the nocking point is usually bound with thread to protect the area around the nocking point from wear by the archer's hands. This section is called the serving. At one end of the bowstring a loop is formed, which is permanent. The other end of the bowstring also has a loop, but this is not permanently formed into the bowstring but is constructed by tying a knot into the string to form a loop. Traditionally this knot is known as the archer's knot, but is a form of the timber hitch. The knot can be adjusted to lengthen or shorten the bowstring. The adjustable loop is known as the "tail".

Bowstrings have been constructed of many materials throughout history, including fibres such as flax, silk, and hemp. Other materials used were animal guts, animal sinews, and rawhide. Modern fibres such as dacron or kevlar are now used in bowstring construction, as well as steel wires in some compound bows. These compound bows have a mechanical system of pulley cams over which the bowstring is wound.

Types of bows
There is no one accepted system of classification of bows. Some systems classify bows as either longbows or composite bows. In this system, a longbow is any bow that is made from one material. Composite bows are made from two or more layers of different materials. Other classifications divide bows into three types — simple, backed, and composite. In this scheme, simple bows are made of one material, backed bows are made of two layers, which could be similar or different materials. Composite bows are made of three different layers, usually different materials, but occasionally two of the layers are made from the same material.

Common types of bows include:
 * Recurve bow: a bow with the tips curving away from the archer. The curves straighten out as the bow is drawn and the return of the tip to its curved state after release of the arrow adds extra velocity to the arrow.
 * Reflex bow: a bow that curves completely away from the archer when unstrung. The curves are opposite to the direction in which the bow flexes while drawn.
 * Self bow: a bow made from one piece of wood.
 * Longbow: a self bow that is usually quite long, often over 5 ft long. The traditional English longbow was usually made of yew wood, but other woods are used also.
 * Composite bow: a bow made of more than one material
 * Compound: a bow with mechanical aids to help with drawing the bowstring. Usually, these aids are pulleys at the tips of the limbs.

Crossbow
In a crossbow, the limbs of the bow, called a prod, are attached at right angles to a crosspiece or stock in order to allow for mechanical pulling and holding of the string. The mechanism that holds the drawn string has a release or trigger that allows the string to be released. A crossbow shoots a "bolt" rather than an arrow.