Science Projects And Inventions

Bow and Arrow

"Whose arrows are sharp, and all their bows bent, their horse's hoofs shall be counted like flint...."
Isaiah 5:28
Evidence of the early use of bows and arrows has been found in cave paintings in Western Europe and North Africa. Its development probably arose in the Upper Paleolithic (Old Stone Age) around 20,000 B.C.E., when people realized that the weapon would enable hunters to kill outside their throwing range.
Bows and arrows were portable, easy to make, and the materials to make them were relatively easy to obtain. The bow consisted of a thin flexible shaft of wood; this was bent, and a length of sinew, deer gut, plant fiber, or rawhide was strung tightly between its ends. Sometimes the bowstring was twisted to make it stronger. Ash, mahogany, and yew were all used for bows. Sometimes the wood was backed with sinew to make the bow stronger and stop it breaking.
The arrow was a thin shaft of wood, sharpened at one end, with feathers attached to the other to give it aerodynamic stability. Arrowheads were made from flint or other rocks, antler, or bone.
The bow was the first machine that stored energy. Energy from the archer's muscles gradually transferred to the bow as it was drawn back; when the bow was released, it gave the projected arrow a far greater velocity than that produced by a spear-thrower. In about 1500 B.C.E. a shorter and lighter bow was developed, the composite bow. Short and curved, it was built up from layers of materials that reacted differently under tension or compression. It was an accurate weapon to use from horseback.
Modern bows are made from fiberglass, carbon, and aluminum as well as wood, while the arrows are usually made of composite materials. 


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