Prpjectiles

projectile1.jpg
Anything can become a projectile once it has been thrown, shot, slung, hurled, etc.
History of Projectiles:
Some of the first projectiles were most likely stones, clubs, and spears. These were probably the first things to be thrown at one another or at game for hunting purposes. They could have been ultized for fighting, war, sport, or boredom. Technology has driven the history of projectiles over the years. The first projectiles such as stones, and lengths of wood were updated and enhanced. The stones were put into slings and resulting hurled further and faster. Lenghts of wood that we refer to as spears now were put onto curved pieces of bone or wood and held in place by the hand the spear could be thrown better. These spear throwers were refered to as Atlatl's.
Stones and spears did not quickly evolve. For thousands of years they were used in relatively the same way. This was until the advent of the bow. The bow dates back to 64,000 years ago in Africa. The bow ultized elastic energy better than earlier slings and Atlatl's. The bow is stil a primitive weapon by today's standards but at the time it was on the cutting edge of technology. The bow was not superceded until the invention of black powder by the chinese in tenth century. The chinese used black powder also known as gun powder in fireworks and then handcannons which first propelled stones. This is when the firearm was born.Firearms have dominated the battlefield and indirectly society today because of thier use. They started out as chinese hand cannons, then a stock and sights were added to make the first muzzleloading firearms. The musket was probably the most famous among these. Rifling was then added to the guns, along the invention of the conical shaped bullet which replaced the sphere previousuly shot. Both of these projectiles were still a solid lead slug. If you were to combine all of these components but add
Topic Description:
Projectiles can be anything. This includes rocks, pieces of wood, natural, synthetic, anything that is thrown, shot, slung, propelled, dropped, or anything else that has a single force acting on it. This could include a bowling ball dropped off a building, an arrow shot out of a bow, a bullet shot out a gun, a baseball thrown during a game, the most well known is probably the bullet. This could also include a rocket, a marble slung out a sling shot, the list is endless.
All in all, the most common projectile would be the bullet fired from a firearm. It is a great example of gravity and the force acting on it. Once the bullet leaves the muzzle of the gun the only force acting on it would be gravity. The force of the propellant burning, not exploding, forces the bullet from its resting point which is usually in its cartridge, although it does not need a cartridge. Upon leaving the muzzle it becomes a projectile and has the momentum of the burning propellant's gases stil but is now only under the force of gravity. This is why you can have a level barrel, and upon firing the gun, drop a bullet the same weight and size of the one fired and the two bullets will impact the ground at exactly the same time.
bullet_from_revolver_1.jpg
References
http://en.wikipedia.org/wiki/Bow_and_arrow
http://inventors.about.com/od/estartinventions/a/explosives.htm
http://blog.seattlepi.com/art/2008/05/29/bullet-in-the-brain/

This page was created by Caleb Bratton for Physical Science with L. Craig