The bullet proof vest was invented by Stephanie Kwolek at the DuPont science company in 1966. While experimenting with high performance chemical compounds led to the development of the synthetic material called Kevlar. The first Kevlar material to hit the market in the early 1970's was called Kevlar 29 and from then on it was being improved, and by 1988 the second generation of Kevlar material was called Kevlar 129.
The way that a bullet proof vest works is that it is made up of different layers to absorb the shock of a bullet. So when a bullet hits a bullet proof vest the shock is absorbed and the energy from the shock of the bullet is distributed throughout the entire vest causing the bullet to mushroom. The reason for multiple layers in the vest is for added protection and more fabric and layers for the shock of the bullet to spread throughout all the layers in the vest. This also lessens the chance of trauma from the shock of the bullet, but there will still be a welt there for a while because even though the bullet's shock is lessened the force of the bullet will push the vest inward causing the skin to react the same way by pushing in, somewhat like a paintball.
Since the introduction of the bullet proof vest and its improvements over time, now the public can purchase bullet proof vests, I guess it provides some extra safety and protection in potential areas were some can be harmed. Even though the public can now purchase their own bullet proof vests but, they don't come cheap, usually a single layered standard Kevlar vest can cost someone as much as $500, though when you think about it, you cant put a price on the safety of you life.
The invention of the bullet proof vest has given the edge of bullet resistance inventors over the bullet designers yet it seems the bullet designers are usually ahead, for example, there is no vest that can protect someone against a 50cal. bullet. The invention of the bullet proof vest definitely affects the world, because most governments who can afford Kevlar vests for their officials, police, and military will purchase them. So the invention of Kevlar has given the world the security and protection that it has given the U.S, when Kevlar 29 was introduced to the military and police.
The bullet proof vest has gone under major improvements in the last thirty some years since its invention in the early seventy's. Some of the improvements that make it better and safer is the tighter weavings of Kevlar, making the weavings tighter is a very important improvement that greatly increases the safety of the vest while not increasing the cost to manufacture and sell it. Some of the designs of the vests and different materials can greatly increase the safety and versatility of the bullet proof vest, such as the experimental bullet proof vest named Dragon Skin. It is distinguished by its half-dollar sized circular discs that overlap like scale amour, creating a flexible vest that allows a greater range of motion and can absorb more hits than standard military body armor. The discs are composed of a silicon carbonized ceramics matrices and laminates, much like the larger ceramic plates in other types of bulletproof vests.
The basic type of scientific principle that makes this bullet proof vest work is the type of material that it is made out of, that I have talked about called Kevlar that stops the impact of the bullet and spreads the shock from it throughout the vest.
