The Roman Empire was one of the first civilizations to use catapults in war and defense. They were used in many invasions and wars throughout the lifetime of the empire. Another society known to use catapults was China. They were also used in China for defense and war. One of the first catapults to exist was known as the gastraphete, and resembled a crossbow. This design required many people to help set it into place and required a lot of power to throw the item out of the catapult. The Greeks improved upon this design and created another type of catapult called the ballista. Instead of having many people trying to all set up the catapult at once, the Greeks added a crank at both sides so two people could set up the catapult while the rest fought off the invading army. These societies used catapults because of the distance and power they could output. A 20 pound rock could be hurled up to 200 feet away if an army was approaching from far. Catapults benefited these societies by fending off armies, which allowed the society and people to flourish.
Catapults are used in modern societies in many ways. They are still mainly used for war or defense purposes, but their usage within war and defense has changed drastically. In the past they were used for direct defense, but now they are mainly used with the aid of bombs and grenades. Before the invention of the airplane bombs and grenades were a huge portion of catapult warfare, but after the airplane was invented warfare switched to that. Catapults were still used however, because of the aircraft carrier. Aircraft carriers obviously cannot be long enough to hold a full-size runway, so catapults are used to speed up the aircraft takeoff.
Expanding on the aircraft carrier, which I think is the biggest modern use of the catapult, the US military uses aircraft carriers in almost all aspects of their operations. Although the ships have undergone numerous revisions and advances, they still cannot be built long enough to hold a full size runway. The catapult model that aircraft carriers use is the ballista model, which is one of the models we are considering for our catapult. This catapult works the same way as a slingshot. The plane is backed up onto the elastic wire, which builds tension. After the plane is ready to take off, the wire releases tension, shooting the plane into the air.
Another modern catapult use is in warfare. Grenades, bombs, and other dangerous devices can be thrown into a battlefield without any potential harm to the person throwing the item. It also allows for a farther range than a human can throw. These kinds of catapults, usually simple slingshots, are used in modern war. These slingshots are important advances in warfare technology, even if they are one of the simplest machines known to man. I don't think these slingshots are leaving our military anytime soon, unless something better is invented.
Catapult ideas we are thinking of for our project are the trebuchet and ballista models. From my research I think these are the most efficient besides an air cannon, which we cannot afford in our $125 budget. Our goal is to have the catapult with the longest distance while using minimal materials and trying to be eco friendly. I think we can achieve this by using a simpler and older catapult model (like a trebuchet or ballista) and trying to modify it to our personal preferences. I think using an older and simpler catapult model will also keep costs down and allow us to use more recycled materials.