This project was focused on building a machine that would be able to launch a strong projectile. We had the option to build either a catapult, a ballista, or a trebuchet. My partner, Sara, and I chose to build a catapult. Our catapult needed to launch a marshmallow. One type of launch with the marshmallow would be for distance, as large as possible, and the other type of launch would be for accuracy, so that we could shoot the marshmallow into a bucket. This project applies to the study of technology because we formulated and built a machine that would perform a specific purpose.
One technological concept associated with this catapult project is force. The more force we pulled on the launching arm with, the more force it applied to the marshmallow. The large force allowed for marshmallow to have increased speed in the air and increased distance of travel. We were able to reach the farthest distance of 23 feet. Our other goal was for good accuracy, and by changing (raising or lowering) the amount of force we applied on the launching arm, we could change the distance the marshmallow needed to go to get into the bucket. Also, we adjusted the aim of the projectile by shifting the launching arm from left to right.
Learning Goals:
Our goal for this project was to figure out the most practical ways for the different parts of the catapult to be put together. There are several different ways the launching arm, rubber bands, and other pieces can interact, but we wanted to learn how to build a strong catapult. Neither my partner nor I had ever built a catapult or a wooden project like this before, so we hoped to figure out the ways that good catapults work.
Description of Our Project:
Our project was held together by a wooden pole that went through the side blocks and the launching arm. The arm was able to be pulled back and launch forward when released because of four rubber bands which were strung around two nails on the side blocks and two nails on the back of the arm. We placed a wooden bar across the whole machine, and its purpose was to stop the launching arm's motion after it was released. At first, after several test launches, we discovered that the launching arm was stopping too late to allow the marshmallow to go very far. We moved the wooden bar down further, and that allowed for the arm to stop closer to a 45 degree angle when launching. We know that a 45 degree angle allows for the farthest projectile distance.
Positive Feedback:
The catapult held up very well in terms of distance and speed of the marshmallow launches. It did so probably because it was a very sturdy machine, and the four rubber bands and our own arms that pulled the arm allowed for it to move with great force. These construction and testing elements performed well. The design element that we were proud of was the wooden bar that helped the arm to launch the marshmallow at almost 45 degrees.
Redesign Paragraph:
If we were to do this project again, we could have figured out an even stronger way to use the rubber bands so that the marshmallow could be launched further. Also, we could change the overall design of the catapult so that it could launch the marshmallow not only far but higher up into the air. This would allow for the marshmallow to fall into the bucket more easily. One way we could do this is by adjusting the machine so that the wooden bar could be placed even further down.
Technological Resources:
I never realized that Elmer's glue is strong enough to hold a wooden machine, like our catapult, together. This was quite convenient, as there were many parts we had to glue together. Also, the wooden pieces we were able to choose from varied in thickness and in length, and that was very convenient because we did not have to cut and carve many pieces of wood. The only big machine we used was the chop saw, which we cut the biggest, thickest blocks of wood with. For the thin pieces of wood, we used a simple hand saw. The convenience of the technological resources allowed for us to put more focus into the design of the catapult rather than laborious construction.
Biggest Challenge:
The biggest challenge for us was the design process. We did not have much experience with catapults at all, so it was hard to even think of one design, let alone several designs. Eventually, we were able to put a plan together, and we even redesigned parts as we went along, like the rubber band placement. And although our catapult design may have seemed quite simple, it was effective, and effectiveness in distance and accuracy was the main goal.
What We Learned:
All in all, we learned how catapults actually work. In order to launch with strength and a good projectile, they require strong elastic components (we used rubber bands), sturdy materials, and a specific launch angle. The only type of catapult we were familiar with before this project was a simple plastic spoon. From our struggles of designing it, to our epiphanies while building it, all the parts of our catapult came together and we felt successful and more knowledgeable about catapults and projectiles in the end.
