DO IT BETTER Project
The "Do it Better" project, is somewhat of a unique project. Our task was to look back on a project that we did earlier in the year, and do it better (hence the name). We could choose from any project, or, if we didn't want to redo a project, we could build a chair made entirely out of cardboard. My group's decision was to build a catapult.
Earlier this year, a bunch of 8th graders shadowed the school, and were put into groups with us. Our teacher assigned us a task to do with the 8th graders: our goal was to build a catapult that could launch a tennis ball as far as we possibly could, and a human could not be a power source. Since at the time, we only had 30 minutes to complete our catapult, we didn't do a very solid job (which was to be expected). However, my group and I wanted to see what we could make in a whole week and a half. Our design was essentially a Roman ballista. The ballista kind of resembles a crossbow. Our ballista would be powered entirely by rope. We had a half pipe that the ball would travel through, and a rope attached to a pad, and we would pull the pad back and set it behind the ball. Pulling back the rope gave it a ton of tension, translating to a ton of power. Some of the physics concepts that we used were force, velocity, acceleration and momentum. Force = mass times acceleration is Newton's second law. If we apply a lot of force, to a small mass, we will be able to get a lot of acceleration, which would make the object go much farther. Velocity = distance divided by time. Having a high velocity (speed), translates to a greater launch distance, and that is our whole goal, so the more velocity we can get the object to have, the farther the object will travel. Momentum = mass times velocity. If we can get the object to have a greater momentum, it will cut through the air better, and overcome air resistance, which will help it go farther. The design, and thought that went into the project was perfectly executed, and the result looked nice, but it didn't perform well. We were not able to get the ball to go as far as we had hoped. This is probably because of 2 reasons: 1, the rope is moving too fast to solidly catch the ball, so it kind of just brushes over the ball. 2, The ball has to overcome too much friction before leaving the ramp. This slows it down a lot, making it fall short of the expected distance. Our group didn't work very efficiently. Most of the tasks were 1 or 2 person tasks, leaving 1 or 2 other people sitting around, not contributing. There were times when as individuals, we worked really well, but we didn't work to well as a group. One thing that I could have done better, was I could have carried my weight a little more. Like I said, a lot of the jobs we had were for 2 people, and I was usually the one that didn't have anything to contribute. From the beginning, I should have taken more of an initiative, so that I would be involved all the way through the project. That is something that I will remember next year in biology. |