Imagine you were an arrow. If you tried to soar through the air on your own, you would no be successful. This is because gravity is pushing you down. Now, imagine an Native American hunter holding a bow, with you pulled back against the "bendy" string. Let's say the Native American hunter has two chances to shoot an animal. When the hunter seeks the perfect opportunity, he launches the "bendy" string back a short stretch and releases. Now, you are flying, but you did not quite reach the target. In his second chance, he pulls the "bendy" string at a long stretch, and releases. BULL'S EYE!!!!! This time the arrow flew a farther distance and was aimed at the right target. How did the Native American hunter's first trial differ from the second trial? The answer is the Elastic Potential Energy was stronger in the second trial than in the first, which impacted a farther fly of the arrow. Elastic Potential Energy is the amount of stretch of an object. In comparison, the Elastic Potential Energy of our "Soaring Straws" lab is the amount of stretch of the rubber band. In this case, the rubber band played the role of the manipulated variable, because its stretch was manipulated and changed. On the other hand, the gravitational potential energy is the height of which gravity is forcing an object to fall. Similarly, the lab suggests that the gravitational potential energy is the maximum height of the rocket in air. This is the responding variable because it is the reaction to the elastic measurement. We experienced a rocket launch, a take-off, and the power of gravity, The potential energy of the rocket turned to kinetic energy just as it was release from the "toilet roll" launcher. I've analyzed an intruiging relationship between the Elastic Potential Energy and Gravitational Potential Energy. I have observed that the more the stretch of the rubber band(EPE), the more the gravitational potential energy of the rocket. For example, when I was in the process of launching the rocket, I stretched the rubber band
1 cm back and the experiment resulted with an average GPE of 8.6 milijoules. In contrast, in the second trial, I stretched the rubber band 2 cm and the result was an average GPE of 19 milijoules.After these trials, I clearly was able to see a major difference and I realized the concept that the more the EPE, the more the GPE.
Even though our lab was very chronological, towards the end, our hypothesis was mistaken. Knowing that the rocket went to an average of .55 meters high with a 1 cm stretch in the 1st trial, and an average of 1.21 meters high at a 2 cm stretch, we believed that the 3 cm stretch of the rocket would prove more in the third trial. However, we predicted wrong, and a unique error occurred. Unexpectedly, the average of the height of the rocket of the third trial was 1.12 meters high. This surprised us because the average third trial height was less than the average second trial height. This impacted the gravitational potential energy of the third trial. In contrast to the first two trials, the GPE of the third trial was 17.6 millijoules. This data is proven in the graph. Some possible reasons why the third trial did not turn out as expected are maybe the thick rubber band was having a weak reaction to the 3 cm stretch that we pulled on it. Another possible reason is that my partner or I did not hold the rocket properly. Subsequently, maybe the rocket, after being released hit the inside of the "toilet roll" launcher. Next time, we can enhance the lab in various ways. For starters, we can use a different "less-stretchy" object to be used as the manipulated variable. Also,some input I can give is that the project will work more efficiently outside. This is because many times rockets were flying across the room, hitting other students, hitting the ceiling, and getting stuck on top of the ceiling lights. All these distractions can lead to inaccurate measurements. All in all, this lab was fascinating and educational.
