How to Improve the Collisions Lab

When an elastic collision occurs, there should be no loss of total kinetic energy and total momentum in principle. When students take the introductory mechanics lab in Physics 116 and 209A, however, Dr. Shi often notices that results vary greatly from one student group to another even if they are all following the same lab procedure to work on the same head-on elastic collision experiment. The loss of total kinetic energy is often as high as 30%. Our project is to understand what has caused such a big discrepancy between the theory and the experimental results. We have discovered that factors such as whether or not the track on which the collisions take place is clamped to the table, the friction between the moving carts and the track, and the distance between the photogates are all responsible for such a big discrepancy. The goal of this project is to revise the lab write-up to help the students better understand physics principles.

Throughout this semester this project has allowed me to gain experience in the mechanics part of the labs. Every week I had to assemble the equipment onto the track and test if everything was in good working order. There were times when I had difficulty such as the initial velocity of the cart not being consistent, the positions of two photogates being either too close or too far, and the capstone program not catching the data points. I would like to thank Dr. Shi and the Department for giving me this opportunity to gain more hands-on experience. After graduation, I plan to move back home to Monterey and get my teaching license. I would like to become a high school science teacher and give back help to the public school district that helped me get into college and show students that being a first generation college student is possible.