The question I chose was which pendulum will come to rest more quickly a lighter or heavier pendulum? I created a test using the materials from the science kit from Walden materials. The materials include three washers of varying masses, nylon string one meter in length, one broom handle, two chairs, data table, and stopwatch. I created a data table to record findings and used a stopwatch to determine the period for each pendulum in motion. I began by placing the broom handle balanced between two chairs, a string 17 centimeters long tied to the broom handle in the middle and a washer tied to the other to create the pendulum. I raised the washer to 22 centimeters high and let it swing. I used a stopwatch to time the movement of the different washers. I tried the experiment with three different mass washers, and tried the experiment three times for each washer. I recorded each washer’s movement time. To my surprise, the washer with the least mass came to rest quickest. This required me to do a bit more research in my book. I thought the mass had to be part of the missing link for me. I found force equals mass times acceleration, but could not understand how gravitational pull had not stopped the larger mass quicker. Then upon reading over the second law of motion, I found that inertia was the factor I had not accounted for in my hypothesis, “The greater the mass the greater the resistance to change in velocity” (Tillery, Enger, and Ross, 2008 p. 41). What I discovered was that the more mass something has the more force it takes to move it. However, it also takes more force to stop its momentum, which was the answer to why it takes the washer with more mass longer to stop its momentum. As I realized I was trying to use the wrong equation, I discovered the momentum equals mass times velocity or p=mv; therefore, the answer makes perfect since that the washer with more mass will stay in motion longer because it has more momentum” (Tillery, Enger, and Ross, 2008 p. 43).
The experiment went well as a whole. I think it is simple enough for students to get the understanding. The only problem with the experiment is getting the string the same length every time you change the washers. It is difficult to perform the experiment by oneself, so I would use partners.
Since I learned much from the experiment and had little difficulty the set up and performance of the task I would not make any changes. I would have to explore if I needed to give more instructions to my students. I came up with the experiment; therefore, I am not sure if the students would devise a different plan. I would try it and then revise accordingly. Since I teach Life Science and very little physics, I would have to try it with students before I could make specific changes.I would set this experiment up using the internet site from this week’s resource by having students predict what the outcome of the swinging motion results from different lengths of a mass. I would also have students do some reading about inertia and momentum. These are particular helpful in this assignment.
An area this affects students personally is potential energy changed to kinetic energy. They could transfer knowledge that even though once the washer is let go and there is kinetic energy it lessens with each swing. We would discuss why one should not step out in front of a child that is swinging. We could discuss what size child the student might be able to stop swinging without being hurt. Then students could develop a model of a ride in an amusement park that used the energy from a pendulum motion.