For the guided inquiry activity, I investigated how the mass of a pendulum affects the time it takes to come to rest. I tested three washers of different masses by hanging them by a three foot string from a door frame. With the back of a chair as a reference point, I released each bob of the pendulum and recorded the time it took for the bob to become completely still.
When I first started this activity, I hypothesized that the bob with the greatest mass would take the longest time to come to rest. This was proved true through my investigation, but what I did not anticipate was the time it took for the bob with the greatest mass to stop. The average time for that bob was over thirteen minutes. I'm surprised I didn't hypnotize myself from staring at a swaying object for so long! :)
My experiment went very well. I did have to change the bearing of the pendulum from tape to a nail hammered into the door frame. The main problem I had with my experiment was the inability to calculate the velocity of the pendulum. Through my research, I discovered that the reason the pendulum with the greatest mass took the longest to come to rest was due to the fact that it had the greatest momentum. Momentum is simply the mass of an object multiplied by its velocity. Since I did not have the velocity, I could not factor this aspect. I did however use this website to compare the velocity of pendulums of various mass and found that if a pendulum is dropped from the same angle, various masses will always have the same velocity.
I could see myself exploring this same investigation with my students. I would however help my sixth graders design the experiment as a whole class since they have not had much practice creating a procedure. To help aid in their understanding, I think that a virtual pendulum like the one I explored would be a great supplement after the hands-on experiment. To pull in a connection to student's lives I could compare it to the pirate ship ride, like that from the resources from this week, or connect it to a person on a swing. We could even walk to the elementary school and use the swings to explore.
Hi Amanda,
ReplyDeleteWe did the same exeriment. It is funny that you had the same experiece that I had about the amount of time it took for the pendulum to come to a rest. I found this aspect of the experiment to be unrealistic for being able to conduct this experiment with three trials for each weight in a class period. After I did a little research on the subject I found this interactive at pbs.org. Here is the address: http://www.pbs.org/wgbh/nova/galileo/media/experiments.swf?which_exp=1
This site gave me the idea to shorten the lenght of the pendulum which signifigantlly shortened the time for it to come to a complete rest.
I too would use this investigation with my class of 8th graders. However, I would give them the opportunity to design the investigation because they would have had the opportunity to practice investigation since they are in 8th grade. I do think it is a great investigation for either grades being presented as structured inquiry or guided inquiry.
Hi Amanda,
ReplyDeleteI also teach 6th grade and I would use the whole class approach with the instructions. However, I would allow my students to perform this experiment in pairs. I also love your idea of using the virtual pendulum. This would also be a great way to incorporate technology in this experiment. This was a great experiment to use guided inquiry.