The question I chose to investigate in week 2 of the course was “Which pendulum will come to rest more quickly—a lighter pendulum or heavier pendulum? The procedure I designed was:
1. Cut a piece of string 30cm
2. Tie a large washer to the string
3. Using a push pin secure the string to a piece of card board
4. Lift the string to one of the sides so that it is perpendicular to the pin and hold it
5. Start a stop watch as you release the washer
6. Record how long it takes for the washer to stop
7. Repeat steps 4-6 an additional five times
8. Remove the large washer and Repeat steps 2- 7 using a small washer
The results were as I expected given pendulum with the lighter mass took longer to stop meaning it had more acceleration. Although they are released with the same force the
A= F/m, the larger the mass the slower the acceleration. To obtain a different result instead of a washer I would use an object with a different shape such as a flat piece of wood and tie it so the surface area could play a part. I believe giving the object with less mass a larger surface area would change the outcome of this experiment.
Using the pushpin was not as successful as I thought; I ended up having to repair the pushpin hole with tape several times.
I would use this experiment with my students but if my idea of using the wood to add the effect of air resistance, I would make them run it with the two types of material. I would do this without introducing air resistance in my lecture hoping they would discover it on their own.
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