It is a little hard for me to do some of these projects or investigations in my classroom due to the fact that I teach life science, and we are a standards based school. I have to follow the state standards in the classroom, but I try to do some of these investigations after school.
The question I selected for my guided inquiry lesson is: Which pendulum will come to rest more quickly—a lighter pendulum or heavier pendulum?
In this lesson, I made two pendulums using 18 inches of string tied to the shower curtain rod. On one I hung a one pound lead weight. On the other I hung a three ounce wood block. I pulled them back the same amount and let them go at the same time. The results are as follows:
Lead weight Wood block
Attempt 1 58 seconds 40 seconds
2 50 seconds 40 seconds
3 60 seconds 38 seconds
A heavy pendulum swings longer, but I don’t know why. A heavy weight does not fall faster than a light one when dropped, and surely gravity acts on the pendulum the same way. The fact that the pendulum is moving through an arc rather than straight down may have something to do with it. I tried to keep all the other variables the same-length of the string, letting them go at the same time, doing it in the same place so air currents or temperature wouldn’t affect the results.
This type of experience reinforces learning for students, and makes them remember the results much better than reading from the text. The issue I have in my classroom is that we can not breed fruit flies to study genetics, or go into the field to learn about ecosystems. We just do not have the resources. More than any other field, life science should be inquiry based, but I don’t know how to make that happen yet.
