# To and Fro We Go: Swingin’ and having a great time!

Today’s lesson focused on pendulums. The young scientists, in the beginning of class, spent some time thinking of pendulums they experience or have seen in every-day-life. We came up with an amazing list, which allowed us to appreciate how useful pendulums are to us. Their consistent and repetitive oscillation, or periodic motion allowed for the invention of clocks and the standardization of time, and they still have many uses in modern society. Specific examples include grandfather clock and the metronome. The time it takes the pendulum to make one full oscillation back and forth is called a period. The young scientists broke apart the parts of a pendulum and the parameters which contribute to it’s swinging motion: the mass, the length of the string, and the angle at which its released. We then used these parameters as variables to test which specific one actually contributes to the duration of the pendulum’s period.

Through a series of tests, as well as the young scientists’ analytical and math skills, we were able to conclude that the length of the pendulum determines the duration of the period, or the rate at which the pendulum swung back and forth! The other two parameters did not make a difference. Students learned that gravity works on different masses in the same way, so mass is not a factor in the period of the pendulum (unless, of course, we measure pendulums on different planets!). We then looked at two videos: one which demonstrated how length impacts the different swinging rates of pendulums and the other on how gravity impacts similarly sized objects in the same way, regardless of weight (ie, medicine ball versus a basketball). Ask your young scientist, which ball will hit the ground first?

To experiment with virtual pendulums at home, check out:

This video shows some of the cool patterns that a group of pendulum waves can make!