Something as simple as a pendulum can teach us so much. I hope that you will have the chance to see a Foucault pendulum. It is a mass on a long wire which swings back and forth. The beauty of this pendulum is that it demonstrates that the earth rotates. You can see that this is true because the path traced out by the pendulum changes very gradually. When set to swing in, say, the north–south direction, then over the course of the day it will end up swinging in the east–west direction. The only thing that has rotated is, of course, the earth!
Pushing your child on a swing is like driving a pendulum at its fundamental frequency.
Another pendulum, which you have surely come across, is located in your child’s playground. It is a swing. The cool thing about swings is that, like every other pendulum, if they have the same length they swing to the same beat. Whether you place a toddler or an adult on that swing, whether your feet fly high or low, the swing does not care. It keeps its own steady tempo, like an over-sized grandfather clock (or metronome).
And you, my dear fellow parent, can make use of this invariable tempo. How about pushing your differently weighted children side-by-side at the same tempo, one hand each? Talk about efficiency! How about telling your kids that ‘no, I can’t make you go faster unless I make the swing shorter’? How about… singing to the beat? Yes, you can sing them a song timed to their swings. You need to know some songs by heart to pull this one off. You’ll also need to experiment with which ones work best, but it can be done! This little game can keep everyone entertained. Just remember to go home before the earth has completed its daily rotation.