This year I’m teaching my daughter physics, and though you might think it would be easy for a guy with a degree in physics to teach eighth-grade physics, it is not. It is undoubtedly easier than it would be if I didn’t have a degree in physics, but that’s not a high bar, you know? Much of physics beyond the most elementary observation is deeply mathematical; you need at least first-year algebra to make any sense of it, and at least a year of calculus to make a lot of sense. And to the extent that there are simple, practical, hands-on ways of exploring deep concepts, I didn’t learn them in college. So, for example, I did lots of fancy calculations of torque but never built a trebuchet, and I learned to analyze the role of a capacitor in a circuit but never built a Leyden jar. Teaching middle-school physics, then, has been an opportunity for me to fill in some rather distressing gaps in my own education, and to think about what I did learn in new ways.
To wit: In planning our unit on electricity and magnetism I stumbled across a book called Safe and Simple Electrical Experiments, by Rudolf F. Graf. Since it was published in 1960, “safe” assumes something slightly less than the helicopter parent’s standard of child care, and “simple” assumes a child whose brain has not been squeezed completely to mush by electronic devices: all the better! You have to think to do this stuff, and fiddle with things when they don’t work the first time, and there are delightful instructions on how you can give your friend an unpleasant but allegedly harmless shock. On the negative side, some of what were considered household objects in 1960, such as vinyl records, may not be as easily accessible in 2017. But there are nearly always substitutes if you hunt for them.
As our culminating project, we built a working telegraph. I will let Dear Daughter explain it herself. (Video after the jump.) Continue reading