Day 59: Electrostravaganza

Monday, Dec 11

Physics: We’ve whipped from some of the most complicated and unintuitive and challenging material in all of physics to… springs. Stuff stretches when you pull it. BOOM! It’s kind of a relief to everyone I think. Today they’re doing a classic Hooke’s Law lab stretching some strings with some slotted masses, plotting it with Excel, best fit, slope, the usual.


It’s nice to have something so utterly concrete and observable after freakin relativity. Also, something that I am not only 100% comfortable with but also really, really enjoy. The behaviors of solids, liquids, and gasses is super neat and has a lot of cool demos and activities. Also, HELIUM BALLOONS!

Honors Physics: We’re still doing waves, so today I started a deeper conversation about reflection and refraction. Introduced the Law of Reflection and Snell’s law, as well as wave front representations. The “roller skates from grass to concrete” metaphor was super duper helpful after the wave front discussion and how speed is directly proportional to wavelength because frequency remains constant. We walked through all the technical ideas, and they were working through it, but the roller skate story really, really solidified for them. I’d usually done that in the opposite order, starting with the roller skates, but this gave them something to hang the roller skate story on, which worked very well. We briefly spoke about curved mirrors but stopped short of doing ray diagrams, and refraction didn’t get to lenses. We’ll get there, of course, because one of the cool cosmology things is gravitational lensing, and we need to understand that to understand what we know about the universe, and we need to understand reflection to learn about telescopes. I’m so happy with this class.

AP Physics: I’m trying something new. Usually I go into electrostatics with a whole bunch of conceptual demos and moving charged objects around and charging and induction and polarizing, etc. etc. etc. This time I dropped RIGHT into the math of Coulomb’s law and within 20 minutes they were doing calculations to find the value of the electric field at a given point. These kids really crave math, and I want to get to potential energy and potential before break, at least having them use the equations, and then we’ll take it all apart with the usual demos and stuff once we get back. I want the math techniques processing in their brain while we’re gone, just so they have seen it all before, and I hope that will make it easier when we start needing to put all these ideas together. Fingers crossed!

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