# Day 118: Circuit Sim Again & Earth’s Layers

AP Physics: Circuit Sim Again

Students used PhET’s circuit construction kit to explore Kirchoff’s Laws in series and parallel circuits. I also tried to mimic an extension of an electric field mapping lab by having students place the ground probe of the voltmeter at different points in the circuit, then move the measuring probe around the circuit. I liked that this got students noticing that the total change in voltage is always the same and it got them thinking about what a negative voltage means. On the Kirchoff’s Laws portion of the activity, I saw a lot more variation in how students thought about the patterns than in the past, which was a lot of fun. I was especially impressed when one student pretty much derived the equivalent resistance for a parallel circuit.

Earth Science: Earth’s Layers

Today, we built on the scale diagrams students made yesterday, adding some information on the properties of each layer. I tried to get some deeper thinking by asking questions like how two layers could have similar composition, but different densities, and it was a little tougher than I expected. I think if I’d primed students with some questions about pressure, that task may have been easier. It bothered me to just state give students information about the interior of the Earth, so I spent a few minutes talking about seismic tomography with my students. Next time I teach the course, I’d love to come up with a lesson to give students an analogous experience.