### Geogebra 1

#### by jrosmith

It took me a while to think of something do simulate, and eventually I settled on making a variable force diagram for a pendulum. About 20 minutes into this, I decided that this was a terrible idea and set out to create a more interesting variable simulation. I stuck with the pendulum idea, but instead made a bar chart in geogebra.

This is modeled after the Energy Module in Pum, Lesson 3.4 specifically. Students are asked to reason as to how bar charts would change given different points in a bar charts motion. This simulation allows students to instantly check their reasoning.

Making the simulation was straightforward enough, from the get go I knew exactly what I wanted to accomplish. The hard part (unsurprisingly) was figuring out *how* to get geogebra to do what it was that I wanted it to do. You’ll have to forgive my work, as it is a bit messy, but lo and behold I accomplished my task.

A few notes: I made sure the pendulum bob was bound to the arc length cut out by my pivot point and two anchors, but for some reason it keeps going to a height of 1.01 instead of .98 on the right hand side. Because of this, the Kinetic Energy shows as (slightly) negative on that side. I’m not entirely sure why geogebra is allowing the bob to exceed it bounds on the right hand side, but seeing as this doesn’t really take away from the main point I’m not too worried about it. In addition, the simulation is not mobile, it is bound to the x-axis (technically it *is* mobile, but I wasn’t clever enough to design it such that all measurements are relative). For fun, I added two sliders: one for the mass of the bob and one for the value of the constant “g”. I imagine students will be able to have fun checking to see how messing with these values will affect the graphs.