As a general rule, I don't like to let activities linger in a particular state. There are always subtle tweaks to make or the tough decision to cut something loose and try again. The advent of Chromebooks in my classroom has opened up a lot of opportunities we just didn't have before. Realized recently when it was time to talk about three dimensional vectors.
Historically, I turn the room into a giant coordinate system, we discuss how to orient ourselves in 3D space and I've had them build stuff out of straws. It was interesting at the time, though time consuming. Due to the nature of building things out of straws and electrical tape, the creations didn't last very long either.
Enter Tinkercad. I'd like to thank Autodesk for a monumental shift in the way they approach access to their software. Fifteen years ago, AutoCAD or the various things a college student might need were prohibitively expensive. It all came down to knowing the right person in the dorm who had license keys of a shifty nature. Since about 2010, they've done a total about face, making tons of great stuff available for free or cheap for students, teachers, or anyone who isn't a corporation. Tinkercad is a browser-based 3D modeling app that lets you mock up whatever you like. There are pre-built simple solids, and you can browse a whole library of community built objects and drop them into your design.
Rather than mess around with a bunch of straws and tape, I set my Pre-Cal kids loose on Tinkercad and gave them about 50 minutes to make something. The site's export options are intended for 3D printers, so we stuck with screenshots from a few different angles. We got some really awesome stuff.
Chromebook trackpads aren't the greatest, so this was a tad challenging for some. I do have touchscreen models, and kids with those were very happy with themselves. Wired mice can be had rather cheap in bulk, so that might be an idea for next year.