Drawing Machines

Apparently we like things that involve math

It's Final Friday, kind of! We shifted this one around to accommodate a build schedule - because this month's activity took some serious planning on the part of Josh and Ashley. It's a build-your-own-spirograph-like contraption day!

You get some gears! And YOU get some gears!

Josh's previous life was in the watch-building world, where he spent a LOT of time thinking about gears. He designed this set of tools for us, set up a cutting template, and Ashley cut out each kit of parts on her laser cutter. (Big 👏👏👏 to both of them!)

Card Commitments
Two sets of hands helps.

Josh showed us how to assemble everything, and then we were off to the races: configuring, testing, and drawing lots of very shaky sprirograph-like designs. There was a lot of discussion figuring out how these can work, how the different gears interact, how odd, even, and prime gears interact, and how to predict the kinds of shapes the different gears will draw.

These are different and more complicated than the Spirograph toy, because you're not just tracing one gear around another. Those are technically epicycloids and hypocycloids. But you already knew that, right?

An epicycloid is when a fixed point on a circle rolls around the outside of another circle.
An hypocycloid is when a fixed point on a circle rolls around the inside of another circle.


But the drawing machines Josh created for us involve one gear moving around another, but ALSO with a movable arm extending to a THIRD gear, which ALSO has a drawing arm that can extend in other directions. If you point it back at the center of the big gear, you get a very spirograph-looking shape. But you can also make much weirder things! Does this have a cool 'cycloid' name? I don't know!

Will was the first to master the activity. Look at this beauty go:

Go Will Go