Hexaflexagons! Yet another awesome video from @vihartvihart:

So, now I know that hexaflexagons are awesome! On Vi Hart’s YouTube channel she describes herself as a professional mathemusician at KhanAcademy. Here’s the description of her latest video:

This video is based on a true story. Arthur H. Stone really did invent the hexaflexagon after playing with the paper strips he’d cut off his too-wide British paper, and really did start a flexagon committee (which we’ll hear more about in the next video). The details and dialogue, however, are my own invention.
More info coming soon, along with patterns. But in the mean time you can find instructions and printable patterns on other parts of the internet.

Follow Vi Hart on Twitter at @vihartvihart.

Making 3D structures in SketchUp and measuring surface area in 6th math

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I’m working with Catherine Hildebrandt on an activity that incorporates 3D printing into a 6th grade Geometry unit.

Catherine and her 6th graders were examining polygons, prisms, cylinders, spheres, surface area, and volume anyway. So, we thought we’d have kids design shapes, measure surface area and volume, and print out their creations on our Makerbot and Bits From Bytes 3D printers to pass around for their classmates to measure.

Catherine chose to use Google Sketchup for this project, as it is easy to construct an infinite out of shapes using the tool, and it is super easy to set the measurements/distance for lengths in the bottom right toolbox of the SketchUp window. I’d initially suggested Tinkercad, but for this project, I deferred to Catherine’s preference (especially after she spent quality time trying out each program).