A combination of math and art, this annual 6th grade project intrigues everybody. We began making them when my 22 year old son was in 5th grade, and for an enrichment class he researched math puzzles and games. His interest in them waned many years ago, but I've been intrigued ever since, and so have the kids. First we break down the word: tri = 3, so it has 3 sides, or 'faces'. Then hex = 6, and it has 6 edges. Then of course flex = bend, so we have a 3-faced, 6-sided, flexible polygon! Then, an added bonus, each face has an additional 'rotation'. What you see above is the first side, and its rotation.
Above is side 2 and its rotation, and below you see it being flexed, or rotated. The final step would be to reach into the center and 'bloom' it like a flower.
And below is side 3 and its rotation, still being colored (by one of the Sarahs).
It all starts with a sheet of bristol or tagboard, 3-1/2" x 22", measured into triangles. Accurate measurement is critical, so it is a good exercise for these kids. Then they learn to score the paper for it to fold cleanly. It's easy to do with good instruction, but hard for me to explain here on the blog. Here's a video of one: http://video.google.com/videoplay?docid=5757289930789567532#
***************The story of the origin of the flexagon is really interesting and fun. If you type "flexagon" into google, or even "trihexaflexagon", you'll find endless information on how to make them, and much more. (The trihexaflexagon is only one of many flexagons, but easy enough for kids to put together. We also make a tetratetraflexagon,which is even easier to make, but a little less dynamic a result.)
*************I've taught workshops on making flexagons at my NY state art teachers' conference, and may teach one again next year, so if you are in NY and are interested, I'll see you in Westchester in November! It's much easier to learn hands-on than from printed instructions, believe me!!
----------------------If you've read this far, you're in luck, because..Ta Da!! Here's a scan of my instructions that I used for my workshop! Feel free to copy and use them: