[Blaugust] Wooden Dice

I missed yesterday, so I want to do two posts today. This afternoon I decided to finish up a wood project for my class that I thought would be quick. I only really had to drill the holes (dots) for my wooden dice and I was finished with them[1].

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Well, I already had 2 dice done, and wanted 2 for each table (7 tables in my room). With 1 extra die “just in case”, that means I needed 13 dice. I didn’t think of this until afterwards, but there are 21 dots per die, so that’s 273 holes I had to drill.

It took a few hours.

This was scrap wood left from some benches that I made for my wife. The extra pieces were already down to 1.5″ x 1.5″ x 3″ chunks, so I only needed to cut those in half to make cubes that were 1.5″ on a side. I used a jig saw for that and a 1/8 inch drill bit to drill the holes.

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Here’s the setup. Just getting started. See the die I’m currently drilling on the right?

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A few more done.

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Finally done!

I’m not sure what I’ll use the dice for, but it’s always handy to have some dice around in a math classroom. Hopefully students will find these cooler than your average die[2].

Some tips for making the dice

I used a wood file to soften the edges. Some are clearly not cubes, but they’re close enough to real dice for my purposes: an 8th grade math classroom[3].

Drilling the holes and making the sides look good is the hardest part. I eventually settled on a pattern of lightly tracing the diagonals of most sides out with a pencil (2, 3, 4, and 5). The 6 I just measured out two center holes and eyeballed it for the other four on that side. I saved the 1 for last on every die because it was easiest to just drill.

One cool thing is that the center dot/hole on the 1, 3, and 5 all connect in the very center of the die because I drilled that hole deep enough. But because of the “opposite sides have to add to 7” rule, you can’t see straight through the whole die, so each hole is orthogonal to the other two!

 

[1] I should probably still sand them down so students don’t get splinters and sue me. Hmmm.

[2] But not so cool that they’ll want to take them home.

[3] If a student complains that they’re “rigged”, I’ll ask them to prove it and *voila* I’ve got a great lesson on probability and testing setup.

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2 Comments

Filed under Teaching

2 responses to “[Blaugust] Wooden Dice

  1. This is seriously ripe for some statistics / probability investigations since the dice are not perfect! Check out this one: https://mathcoachblog.com/2015/03/29/statistics-arts-and-crafts/

    Obviously with eighth graders you would not calculate chi square, but you could have every student roll one wooden die and one known fair die 100 times, calculate the average and make dotplotd, and have a conversation about how far the average has to be from 3.5 ( the expected average) or how different the shape has to be from uniform before you can reasonably suspect the die is unfair. This introduces the idea of statistical significance without worrying about numbers.

    • That’s so cool! That’s kinda what I was thinking of, but not nearly so polished. That’ll be a great resource once/if the students start complaining about “fairness of the dice”.

      Thanks a bunch!!

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