We've already done more than usual
about cuboids, designing and making our fruit juice cartons, and then making them with cm cubes and using isometric and squared paper to represent others.
There were other things I would have done had time allowed. One is to create similar representations in pattern blocks, like those of Daniel Ruiz Aguilera, but simpler:
I've come up with another idea (after admiring lots of posts on Paula Beardell Krieg's
Playful Bookbinding and Paper Works blog, and after making popup chicks for Easter cards), that I think is a good one: popup cuboids.
I'm hoping that other people can also see that there's a cuboid outlined in the middle of the fold. It's a 3cm x 2cm x 6cm cuboid (albeit with top and bottom faces made of air). Here it is, made with the
NCTM isometric drawing tool:
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(I particularly like this cuboid, because it's central diagonal is a whole number. But that's not for my students.) |
So, if I decide there's no time this year, this can be a note to self as well as anyone else. Here's what I'll do.
I'll show another example with a
cube. Ask students to:
- make a smallish (< 8) cube out of interconnecting cm cubes;
- ask them to fold squared paper along a central line (scoring with scissors first might help);
- then make cuts away from that fold the size of the cube;
- score the new folds they need to make;
- fold in the cube;
- make annotations about how many squares there are on each face, what the total number of squares covering the cube would be and how many little cubes are needed to make this cube (lots of just-right calculations here).
Then I'd display the results with the cubes and next show a
cuboid like this and ask them whether it's possible to make a popup version of it. This is a little tricky because if all the dimensions are different you can't use that first central fold. Some experimentation would be essential. If someone finds the way - great! We'll go ahead and do roughly the same list of things I wrote for the cube.