3D Shape Nets

Flat on the page, solid in the hand

A net is what a solid looks like unfolded. Cut it out, fold the creases, glue the tabs, and the flat pattern becomes a shape you can hold.

Four solids are available. A cube, six equal squares laid out as a cross. A cuboid, a box with three pairs of matching faces. A square pyramid, one square base and four triangles. A triangular prism, three rectangles closed off by two triangular ends.

Each net is scaled to fill the page, so the finished model is big enough for small hands to assemble without frustration.

Solid means cut, dashed means fold

The legend at the top of the sheet says so, and it is worth reading aloud to the class before anyone picks up scissors, because the single commonest failure is cutting along a fold line and turning a cube into six squares.

Cut the whole outline first, glue tabs included. Then score and fold every dashed line before any glue appears. Folding first is not a suggestion: pre-creased edges assemble squarely, and a model glued before folding ends up rounded at the corners and will not sit flat.

Tabs and labels, on or off

Glue tabs are on by default. Turn them off for older pupils and the net becomes noticeably harder to assemble, which is sometimes the point: working out where the tape has to go is itself a spatial problem.

Face labels are the other switch. On, they tell you what each face is. Off, you have a prediction task, and that is the better lesson: show a child a net and ask which solid it will make before they fold it. Most get the cube. Fewer get the prism.

What to do once it is built

Count the faces, then the edges, then the vertices, and write the three numbers down. Do that for all four solids and a pattern starts to show up that is worth noticing.

Then unfold one. Going back from the solid to the flat net is harder than going forwards and it is where the understanding actually lands. Print several shapes at once for a sorting task, or hand out nets with the labels hidden and let the room argue about which is which before anybody folds anything.