Interactive 3D shapes and nets for the whiteboard

What the interactive 3D shape tool does on screen

It puts one solid in the middle of the whiteboard, big, and lets the class turn it, mark it and open it out. The shape spins slowly on its own until somebody touches it, which is enough to get a Year 1 class watching before you have said anything.

• The ten shapes. Listed down the left: cube, cuboid, triangular prism, pentagonal prism, hexagonal prism, square pyramid, tetrahedron, octahedron, dodecahedron and icosahedron. Tap a name and that solid takes over the board.
• Spinning it. Drag left and right to go round the shape, up and down to look over the top of it or underneath. A finger works on a touchscreen, a mouse works on a laptop.
• Corners, Edges and Faces. Three buttons in the control row decide what you are counting. Corners puts a dot on every vertex, Edges lays a rod along every edge, Faces leaves the flat panels themselves.
• Tap to mark. Tap a corner, an edge or a face and it turns red, and the running total sits in the black tag above the shape list. Tap it again to take the mark off, or press Reset marks to clear all three at once.
• See-through. On to start with, so the faces are half transparent and you can reach the corners and edges round the back without spinning the shape away from what you are counting. Turn it off for a solid, opaque look.
• The net. The slider along the bottom runs from Solid to Net. Drag it and the faces hinge open along the black lines where they meet, smoothly, and it holds at whatever point you let go.
• What the fold hides. Corner dots and edge rods only appear on the closed solid, so they vanish the moment the fold starts. Faces stay tappable the whole way, and the marks are kept, so a face marked red on the solid is still red when it lands flat in the net.

How to use it in a lesson

Start closed, on Faces, with See-through on, and do one thing at a time. The shape is the lesson, so resist showing off the net in the first minute.

1. Ask before anybody taps. How many faces does this cube have? Take two or three answers and write them up. Somebody will say three, because that is how many you can see, and that disagreement is worth more than the right answer.
2. Send one child out to tap them. The class counts along with the tally. When a face has already been counted it is red, so the argument about whether that one was done is over before it starts.
3. Switch to Edges, then Corners, on the same shape, and write the three numbers on the board beside each other. Do two prisms and the pattern starts arriving without you pointing at it.
4. Guess the net. Ask everybody to sketch what they think the shape will look like opened out, then move the slider slowly. Stopping at halfway is the useful bit, not the end.
5. Park it part folded and leave it there while you talk. Half open is where most children finally see that the flat thing and the solid thing are the same object.
6. Sort them. Work along the list and split the prisms from the pyramids. What has to be true of a prism, and does a cube qualify? Print the board if you want it on paper afterwards.

Ideas by year group

• Year 1. Cube, See-through off, Faces. What shape is each face? Spin it and check they really are all the same.
• Year 2. Cube and cuboid side by side across two goes. Count the faces on both and ask what is different about them, and what is the same.
• Year 3. Square pyramid, then triangular prism. Count the faces on each, then decide which is the pyramid and which is the prism, and say how you knew.
• Year 4. Hexagonal prism with the slider halfway. How many rectangles will the net have, and what will be at the two ends?
• Year 5. Octahedron on Edges with See-through on. Twelve is a lot to count in the air, so mark them, and then predict the tetrahedron before you count it.
• Year 6. Fill in faces, edges and corners for five or six of the solids and hunt for the rule. Faces plus corners is two more than edges, on all ten of them.

The misconceptions it helps with

A shape has as many faces as you can see. Three on a cube, four on a pyramid. Turning See-through on, or spinning the solid while the red marks stay where they were put, fixes it faster than any explanation.

Double counting, and losing count. Counting round a solid in the air goes wrong for nearly everybody past about eight. The marks stay red, so the class can always see which ones are done.

Corners, edges and faces get muddled. Switching between the three modes shows a dot, a rod and a panel on the very same shape, which separates the three words far better than three definitions do.

Anything with a point is a pyramid. Put the square pyramid next to the tetrahedron and the prisms and the class has something to argue about instead of a rule to recite.

Frequently asked questions