Faces, Edges, and Corners of Solid Shapes

This idea walks around your house all day. Packers and builders think in faces and edges constantly when fitting boxes or joining beams. This is worth learning because naming the parts lets you describe a solid precisely to someone else.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Ask yourself where else the same idea might be hiding, then go and look.

This is a good thing for a young mathematician to know. Solids have parts with names. A face is a flat surface you could set on a table. An edge is where two faces meet in a line.

A corner, also called a vertex, is where edges come together in a point. A cube has six faces, twelve edges, and eight corners. Hold a box and count each part slowly, touching as you count so you do not count the same face twice.

Watch out for double counting faces. Set the object down, count the face touching the table first, then go around the sides, then the top. A fixed order stops you from counting one face twice. Do it carefully rather than quickly, and thank God for a mind that can learn.