Seeking to derive the formula for the volume of a square pyramid, geometry learners construct six square based pyramids that, when pieced together properly, form a cube. Two short videos demonstrate the relationship...

Contains six examples of polyhedra nets (cube, tetrahedron, octahedron, dodecahedron, icosahedron, cubosctahedron).

Very deep presentation of molecular bonding and orbital theory. Nice graphics and text make it a good presentation of some high end material.