Khan Academy
Khan Academy: Rotate 2 D Shapes in 3 D
Practice your 3D visualization skills by rotating 2D shapes. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
National Council of Teachers of Mathematics
Nctm: Illuminations: Volume of a Cube
"The volume of a cube can be developed by considering unit cubes, a single row (longs) of unit cubes or a single layer (flats) of cubes using this applet." This easy software makes it possible to easily construct a cube and take it...