This was a project that my substitute started with my students right before I got back. It was so much fun. She introduced the lesson by showing them the video on this link, (TOTALLY worth watching!!) and then set them loose. When I got back, we fine tuned the drawings and then learned how to shade spheres to add a little more interest to their drawings. They we so great at shading the spheres. I never remember being able to do it this well when I was that old. Way to go kids!
This is the example I showed them to make sure they understood that each sphere needed to be shaded using the same light source.