The sphere is perfect as a classroom exercise because there is no way of faking it! If you make one of the transition tones in the light even a little bit too dark it will look like a spot or blemish. Make the value too light in the dark range and the form doesn't turn. The more one works on it and the more real looking it becomes, the more delicate your handling must become or it will stand out compared to the previously painted passages.
Jessica Du painted this during the Sunday drawing and painting class. She is in high school and works very consistently here, even though she has the usual full high school schedule. This is all going into her college portfolio I am completely impressed at her level of focus and the care she puts into her studies. At that age, I had nowhere near her level of maturity or quality of finished work.
