Not all topics in physics are
as hierarchically structured as projectile and orbital motion. As described in the previous paragraph, each
concept builds on prior understanding. If students have misconceptions about Newton’s first law, they will
not be able to grasp projectile motion. If students don’t understand projectile motion, they should not
begin to study orbits. Therefore, instruction on these topics should have diagnostic questions and activities
built into them so that the teacher can continually monitor students’ understanding and make midcourse
corrections whenever necessary.