Learning goals: Teacher Facing Calculate the volume of a sphere, cylinder, and cone which have a radius of $r$ and height of $2r$, and explain (orally) the relationship between their volumes. Create an equation to represent the volume of a sphere as a function of its radius, and explain (orally and in writing) the reasoning. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 8.5 Functions and Volume, Grade 8.