The exercise may also be modified to meet the needs of your students. You may choose simply to grow alum crystals and observe the shapes. You may modify part two of the experiment by placing a jar in a cooler of warm water to slow cooling further. You may try mixing solutions of salt and alum to see what sorts of crystals are formed and whether the crystals will segregate or grow together. Apparatus for growing crystals.
Seed crystal is suspended by thread from a pencil placed across the top of a jar or beaker.
Approximate shapes of alum crystals.