Question

Which do u think is the better way to produce large crystals from zinc sulfate-heating the evaporating dish until there is very little liquid left or leaving it to evaporate slowly?

Answer 1

Leaving it to cool and  evaporate slowly from the supersaturated solution of ZnSO4 is the better way to form larger and smoother crystals with a definite structure. A seed crystal can also be suspended in the solution to initiate crystallization.