Step-by-step explanation:
When the student crushes sugar there there occurs an increase in the number of molecules or particles of sugar. This means that now more number of sugar particles (solute) are able to interact with water (solvent).
Therefore, there will be more number of collisions taking place between the solute and solvent molecules.
As a result, sugar will dissolve readily into water as there is an increase in interaction between solute and solvent particles.
Thus, we can conclude that when he crushes the sugar and then stirs it into the water then it will work as this leads to more interaction or collisions between the solute and solvent particles.