Heat 150 ml. of water to boiling and add granulated sugar to the hot water until no more sugar will dissolve.
Tie a small weight to each end of several pieces of clean white string and suspend the strings in the sugar solution so that the weights almost reach the bottom.
Tie the free ends of the strings to a rod (such as a pencil) positioned across the top of the sugar/water container.
Set aside and leave undisturbed until the water evaporates and the sugar crystallizes on the strings.
Then enjoy your "rock candy".
