The sound of summer is ice cracking as you pour yourself a cold drink. Hearing that snap and pop cools everybody down. But why does ice crack? Periodic Videos explains the reason why ice straight from freezer suffers that sudden crack versus how ice left on a tray will just melt instead of crack.
The phenomenon is known as differential expansion. The drink is warmer than the ice so when an ice cube is dropped in, the outer core of the ice warms up and expands while the inner core of the ice remains cold and doesn't expand resulting in the crack. Part of the ice is trying to expand, part of the ice is trying to stay the same.