Creative Ice Cubes In A Tray

Cloudy ice cubes result when water is frozen quickly, or when the water is high in dissolved solids. When water is cooled to its freezing point, and ice starts to form, dissolved gases can no longer stay in solution and come out as microscopic bubbles. However, as ice floats in water, once there is enough ice to form a layer on the surface, the ice layer traps all bubbles within the ice cube. Commercial ice-makers use a flowing source of purified water to make ice with cooling elements at the bottom, allowing the bubbles to be washed away from the top as the cube grows.
Melting ice cubes sometimes precipitate white flakes, commonly known as "floaties". This is calcium carbonate which is present in many water supplies and is completely harmless.
Ice cubes can also be crushed or sheared into irregularly-shaped flakes, adding an interesting aesthetic effect to some cocktails. Crushed ice is also used when faster cooling is desired, since the rate of cooling is governed by the number and average radius of the ice particles.