water is in the solid state , called ice & ice cube is made of ice ->  ice cube is made of water in solid state  ice cube is made of water in solid state & water is a kind of liquid at room temperature ->  ice cubes have to be made by changing liquid water to solid ice  water is a kind of substance & freezing means a substance changes from a liquid into a solid by decreasing heat energy ->  water freezing means water changes from a liquid into a solid by decreasing heat energy  ice cubes have to be made by changing liquid water to solid ice & water freezing means water changes from a liquid into a solid by decreasing heat energy ->  ice cubes have to be made by freezing the liquid water  ice cubes have to be made by freezing the liquid water & freezing is a kind of exothermic process -> making ice cubes is a kind of exothermic process