This short riddle asks: What is made of water but disappears when you put it in water?
The answer is: ice.
Ice is simply water in its frozen state. When you place an ice cube into liquid water, it begins to melt. As it melts, the solid piece gradually disappears and becomes part of the surrounding water.
The riddle works because the object is made from exactly the same substance that causes it to lose its visible shape. Nothing truly vanishes; the ice changes state from solid water back into liquid water.
That small scientific detail is what makes the answer satisfying. If you were thinking of something that dissolves, the clue “made of water” points you toward the frozen form instead.
