In the scenes of Harry Potter and the Goblet of Fire where Harry is trying to understand the clue in the golden egg, the egg screeches whenever it is opened in air. When it is opened underwater, it emits a lovely song and the clue. If one assumes that the screeching represents faster production of sound, as running a tape player on fast forward, then the egg should actually be groaning in the air, as a tape player with a bad battery. Sound travels 4 times faster in water than in air, so to sound normal under water, the clue should sound SLOWER in the air.