Coca-chaos

The wobbling of a pop bottle is investigated by a molecular dynamics simula tion., and is shown to display chaotic behaviour. This is one of the simple st commonly available objects to show this behaviour, and is an excellent e xample for demonstrating the phenomenon. The reason for the chaotic motion is the fact that the bottle stands on five feet, the importance of this bei ng that the number of feet must be odd. The smoothness of the motion is int errupted whenever the bottle moves from one foot to another, but we show by considering a related "executive toy" that the chaotic behaviour is not a result of these motion discontinuities.