Under most conditions, a liquid mixture does not have long-range structural order and may be considered to be a homogeneous collection of molecules in random motion. However, if a single-phase critical mixture of a partially miscible liquid--liquid system is subjected to a small temperature jump into the two-phase region, then structural coherence…

In the vicinity of a critical point, the impact of a substance's chemical identity is superseded by universal critical behavior for a number of physical properties, such as visible light scattering. In this classroom demonstration, students observe a single-phase critical mixture of partially miscible isobutyric acid + water (IAW) as the…