A hydrophobic property demonstrator (100) comprises an inclinable sample support (10) and an upper tank (20) for producing droplets (GA, GB) that fall onto a sample (A, B) placed on the support. The droplets are produced regularly with a constant size by selecting a profile and diameter of a hole (23, 24) at the bottom of the tank, and by maintaining a constant water level (N) in said tank. Such a demonstrator is particularly suited for demonstrating the efficiency of the hydrophobic behavior of spectacle lenses.