When water is confined in tubes of very small bore, the forces of cohesion (the attraction between water molecules) are so great that the strength of a column of water compares with the strength of a steel wire of the same diameter.

• 当水被限制在内径很小的管道中时，内聚压力(水分子之间的相互吸引力)是如此之大以致一支水柱的强度相当于一根直径相同的钢丝的强度。