"He has let loose the two seas, converging together, with a barrier between them they do not break through."
Surah 55: Ayah 19-20)

This property of the seas, that is, that they meet and yet do not intermix, has only very recently been discovered by oceanographers. Because of the physical force called "surface tension," the waters of neighbouring seas do not mix. Caused by the difference in the density of their waters, surface tension prevents them from mingling with one another, just as if a thin wall were between them.


It is interesting that, during a period when there was little knowledge of physics, and of surface tension, or oceanography, this truth was revealed in the Qur'an.