Two bodies of water meet, but do not mix with each other due to a limit. How can this happen? Usually, when water from two seas meet, it is suspected that the water will mix with the temperature and the salt concentration tends to be balanced. However, the reality is different than expected. And for example, although the Mediterranean and the Atlantic Ocean, as well as the Red Sea and Indian Ocean are physically meeting each other, the water does not mix. This is because between them there is a limit. This limit is a force called "surface tension".
This is the power of god that no man can do perfectly like this.