Video: Why do the Atlantic and Pacific oceans not mix? (One Minute Explore, 2021)

While we’ve given our planet’s oceans separate names, in reality there’s no border between them, and currents continually flow between them and mix their waters. The border between the Pacific and Atlantic oceans is like a line between two worlds. It looks as if the two oceans meet at an invisible wall which does not let them flow into each other and mix their waters.  

• Why does it happen? Based on watching the video, describe this phenomenon in your own words.