Somebody told me that the Mediterranean sea doesn't have tides. That is truth?
Tides, like many of the phenomena in nature, are very complicated in their details. If the Earth and Moon were both perfectly spherical and the Earth was covered by an ocean of a constant depth, then everywhere the tides would have the same amplitude. However, the Earth has continents and islands and the oceans vary greatly in their depths. All of these things affect the amplitude of the tides seen in a given spot, as does the local climate and air pressure!
The Mediterranean sea does have tides, but they are of a very low amplitude, as you can see somewhat in the below diagram (from Legos via Aviso/Altimetry) where the Mediterranean is mostly shown in blue meaning its tides have an average amplitude of a few centimetres, (instead of the metre of so shown in the part of the atlantic you can see).
Figure shows the amplitude of predicted tides in centimetres from Legos via Aviso/Altimetry
The low tides in the Mediterranean are mostly associated with the fact that it has a very narrow outlet/inlet into the atlantic (although that is not the whole story).
This page was last updated on February 10, 2016.