Observe the level where the eggs are located in each recipient.
A vessel has water from the Mediterranean Sea, another from the Mar Menor and the third one water from the Baltic Sea. Eggs indicate the concentration of salts on each sea. The higher the salinity, the higher water density, hence a bigger buoyancy of the eggs.
The saline content of sea water depends on the primitive ocean’s composition and the later contributions of the Earth crust. Sea water composition is almost uniform but not its concentration. The Mediterranean, an almost closed and warm sea has a higher salinity than the ocean’s. Mar Menor salinity is slightly higher than the Mediterranean’s because its evaporation an water stagnation. Baltic Sea has a very low saline concentration, it has salty water but is fed by rivers that flow in and provide fresh water. It is a very closed sea, since its only exit is to the North Sea through a narrow channel.
«La salinidad en los mares» es un módulo de la Sala del Agua incluido dentro de la sección «Agua y ciencia»