Salinity describes how much dissolved salt is present relative to the amount of seawater. This model starts with a measured mass of salt and volume of water. It uses grams per litre for a simple concentration calculation, rather than pretending that this is identical to every formal oceanographic salinity scale.
Water and oceans · Discover & try
Why does evaporation leave the ocean’s salt behind?
Reading level 3 of 5 · IndependentChange
Word help
Salinity
The concentration of dissolved salts in water.
Dilution
A reduction in concentration when more solvent is added.
Dissolved
Mixed into a liquid at the molecular or ionic scale.
Watch · Try · Explain
See how it works
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Ideal well-mixed basin using grams per litre; no crystallization, overflow or full ocean chemistry.
What to look for
- Keep salt mass fixed while water changes.
- Compare evaporation with fresh-water addition.
- Read grams per litre separately from total grams.
Explain what you noticed
A new covered bowl contains 20 grams of dissolved salt in 2 litres of water. It gains 2 litres of fresh water without losing salt. What happens?
Keep this idea: Evaporation removes water while leaving most dissolved salt; rain adds fresh water and dilutes it.
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