eli5: Why does adding salt increase the buoyancy of water?

Question

eli5: Why does adding salt increase the buoyancy of water?

In: Chemistry

Answer 1

You might have noticed that “lighter” objects (more precise: less dense objects) swim better than “heavier” objects, if both are in the same fluid. The reverse is also true: the same object will swim better in a heavier fluid (in technical terms: buoyancy results from a difference in density).

Saltwater is heavier than freshwater. Not so much you’d notice it when holding a glass full of it, but enough that you notice it when you try to dive with your lungs full of air.