Egg and Salt Water

An egg will generally sink in freshwater, but if we pour salt into the water and stir it, then the egg will start to float. The reason is that after salt is added, the density of water increases. However, the relationship between density and if the egg floats or sinks is not a direct causality.

Flat-Earthers claim that the phenomenon “proves” things fall because of density, and that gravity does not exist. In reality, the density of the water determines the magnitude of buoyancy the egg receives. If the buoyancy is higher than the weight of the egg, the egg will float, and vice versa.

A submerged object will receive a buoyant force with the same strength as the weight of the medium with the same volume as the object. The object will sink if its weight is less than the buoyancy it receives, and vice versa.

Both buoyancy and weight depend on the existence of gravity. Without a gravitational acceleration exerted by the Earth (or any other form of acceleration), there will be no buoyancy or weight. In a zero-g plane or when in orbit around Earth, for example, the egg will not float or sink.