How can a egg float with salt water?
Adding salt to the water makes it more dense (heavier per unit volume). So now the egg has to push a smaller volume of the salt water out of the way before it pushes it’s own weight in water out of the way. The egg will float to a level where the same weight of water is displaced by the egg. Then when gravity tries to push the egg under more, gravity will also push the water down, which will in turn push the egg back up until the amount of water displaced weighs less than the egg. It’ll kind of bob there (even microscopically) until you pull it out.
