Question

Why does the egg float half above and half below the water?

Answer 1

Have you ever wondered why some objects float in water and others sink? It has to do with the density of the objects compared with the density of the water surrounding them. If an object is less dense than the water around it, it will float. Because salt water is denser than freshwater, some things float more easily in the ocean—or extremely salty bodies of the water, such as the Dead Sea. 

Answer 2

Egg float half above and half below the surface of water because it is a young egg. As the egg becomes old it sinks to the bottom of the water vessel because as the egg ages, air enters the egg and the air cell becomes larger and this acts as a buoyancy factors which results in floating of egg. Usually fresh eggs will lie on the bottom of the bowl of water. Eggs that tilt so that the large end is up are older, and eggs that float are rotten.