2. If salt is continuously added to clean water, the density of water will gradually increase and the buoyancy will gradually increase. When the specific gravity of water exceeds that of eggs, eggs will not sink to the bottom of the cup.
When the buoyancy reaches a certain level, the egg will float. Therefore, it can be concluded that the factors affecting buoyancy have a certain relationship with liquid density.
4. When the top interface of the floating body can't touch the liquid, only the upward pressure acting on the bottom interface will produce buoyancy. As for the object at the bottom of the container, this phenomenon is relatively rare, because as long as there is a thin liquid film between the two, the pressure can be transmitted, there is upward pressure at the bottom, and there is a pressure difference between the upper and lower surfaces of the object, and the object will be floated.