Buoyancy Law: the object immersed in the liquid is subject to upward buoyancy, and the buoyancy is equal to the gravity of the object to displace the liquid.

That is, f float = g row = m row g = ρ liquid GV row g row: drain the gravity of liquid

M row: drain the mass of liquid

ρ liquid: density of liquid

V row: drain the volume of liquid

(i.e. volume immersed in liquid)

If it is a solid iron block, it must sink. Because the ship's interior is empty, the ship's displacement in the water will be very large. When the gravity of the discharged water is equal to the weight of the ship, the ship will float

It's a matter of buoyancy, because steel is denser than water, and it's solid, so it sinks. However, the ship is not solid, and the volume of water discharged by it is much larger than that of steel used, so row g will be larger than material g, so the ship will not sink

This has something to do with the volume of the object

The same amount of steel

When the volume of an object is large and its density is small, it will float up,

When the volume is small and the density is high, it will sink

Ships are made of steel. The density of steel is higher than that of water. If it is solid, it will sink to the bottom of the water. But if it is hollow, its average density will be less than that of water, so that it will float on the water surface. 　　

Source: Jiangmen shipyard http://www.zhongyucy.com/