Principles of Flotation

How does this fully Laden ship float on Water?

Logic : Steel is heavier than water. A Steel block sinks when it is dropped in water. So a ship made of steel must sink too.

Reality - This Steel ship although larger and heavier than the block floats. How can we explain this?. This lesson will answer  this question and enable you to  understand the principles of Flotation and Archimedes principle.

Archimedes principle : 

When a body is immersed in a fluid it displaces the fluid. The body experience and upward force called buoyancy. The downward pool due to the gravity is called weight.

Objects of equal volume experience equal buoyant forces. When a ball is immersed in water, it takes the place of volume of the water equal to its volume. Does the buoyant force on the body is equal to the the weight of the water displaced it.

Floating on the surface : 

If the weight of the body is less than the buoyancy when fully immersed, the body will float.

For an immersed body, if the density of the body is lesser than the density of the fluid the buoyant force is larger than the body weight according rises up till equilibrium is attained by reduction in immersed volume.

Immersed and Floating :

For an immersed body, if the density of the body is equal to the density of the fluid, the buoyant force is equal to the body weight. The body is in static equilibrium.

Sinking : 

If the weight of the body is greater than the buoyancy when fully immersed, the body will sink, for an immersed body, if the density of the body is greater than the density of the fluid, to gravity pulls the denser object down.

Why does ship floats?

A ship is designed to displace more water than its maximum displacement, hence it floats. A steel body sinks as the water it displaces is inadequate to support its weight.