Archimedes’ Principle

→ It states, when a body is immersed fully or partially in a fluid, it experiences a upward force

equal to the weight of the fluid displaced by it.

Applications of Archimedes’ Principle

i) It is used in determining relative density of substances.

(ii) It is used in designing ships and submarines.

(iii) Hydrometers and lactometers are made on this principle.


→ It is because of this ship made of iron and steel floats in water whereas a small piece of iron

in it.

Relative density

→ The ratio of the density of a substance to that of the density of water is called relative density.

• Relative density = Density of a substance/Density of water

→ It has no unit as it is a ratio.