Question

Where do you observe Archimedes' principle in our daily life? Give two examples.

Answer 1

Hint: Archimedes’ principle states that, any object completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward or buoyant force. The magnitude of this force is equal to the weight of the fluid displaced by the body.

Complete step by step answer:
According to Archimedes’ principle, a body at rest in a fluid is acted upon by a force pushing upward called the buoyant force, which is equal to the weight of the fluid, that the body displaces. If the body is completely submerged, the volume of fluid displaced is equal to the volume of the body. If the body is only partially submerged, the volume of the fluid displaced is equal to the volume of the part of the body that is submerged.

Examples in our daily life:

1. On entering a bathtub filled with water, an equal quantity of water is displaced as the weight of the person.
2. A ship floats in the sea because of the buoyant force acting from the water. So that we can calculate the safe depth on its basis.

Additional Information:
Archimedes’ principle is useful in calculating the volume of an object having irregular shape. When the irregular shaped object submerged then the volume of the fluid displaced is equal to the volume of the object. It can also be used in calculating the relative density or specific gravity of an object.

For example, an object denser than water, the object can be weighed in air and then weighed when submerged in water. When the object is submerged, it weighs less because of the buoyant force pushing upward.

Note: Students should keep in mind that the mass of a body is a constant quantity, while the volume varies with temperature (and even with pressure for gas). So, the density also depends on temperature. However, the variation of density with temperature is usually small enough to be neglected. The density of water at $$4^{\circ }C$$is $$1000kg{m}^{-3}$$ or $$1gmc{m}^{-3}$$.