Question

Which property of liquid is responsible for the spherical shape of liquid drops?

Answer 1

Hint: Out of all three dimensional shapes, the sphere is the shape that has the minimum surface area having the same volume when it touches the surface. This plays an important role in answering this question.

Complete step by step solution:
Surface tension is defined as the property of the surface of liquid that allows it to resist an external force. It is tension of surface film of a liquid caused by attraction of the particles in the surface layer by bulk of the liquid. It tends to minimize the surface area. In case of liquids attractive force of surface tension causes drops to take spherical shape. Because the sphere has the smallest surface area and surface tension tends to minimize the surface area. Due to this reason the shape of liquid drop is spherical.

Additional information: We can see many phenomena of surface tension in our daily life such as sticking rain drops on windows, a ring of clear liquid near the top of the inside rim of a glass of wine, insects walking on water, floating needles on the surface of water. Surface tension mainly depends upon the forces of attraction between the particles within the given liquid. It also depends upon the gas, solid or liquid which is in contact with it. Energy responsible for the phenomenon of surface tension may be thought as approximately equal to work or energy which is required to remove the surface layer of molecules in the unit area.

Note: It seems that gravity, air resistance could be the answer, but remember surface tension is the only answer to this question. Surface tension produced by cohesion makes it possible for light objects to float on water without sinking.