Question

Why do liquids flow?

Answer 1

Hint: How loosely packed a molecule is depends upon the intermolecular attraction between the particles of a matter. More loosely packed a molecule is, more is the motion of particles of the molecule in random direction. This basic information can be used to find the reason behind the flow of liquid.

Complete step-by-step answer:
The particles in liquid are close to each other but have some intermolecular spacing between them which is less when compared to gases but more when compared to solids. As the particles in liquid have small between them, they have little force of attraction and thus, the particles are not tightly bound to each other. Now, as the particles have little spacing between them, the particles can be displaced or moved. Thus, the liquids flow.

Additional Information: We know, liquids flow from a higher level to a lower level. But, there are few fluids which flow from lower to higher level i.e. they climb up the walls of the vessel in which they are kept. Such fluids are known as Superfluid and this property of superfluid is known as Superfluidity. It is found in isotopes of helium namely Helium(III) and Helium (IV). These liquid forms of helium are liquefied by cooling till cryogenic temperature.

Note: Students must understand that the attraction between the particles of the liquid keeps the volume of the liquid constant. Movement of the particles causes the liquid to be a variable shape. Liquids flow and take the shape of the container but do not change its volume. Solids too are closely packed but it does not flow. Molecules in solids are tightly compressed and thus, solids just vibrate.