Distinction between solid ,liquid, gas and fluid.

Distinction between solid and liquid"

The molecules of a solid are usually closer together than those of a fluid, The attractive forces between the molecules of a solid are so large that a solid tends to retain its shape. this is often not the case for a fluid, where the attractive forces between the molecules are smaller. a perfect elastic solid will deform under load and, once the load is removed, will return to its original state, Some solids are plastic, These deform under the action of a sufficient load and deformation continues as long as a load is applied, providing the fabric doesn't rupture. Deformation ceases when the load is removed but the plastic solid doesn't return to its original state, The intermolecular cohesive forces in an exceedingly fluid aren't great enough to carry the varied elements of the fluid together( Hence a fluid will flow under the action of the slightest stress and flow will continue as long because the stress is present.

Distinction Between a Gas and a liquid"

A fluid could also be either a gas or a liquid, The molecules of a gas are much farther apart than those of a liquid. Hence a gas is extremely compressible, and when all external pressure is removed, it tends to expand indefinitely. A gas is therefore in equilibrium only if it's completely enclosed, A liquid is comparatively incompressible and if all pressure, except that of its own pressure, is removed, the cohesion between molecules holds them together, in order that the liquid doesn't expand indefinitely. Therefore a liquid may have a free surface, i.e., a surface from which all pressure is removed, except that of its own vapor. A vapor may be a gas whose temperature and pressure are such it's very near the liquid phase. Thus steam is taken into account a vapor because its state is generally shortly from that of water, A gas could also be defined as a highly super heated vapor, that is, it’s state is much far from the liquid phase, Thus air is taken into account a gas because its state is generally very aloof from that of air, the amount of a gas or vapor is greatly stricken by changes in pressure or temperature or both, it's usually necessary, therefore, to require account of changes in volume and temperature in handling gases or vapor, whenever significant temperature or physical change are involved in coping with vapors and gases, the topic is essentially captivated with heat phenomena ( thermodynamics ). Thus mechanics and thermodynamics are interrelated.

Published by Science tube 16 September 2020