Latin is where we find the etymological origin of the term fluid. Specifically, it derives from the word "fluidus", which is the result of the sum of two components of said language:
-The verb "fluere", which can be translated as "flow" or "flow".
-The suffix «-ides», which is used to clearly indicate a visible quality.
The notion of fluid comes from the Latin word fluĭdus . The term, when linked to a substance, refers to whether it is in a gaseous or solid state .
Fluids move progressively from one place to another: that is, they flow . Due to their properties, fluids modify their shape without having forces that try to restore their previous shape.
The force of attraction that the constituent molecules of a fluid have is weak . In any case, the particles maintain their union thanks to this cohesive force and the walls of the container that contain them. A liquid, therefore, takes the shape of the container and retains its own volume, while a gas has neither its own shape nor volume.
It should be noted that all fluids have a certain degree of viscosity and compressibility . Temperature , pressure and density are other factors that determine its characteristics and behavior.
When the viscosity remains constant over time, the fluid is called a Newtonian fluid . An example of this kind of fluid is water . On the other hand, a non-Newtonian fluid has a viscosity whose value is inconstant, since it depends on temperature and other factors. Ketchup is a non-Newtonian fluid.
Likewise, we must not forget the existence of what is known as supercritical fluid. Specifically, this term refers to a substance that is in conditions of both temperature and pressure that are higher than its limits, which is known as the critical point .
Precisely those conditions in which said substance is found mean that it acts as if it were halfway between a gas and a liquid.
The supercritical fluid also responds to the acronym FSC, the transfer of matter in it is very favorable, its coefficient of thermal expansion is positive and even infinite, its isothermal compressibility is also framed as positive.
The liquids and gases that are generated inside the body, on the other hand, are called body fluids . Among them we can name blood , urine , sweat , semen and mucus .
A fluent language , finally, is one that develops in a simple and unhindered way. Something similar can be said about a fluid style : "I really liked the book since the author uses fluid language," "The filmmaker's fluid style is valued by viewers."
In the same way, we cannot ignore that it is also used to give shape to other terms. This would be the case, for example, of what is known as fluid therapy, which is a therapeutic measure that is used in the medical field and consists of the application of intravenous solutions to correct the alterations that exist in terms of hydroelectrolyte balance.