A liquid is a body with constant volume whose molecules, by presenting a reduced cohesion, adapt to the shape of the container that houses them. The term comes from the Latin word liquĭdus .
Liquid is understood as one of the states of aggregation of matter . Its molecules have less cohesion than a solid, but greater than a gas. While its volume is defined, its shape is not fixed.
Surface tension and capillarity are two characteristics of liquids. Typically, when the temperature increases, the liquid expands, whereas when it cools, its volume tends to decrease.
The most abundant liquid on planet Earth is water . This substance, whose molecules are made up of two hydrogen atoms and one oxygen atom, is usually found in liquid state in oceans, rivers, lakes, etc.
Drinks that a person ingests, on the other hand, can be considered liquids. Mineral water, soda, juice, wine and beer, to name a few, are liquids that are drunk from glasses or cups.
Many remedies , on the other hand, are marketed as liquids of varying viscosity. A cough syrup, in this context, is a liquid.
Two thirds of our body 's contents are made up of liquid. For this reason, it is essential to drink a good amount of water every day to regulate bone mass, muscle mass and blood. Hydrating our body should be a natural task: our most remote ancestors probably drank whenever they needed it, as long as they had a water source nearby. In our case, however, modern life does not always give us this possibility.
For this reason, we need to be prepared for situations such as “a long train journey” or “a long walk” and always have a bottle of fresh water with us. Even when we are in the comfort of our home, at the first sign of dryness in the throat we should drink liquids as a basic rule for good health .
In the field of physics and chemistry, the term change of state refers to the evolution that matter undergoes when it passes from one state of aggregation to another without its composition being affected. The "state of aggregation" is a phase that is characterized by the values that certain properties of the matter have, given certain conditions, such as pressure or temperature.
The three best-known states are liquid, solid and gas, although there are others, such as plasma , the most common in the Universe since it can be seen in the composition of stars.
The transition from a solid to a liquid state, for example, is called fusion and occurs through heat . Precisely, throughout this process, characterized by the absorption of energy, there comes a point at which the temperature becomes constant, and this is known as the " melting point ". It is then that the molecules of matter begin to move independently, giving rise to the liquid state. The value of the temperature at which the melting point occurs is different for each substance.
The opposite process is called solidification , and occurs through cooling. In this case, the liquid must reach the "solidification point" or " freezing point ", the temperature at which it turns into a solid state; this value also varies depending on the material in question.
In the field of economics and accounting, finally, liquidity is the quality of an asset that can be immediately converted into cash without losing value. This means that a liquid asset is one that can be easily transformed into money or that is already in the form of money.