We explain what the solid state is and what are the physical characteristics of this state of matter. Examples of solids.
What is the solid state?
It is called solid state to one of the four essential ways in which matter is presented , together with liquid , gaseous and plasma . These forms are called states of aggregation of matter.
Solid state matter (or simply solids) is characterized by a specific arrangement of its particles , based on very rigid and strong links, which translates into a very well defined physical structure . These cohesion forces between the particles keep the solid shape and volume stable, and give it a certain margin of hardness and strength.
However, these forces can be overcome through physical processes of phase change, being able to convert a solid into a liquid or a gas, and which are:
- Merger . It consists in increasing the temperature of a solid until it reaches the maximum it can absorb (called the melting point ), from which the excess energy overcomes the nexus between the particles, making them move faster and break their stationary state, then flowing as liquid.
- Sublimation . Certain solids can be converted to gases directly, without first going through a liquid state, if heat is added andsufficient pressure conditions are handled. It is what happens, for example, with the ice in the very cold and dry places so that the water arises.
Physical characteristics of the solid state
The solid state matter has the following fundamental characteristics:
- Cohesion . Although solids have a chemical nature identical to their liquid and gaseous versions, their particles are close together, held in place by very strong bonds, called cohesive forces. That is the reason that the set has a definite form, of clear limits and its own volume.
- Rigidity . Solid matter usually resists deformation: kinks, bends, crevices, even in the presence of constant forces such as weight or gravity . Only if such resistance is overcome, solids change shape (permanently or temporarily, depending on their elasticity ).
- Incompressibility . Unlike gases and liquids, solids can no longer be compressed, that is, their particles can no longer be together. On the other hand, when subjected to extreme compression forces, they tend to fracture or decompose into smaller pieces.
- Toughness . In general, solids are resistant to being penetrated by other solids, even when their surface is scratched. This is known as hardness, physical strength against the action of other solids. The hardest matter known is diamond.
- Elasticity . Contrary to fragility and hardness, elasticity is that certain solids can undergo a momentary deformation, under the action of a force, and then return to their original form once said force is finished. Elastic materials have a memory in a way that allows them to return to their previous arrangement.
Solid State Examples
Some examples of solid state matter are:
- Metals . With the sole exception of mercury (Hg), metals at room temperature retain their strength and hardness, which is the product of the metallic bonds between their atoms . However, given enough heat, as in the forges or foundries, metals flow like liquids and can acquire other forms.
- Ice . Liquid water, when taken to its freezing point, that is, when caloric energy is removed until it is brought to 0 ° C, it proceeds to crystallize and become ice, a transparent and solid substance.
- Stones . Composed of minerals and calcareous or sedimentary elements, the stones we find on any path are the clearest example of solidity possible on the planet. Many would be impossible to make them flow like liquid.
- Concrete . The result of the union of materials such as gravel, water and cement powder, first as a wet paste and then as an extremely hard material when dried, is used daily in the construction industry.
- Bones . Mineralized with calcium taken from our diet, the bones of our body or the body of any vertebrate animal are those that provide the greatest solidity to the body, protecting it from the action of the outside world through its hardness and stiffness.