The term "amorphous" is translated from Greek literally as "not a form", "not a form." Such substances do not have a crystalline structure; they do not undergo splitting with the formation of crystalline faces. As a rule, an amorphous body is isotropic, that is, its physical properties are independent of the direction of external action.
Amorphous substances include glass (volcanic and artificial), adhesives, resins, etc. Glass is considered to be a solid state of an amorphous body. Thus, substances can remain in a glassy state under the influence of low temperatures. Under the influence of elevated temperatures, they turn into a state of melt. The viscosity of amorphous substances depends on temperature: the higher it is, the lower this indicator will be.
The properties of amorphous bodies make it possible to put them in an intermediate place between liquids and crystals. In this regard, they can hardly be called solid.
The melting of amorphous bodies is one of the main characteristics of these substances. You can conduct an experiment. He will need a stearin candle, plasticine and an artificial heat source (heater). Both the candle and the clay are placed at an equal distance from the heater. After some time, part of the candle will begin to melt. In this case, clay will only become softer. After a while, the candle will melt completely. Plasticine will become quite soft.
There are other substances like stearin, such as metals. When heated, they do not soften, but melt. In this process, one can always observe both the still solid and the already liquid part of the substance. These bodies are crystalline.
There are also substances which, when heated, soften gradually and become more fluid. In these cases, it is impossible to indicate the temperature at which they soften. These are amorphous bodies. They have fluidity even under the influence of low temperatures. This can be confirmed by experience.
In a glass funnel, put a piece of resin and leave it at room temperature. After a few weeks, it will be seen that the resin not only took the form of a funnel, but also began to flow out of it like a stream. This experiment confirms that amorphous bodies behave as very viscous and thick liquids.
When studying them using x-rays and an electron microscope, it was found that in these substances the particles are not arranged in a strict order. For crystals, for example, the so-called long-range order, according to which the arrangement of particles is carried out, is characteristic. Amorphous bodies differ in the short-range order of arrangement. This means that a certain degree of ordering in the arrangement is preserved only near each individual particle.
It was established that in these substances (as, in fact, in others), the particles oscillate randomly and continuously. However, in amorphous bodies, they can jump from one place to another. This is facilitated by the unequally dense arrangement of particles in amorphous substances — relatively large gaps also take place. But these distances are not "vacant", as, for example, in crystalline substances.
Over a certain period of time (months, weeks, days), individual amorphous bodies can spontaneously transform into a crystalline state. So, for example, you can observe how honey or sugar candy lose transparency after some time. In such cases, it is usually said that the products are “sugared”. At the same time, scooping up the candied honey with a spoon or breaking a lollipop, you can really observe the formed sugar crystals that previously existed in an amorphous form.
Such spontaneous crystallization of substances indicates a different degree of stability of states. Thus, an amorphous body is less stable.