term "amorphous" is literally translated from Greek as "not kind", "no form".Such substances do not have a crystalline structure, they do not undergo cleavage with formation of crystal faces.Typically, the amorphous body is isotropic, that is, its physical properties do not depend on the direction of the external impact.
Amorphous substances include glass (volcanic and artificial), adhesives, resins, and so on. D. Solid state body is considered to be amorphous glass.Thus, the substance may remain in the vitreous state under the influence of low temperatures.Under the influence of higher temperatures they move into a state of melt.The viscosity of amorphous materials depends on the temperature: the higher it is, the lower the rate.
properties of amorphous solids allow you to put them in an intermediate position between the liquid and crystals.In this regard, they are difficult to unambiguously called solid.
melting amorphous solids - one of the main characteristics of these substances.You can spend experience.For him the need stearic candle, clay and artificial heat source (heater).And candles, clay and placed at an equal distance from the heater.After some time, will begin to occur melting of the candle.This will be a softer clay.Some time later, the candle melts completely.Clay will become very soft.
There are other similar stearin substances - such as metals.When heated they do not soften and melt.In this process it is always possible to see how even a solid, and has a liquid portion of the substance.These bodies are crystalline.
There are substances that are heated, softened gradually and become more fluid.In these cases, indicate the temperature at which they soften, it is impossible.This - the amorphous body.They possess fluidity even under low temperatures.This can be confirmed by experience.
The glass funnel should put a piece of gum and leave it at room temperature.A few weeks later it will be seen that the resin not only took the form of a funnel, and began to flow out of her like a jet.This experience proved that amorphous bodies behave as a very viscous and thick liquid.
When studying them using X-ray and electron microscope revealed that the particles of these substances are not located in a strict order.Crystals is typical, for example, the so-called long-range order, by which the alignment of the particles.Amorphous body different short-range order arrangement.This means that some degree of order in the arrangement is saved only in the vicinity of each individual particle.
established that these substances (as, indeed, in the other), the particles oscillate randomly and continuously.However, amorphous solids, they can jump from one place to another.This contributes differently dense arrangement of particles in amorphous materials - there are relatively large gaps.However, these distances are not "vacant", such as a crystalline solid.
During a certain period of time (months, weeks, days) the individual amorphous body can spontaneously go into the crystalline state.Thus, for example, can be observed as honey or sugar candy after a time to lose transparency.In such cases, usually say that the products are "sugar."At the same time, scooping spoon honey candied candy or breaks, you can actually watch the sugar crystals formed that previously existed in the amorphous form.
This spontaneous crystallization of substances indicates different degree of stability of the state.Thus, less stable amorphous body.