Growing ruby crystals and other artificial stones at home. Applications of artificial crystals Artificial crystals and their applications

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Research

CRYSTALS AND THEIR APPLICATIONS

Author of the work: Krivosheev Evgeny

student 7"B" class MBOUSOSH No. 1

City of Zavitinsk, Amur Region

Work manager: Konchenko N.S.

physics teacher MBOUSOSH №1

City of Zavitinsk, Amur Region

Zavitinsk.

2013

Introduction
1. Crystal. Its properties, structure and form
2. Liquid crystals
3. LCD application
4. Application of crystals in science and technology
5. Practical part
Conclusion
Bibliography
Introduction
The relevance of the work:
Since crystals are widely used in science and technology, it is difficult to name a branch of production where crystals would not be used. Therefore, it is very important for every person to know and understand the properties of crystals.
Purpose of the study: Growing a crystal from a solution at home, studying the practical application of crystals in science and technology.
Tasks:
1. The study of the theory of crystals.
2. Study of the material for growing a crystal under normal conditions and in laboratory conditions.
3. Observation of the formation of a crystal.
4. Description of observations.
5. Study of the scope of crystals in modern life.

1. Crystal. Its properties, structure and form

The word "crystal" comes from the Greek " crustallos”, that is, “ice”. Solids whose atoms or molecules form an ordered periodic structure (crystal lattice).

Crystal formation.

Crystals form in three ways: from a melt, from a solution, and from a vapor. An example of crystallization from a melt is the formation of ice from water. crystal liquid growing laboratory

In the world around us, one can often observe the formation of crystals directly from a gaseous medium, from solutions, and from a melt. On a quiet frosty night with a clear sky, in the bright light of the moon or a lantern, we sometimes see flakes of frost slowly descending, sparkling with sparks. These are lamellar ice crystals, which are formed right next to us from moist and cooled air.

The structure of solids depends on the conditions under which the transition from liquid to solid occurs. If such a transition occurs very quickly, for example, during a sharp cooling of the liquid, then the particles do not have time to line up in the correct structure and a finely crystalline body is formed. When the liquid is slowly cooled, large and regular crystals are obtained. In some cases, in order for the substance to crystallize, it has to be kept at different temperatures. External pressure also affects crystal growth. In addition, a significant part of the crystals, which in the distant past had a perfect cut, managed to lose it under the influence of water, wind, friction against other solids. Thus, many rounded transparent grains that can be found in coastal sand are quartz crystals that have lost their faces as a result of prolonged friction against each other.

The structure of crystals

The variety of crystals in form is very large.

Crystals can have from four to several hundred facets. But at the same time, they have a remarkable property - whatever the size, shape and number of faces of the same crystal, all flat faces intersect with each other at certain angles. The angles between the corresponding faces are always the same. The shape is influenced by factors such as temperature, pressure, frequency, concentration and direction of movement of the solution. Therefore, crystals of the same substance can exhibit a wide variety of forms.

Rock salt crystals, for example, may have the shape of a cube, a parallelepiped, a prism, or a body of a more complex shape, but their faces always intersect at right angles. The faces of quartz have the shape of irregular hexagons, but the angles between the faces are always the same - 120°.

The law of constancy of angles, discovered in 1669 by the Dane Nikolai Steno, is the most important law of the science of crystals - crystallography.

The measurement of the angles between the faces of crystals is of great practical importance, since the nature of the mineral can be reliably determined from the results of these measurements in many cases.

The simplest instrument for measuring the angles of crystals is an applied goniometer.

Types of crystals

In addition, single crystals and polycrystals are distinguished.

A monocrystal is a monolith with a single undisturbed crystal lattice. Large natural single crystals are very rare.

Single crystals are quartz, diamond, ruby and many other precious stones.

Most crystalline bodies are polycrystalline, that is, they consist of many small crystals, sometimes visible only under high magnification.

All metals are polycrystals.

2. liquid crystals

liquid crystal - This is a special state of matter, intermediate between the liquid and solid states. Molecules in a liquid are free to rotate and move in any direction. In a liquid crystal, there is some degree of geometric order in the arrangement of molecules, but some freedom of movement is also allowed.

The consistency of liquid crystals can be different - from easily flowing liquid to pasty. Liquid crystals have unusual optical properties that are used in technology. Liquid crystals are formed from molecules that have different geometric shapes. such as color, transparency, etc. Numerous applications of liquid crystals are based on all this.

3. LCD application

The arrangement of molecules in liquid crystals changes under the influence of factors such as temperature, pressure, electric and magnetic fields; changes in the arrangement of molecules lead to a change in optical properties, such as color, transparency, and the ability to rotate the plane of polarization of transmitted light. Numerous applications of liquid crystals are based on all this. For example, the dependence of color on temperature is used for medical diagnosis. By applying certain liquid crystal materials to a patient's body, the physician can easily identify diseased tissues by discoloration where these tissues generate increased amounts of heat. The temperature dependence of color also makes it possible to control the quality of products without destroying them. If a metal product is heated, then its internal defect will change the temperature distribution on the surface. These defects are detected by a change in the color of the liquid crystal material deposited on the surface.

Thin films of liquid crystals enclosed between glasses or plastic sheets have found wide application as indicator devices. Liquid crystals are widely used in the manufacture of watches and small calculators. Flat-panel televisions with a thin liquid crystal screen are being created.

4. Application of crystals in science and technology

Nowadays, crystals are widely used in science, technology and medicine.

Diamond saws cut stones. A diamond saw is a large (up to 2 meters in diameter) rotating steel disk, on the edges of which notches or notches are made. Fine diamond powder, mixed with some kind of sticky substance, is rubbed into these cuts. Such a disk, rotating at high speed, quickly cuts any stone.

Diamond is of great importance when drilling rocks, in mining. Engraving tools, dividing machines, hardness testers, stone and metal drills have diamond points inserted. Diamond powder is used for grinding and polishing hard stones, hardened steel, hard and superhard alloys. The diamond itself can be cut, ground and engraved only by the diamond itself. The most critical engine parts in the automotive and aviation industry are processed with diamond cutters and drills.

Corundum can be used for drilling, grinding, polishing, sharpening stone and metal. Grinding wheels and whetstones, grinding powders and pastes are made from corundum and emery. In semiconductor factories, the finest circuits are drawn with ruby needles.

Garnet is also used in the abrasive industry. Grinding powders, grinding wheels, skins are made from garnets. They sometimes replace ruby in instrument making.

Lenses, prisms, and other parts of optical instruments are made from transparent quartz. The artificial "mountain sun" is an apparatus widely used in medicine. When turned on, this device emits ultraviolet light, these rays are healing. In this device, the lamp is made of quartz glass. A quartz lamp is used not only in medicine, but also in organic chemistry, mineralogy, it helps to distinguish fake stamps, banknotes from real ones. Pure, defect-free rock crystals are used in the manufacture of prisms, spectrographs, and polarizing plates.

Fluorite is used to make lenses for telescopes and microscopes, to make spectrograph prisms, and in other optical instruments.

5. Practical part

Growing crystals of copper sulfate.

Copper sulphate is copper sulfate pentahydrate, as large crystals resemble colored blue glass. Copper sulfate is used in agriculture to control pests and plant diseases, in industry in the production of artificial fibers, organic dyes, mineral paints, arsenic chemicals.

How to grow at home:

1) First, let's prepare a solution of concentrated vitriol. After that, slightly heat the mixture to achieve complete dissolution of the salt. To do this, put the glass in a saucepan with warm water.

2) Pour the resulting concentrated solution into a jar or beaker; we will also hang a crystalline "seed" on a thread - a small crystal of the same salt - so that it is immersed in the solution. On this "seed" the future exhibit of your collection of crystals will grow.

3) Place the vessel with the solution open in a warm place. When the crystal grows large enough, take it out of the solution, dry it with a soft cloth or paper towel, cut off the thread and cover the edges of the crystal with a colorless varnish to protect it from "weathering" in the air.

Observation of the process of growth of copper sulfate crystals.

To begin with, we poured a solution of copper sulfate into a chemical beaker, tied a seed to a thread. And they lowered the crystal into the glass. The very next day we had a rather large polycrystal, about 2 centimeters in length. The crystal itself was very uneven, with small columns. Further crystallization did not continue, no matter how long we waited.

But we did not stop there and made two more crystals of copper sulfate. We only took the seed from the column of the failed crystal. In one solution, the temperature was constantly changing, and in the other glass it was unchanged. After a few days, we got two full-fledged single crystals of copper sulphate. They turned out with smooth edges, absolutely symmetrical. So I realized that in order to make an even crystal, the seed must also be even and symmetrical.

Observation of the process of crystal growth in salt solutions under a microscope.

It is very interesting to examine crystals under a microscope, since the "younger" the crystal, the more regular shape it has. The study of crystals under a microscope does not take much time and resources: only a few grams of salt are needed to prepare a solution, and it does not take much time for a crystal to grow.

A few drops of a saturated solution of various salts were applied to a microscope slide. The glass was slightly heated by the flame of an alcohol lamp and placed on the microscope stage. By moving the slide and adjusting the magnification, we achieved such a position that the drop occupied the entire field of view of the microscope. After a short time interval (about 1 min), crystallization began at the edge of the drop, where it dries faster. The small crystals formed formed a continuous opaque crust along the edges of the drop, which appeared dark in transmitted light. Gradually, from this mass of crystals, individual points of individual crystals began to emerge, pointing inwards into drops, which, growing, form various forms. Most often, new crystallization centers in the free space inside the drop, as a rule, did not spontaneously arise. After some time, the entire field of view was filled with crystals, and the crystallization was almost completed.

Conclusion

Thus, crystals are one of the most beautiful and mysterious creations of nature. We live in a world consisting of crystals, we build from them, we process them, we eat them, we are treated by them ... The science of crystallography is engaged in the study of the variety of crystals. She comprehensively considers crystalline substances, explores their properties and structure. In ancient times, it was believed that crystals are rare. Indeed, the presence in nature of large homogeneous crystals is an infrequent phenomenon. However, fine-grained substances are quite common. So, for example, almost all rocks: granite, sandstone, limestone - are crystalline. Even some parts of the body are crystalline, for example, the cornea of the eye, vitamins, the sheath of nerves. The long path of searches and discoveries, from measuring the external form of crystals in depth, to the subtleties of their atomic structure, has not yet been completed. But now researchers have studied its structure quite well and are learning to control the properties of crystals.

As a result of the work carried out, I can draw the following conclusions:

1. A crystal is a solid state of matter. It has a certain shape and a certain number of faces.

2. Crystals come in different colors, but are mostly transparent.

3. Crystals are not a museum rarity at all. Crystals are all around us. Solids from which we build houses and make machines, substances that we use in everyday life - almost all of them belong to crystals. Sand and granite, table salt and sugar, diamond and emerald, copper and iron are all crystalline bodies.

4. The most valuable among crystals are precious stones.

5. I grew a crystal at home from a saturated solution of copper sulfate.

Thus, the goals and objectives that were outlined by me at the beginning of the work have been achieved. As a result of the work done, I empirically found evidence for the assumption that was made by the English crystallographer Frank about the stepwise growth of crystals.

The work done was very interesting and entertaining. I would also like to grow crystals from other substances, because there are so many of them around us ...

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organic salts

It is easy to grow a ruby crystal from various salts:

copper sulphate;
potassium alum;
regular salt.

The longest salt-based process, the most beautiful samples are obtained from vitriol. The production of ruby crystals is based on the following steps:

Tank preparation. It should hold salt and a saturated water-salt solution. Take hot water. The process is gradual. Dilute two tablespoons with water, mix thoroughly. Then salt is added and mixed. it is necessary to shower until the salt ceases to dissolve. To keep the proportions, they take a hint: a table of the solubility of different salts in 100 ml of water, their relationship with the temperature of the liquid.
Solution filtration. The solution must be clean. Dirt impurities will spoil the structure of the stone. It will show defects. The solution remains for 24 hours. During this period, crystals form at the bottom of the container. They will become the basis of the ruby.
The growth of an artificial mineral. A fishing line is tied to the stone formed at the bottom of the glass. It is wound on a pencil or wooden stick. The device is installed on the tank. The crystal is in solution, suspended. Water tends to evaporate, a saturated saline solution releases excess, which is fixed on the resulting sample.
Adding a salt solution. Water always needs a certain amount, if it becomes scarce, the crystal will stop growing. At normal room temperature, water is added once every 2 weeks.

artificial crystals

For a long time, man has dreamed of synthesizing stones that are as precious as those found in natural conditions. Until the 20th century, such attempts were unsuccessful. But in 1902 it was possible to obtain rubies and sapphires, which have the properties of natural stones. Now such minerals are produced by millions of carats annually!

Later, in the late 1940s, emeralds were synthesized, and in 1955 the General Electric Company and the Physical Institute of the USSR Academy of Sciences reported on the manufacture of artificial diamonds.

The many technological needs for crystals have spurred research into methods for growing crystals with predetermined chemical, physical, and electrical properties. The work of researchers was not in vain, and ways were found to grow large crystals of hundreds of substances, many of which have no natural analogue. In the laboratory, crystals are grown under carefully controlled conditions to ensure the desired properties, and laboratory crystals are formed, just as in nature - from solution, melt or vapor.

The use of artificial crystals

The applications of crystals in science and technology are so numerous and varied that it is difficult to enumerate them. Therefore, we confine ourselves to a few examples.

The hardest and rarest of natural minerals is diamond. Today, a diamond is primarily a stone-worker, not a stone-decoration. Due to its exceptional hardness, diamond plays a huge role in technology. Diamond saws cut stones. A diamond saw is a large (up to 2 meters in diameter) rotating steel disk, on the edges of which notches or notches are made. Fine diamond powder, mixed with some sticky substance, is rubbed into these incisions. Such a disk, rotating at high speed, quickly cuts any stone. Diamond is of tremendous importance in rock drilling and in mining operations. Diamond powder is used to grind and polish hard stones and hardened steel. The diamond itself can be cut, polished and engraved only with a diamond. The most critical engine parts in the automotive and aviation industry are processed with diamond cutters and drills.

Ruby and sapphire are among the most beautiful and most expensive gemstones. All these stones have other qualities, more modest, but useful.

They also have a completely nondescript brother: brown, opaque, fine corundum - emery, which is used to clean metal, from which emery skin is made. Corundum with all its varieties is one of the hardest stones on Earth, the hardest after diamond. Corundum can be used for drilling, grinding, polishing, sharpening stone and metal. Grinding wheels and whetstones, grinding powders are made from corundum and emery.

The entire watch industry works on artificial rubies. The ruby's new life is the laser, the marvelous instrument of our day. In 1960 The first ruby laser was created. It turned out that the ruby crystal amplifies the light. The laser shines brighter than a thousand suns. Powerful beam - huge power. It easily burns sheet metal, welds metal wires, burns metal pipes, drills the finest holes in hard alloys, diamond. These functions are performed by a solid laser, where ruby and garnet are used. In eye surgery, ruby lasers are most often used.

Sapphire is transparent, so plates for optical instruments are made from it.

Flint, amethyst, jasper, opal, chalcedony are all varieties of quartz. Small grains of quartz form sand. And the most beautiful, most wonderful variety of quartz is rock crystal, i.e. transparent quartz crystals. Therefore, lenses, prisms, and other parts of optical instruments are made of transparent quartz. The electrical properties of quartz are especially surprising. If you compress or stretch a quartz crystal, electric charges appear on its faces.

Also, crystals are widely used for reproducing, recording and transmitting sound. There are also crystalline methods for measuring blood pressure in human blood vessels and pressure of juices in stems and trunks of plants. The electro-optical industry is the industry of crystals. It is very large and diverse, hundreds of types of crystals are grown and processed at its factories for use in optics, acoustics, radio electronics, and laser technology.

In technology, the polycrystalline material Polaroid has also found its use. Polaroid films are used in polaroid glasses. Polaroids block out the glare of reflected light while allowing all other light to pass through. They are indispensable for polar explorers, who constantly have to look at the dazzling reflection of the sun's rays from the icy snow field.

Polaroid glasses will help prevent oncoming car collisions, which very often happen due to the fact that the lights of an oncoming car blind the driver, and he does not see this car. If the windshields of cars and the glass of car lamps are made of polaroid, then the windshield will not let the light of the oncoming car's lamps through, "extinguish it."