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Modern industry cannot do without a wide variety of crystals. They are used in watches, transistor receivers, computers, lasers and many others. The great laboratorium - nature - can no longer satisfy the demand of developing technology, and so artificial crystals are grown in special factories: small, almost imperceptible, and large ones - weighing several kilograms.
There are different ways to grow crystals. Often this process requires high temperatures and enormous pressure (for example, to obtain artificial diamonds), but some crystals can be grown even at home. We will tell you how this can be done.
The easiest way to grow crystals of aluminum alum at home is KAl(SO₄)₂·12H₂O. This substance can be bought at any chemical store, and it is absolutely harmless (alum is sometimes even added to drinking water to clear it of turbidity). But before we get started, let’s take a look at what the crystal growing process is all about.
If you dissolve a substance in water at a constant temperature, then after some time, what appears to be the dissolution process stops. Such a solution is called saturated, and the maximum amount of a substance that can be dissolved at a given temperature in 100 °C water is called its solubility. Obviously, with increasing temperature, solubility increases. Therefore, a saturated industry cannot do without a wide variety of crystals. They are used in watches, transistor receivers, computers, lasers and many others. The great laboratorium - nature - can no longer satisfy the demand of developing technology, and so artificial crystals are grown in special factories: small, almost imperceptible, and large ones - weighing several kilograms.
There are different ways to grow crystals. Often this process requires high temperatures and enormous pressure (for example, to obtain artificial diamonds), but some crystals can be grown even at home. We will tell you how this can be done.
The easiest way to grow crystals of aluminum alum at home is KAl(SO₄)₂·12H₂O. This substance can be bought at any chemical store, and it is absolutely harmless (alum is sometimes even added to drinking water to clear it of turbidity). But before we get started, let’s look at what the dissolution process is like when it stops. Such a solution is called saturated, and the maximum amount of a substance that can be dissolved at a given temperature in 100 °C water is called its solubility. Obviously, with increasing temperature, solubility increases. Therefore, a saturated industry cannot do without a wide variety of crystals. They are found in watches, transistor receivers, computers, lasers and many others. The great laboratorium - nature - can no longer satisfy the evolving technology, and so artificial crystals are grown in special factories: small, almost imperceptible, and large ones - weighing several kilograms.
There are different ways to grow crystals. Often this process requires high temperatures and large amounts of water, which can cause damage to the crystal structure. Therefore, it is recommended to use a specialized laboratory for growing crystals.
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saturated at one temperature, becomes undersaturated at a higher temperature. If the saturated solution is cooled, the excess substance precipitates. figure 1 shows the dependence of the solubility of aluminum alum on temperature. The graph shows that, for example, when cooling to 10°C 100 g of a solution that was saturated at 30°C, more than 10 g of the substance should precipitate. Therefore, one way to grow crystals is to allow the saturated solution to cool.
Crystals can also be grown by evaporation. After all, if a saturated solution evaporates, its volume decreases, but the amount of dissolved substance remains the same. In other words, an excess of substance is again created, which precipitates.
Let us now consider how the release of excess substance occurs.
Take a saturated solution and heat it. Cover the vessel with the resulting undersaturated solution with glass and allow the solution to cool quietly to a temperature lower than the saturation temperature. In this case, the precipitate may not fall out, and we will get a supersaturated solution. The fact is that for education
To form a crystal, a “seed” is necessary. It can be a small crystal of the same substance or a simple speck of dust. Sometimes it is enough to quickly remove a vessel with a supersaturated solution or remove the glass covering it, as instant crystallization begins. In this case, many small crystals are usually formed. In order to grow a large crystal, it is necessary to limit the number of “seeds”. It is best to introduce an artificial “seed”, the role of which will be played by one of the crystals obtained earlier.
The “seed” is prepared as follows. Take two glass jars and wash them thoroughly. Pour warm water into one of them and saturate it with alum. When placing the solution, watch for dissolution. When the substance stops dissolving, carefully pour the solution into the second jar so that no undissolved substance gets into it. Then cover the jar with glass. When the solution has cooled, chemistry the glass. After a while, you will see many crystals forming in the jar. Let them grow and select the largest ones for “seeding”.
Now you can start growing the crystal. First of all, you need to prepare the dishes. To destroy unwanted items -
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Shea on the walls, steam the inside of the jars over the spout of a boiling kettle. Then make a warm, saturated solution again and pour it into another clean jar.
So, you have a warm saturated alum solution. Heat it a little more, cover the jar with glass and leave to cool. When the temperature of the solution approaches the saturation temperature, put the previously prepared “dressing” into the jar. Since the solution is still undersaturated, the “priming” crystal begins to dissolve. But as soon as the solution cools to the saturation temperature, the dissolution of the crystal will stop, and soon its growth will begin. (If the crystal dissolves entirely, you can add a new “filling” to the solution.))
When the solution stops cooling, crystal growth can be continued. To do this, lift the glass so that the water evaporates, but dust particles do not fall into the solution. Crystal growth continues for two to three days.
When growing a crystal, be careful not to touch or move the jar. When the crystal is ready, just remove it from the solution and blot it thoroughly with a paper towel, otherwise it will quickly fade.
The crystals come out differently in shape depending on whether you drop the dressing at the bottom of the sauce or hang it on a string (Fig. 2). In this way you can, for example, grow “beads”. To do this, you need to “thread” the thread, that is, pass it several times along the crystal, and then lower the thread into the solution.
The photo of the graphic placed at the beginning of the stats shows a crystal obtained from potassium alum using the above method.
Growing crystals is an art. You may not succeed in everything right away. Don’t be upset. A little persistence, perseverance, accuracy, and you will become the owner of beautiful crystals.
To questions from readers
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