Interesting chemical experiments: http://www.m.chemicum.com/
Hello everyone. Today we will grow some crystals, again. As in the previous video, I will try to describe the whole process of growing the crystals to you.
First, we need to choose the material of which we will grow the crystal. Essentially, practically any substance is suitable for crystal growth.
For example: protein crystals, crystals of iodine, metals crystals. Even air can be turned into a crystal when it is cooled to a certain temperature.
For normal conditions, the best suited are inorganic salts. And for this time I will grow crystals of potassium alum.
However, from personal experience, I would say that copper sulfate is the best substance for growing crystals at home. Table salt is not the best material. Bluestone is easier to buy and you will get beautiful blue crystals using it.
To begin, let’s take any vessel and pour there some of our salt. Next, pour hot water into the vessel and keep adding salt until it is no longer dissolvable.
In this case, we get a saturated solution. Be sure to add hot water, to be safe with the proportions.
Different salts have their own solubility curves.
Solubility curve is a measure of how many grams of the salt can be dissolved in a 100 ml of water at a certain temperature.
Also, for all of the salts the information is different. Once we have prepared our saturated salt solution, it has to be filtered while it is still hot.
Filtering is not required. However, if you buy the chemicals in a garden shop, not in a special shop, the solution must be thoroughly cleaned from possible impurities.
I would still recommend to initially use pure chemicals.
After the filtration, let’s leave our glass for a few days to let the crystals form.
Crystals form as a result of the change in solubility of salts in the water when the temprature changes. Excess crystals, which cannot be dissolved in the solution, they fall to the bottom of the cup.
After a day we may notice that beautiful crystals were formed at the bottom of the beaker. These crystals will be used as seeds.
Seed is a small crystal that is immersed into the solution, which will continue to grow new layers of a crystal on top of it. Now let’s merge the solution into another beaker.
Next, choose the most beautiful and large crystal from the mass of crystals that were formed on the bottom of the cup, or the one that is easiest to tie on a thread. I could also advise here to use a thin fishing line instead of threads.
Once we have tied a crystal to a beaker we pour our saturated solution of salt back there. You can tie a thread to a regular pencil and hung a crystal in a glass using it.
However, for myself I’ve decided to use a system, in which the glass will be protected from dust. I think this is not necessary. At the moment we can only wait for the crystal to grow.
Over the time of the growth of the crystal, it will become bigger and bigger. This occurs because the water from the solution will gradually evaporate, thereby increasing the concentration of the solution.
Since we have a solubility curve, we can learn that the excess material that cannot be dissolved must go somewhere. And this is the substance that forms our single crystal.
If we had not hung the seed, the crystals would have started to fall anywhere – on the bottom or on the walls of the beaker. And one more thing to mention!
During the process of crystals growing, liquid from the cup will gradually evaporate, and therefore the crystals grow. But, that’s also a problem.
During the evaporation of liquid it comes to a certain time when there won’t be enough solution in the cup anymore, and the further growth of the crystal will be impossible.
To solve this, once a month or once in every two weeks it is necessary to add a saturated solution into the beaker. The saturated solution must be prepared the same way as it was before, by adding salt into a hot water.
However, you should not add a warm solution. The saturated solution should be the same temperature as the growing crystal.
Also, once a month or once every two weeks, I recommend filtering solution to maintain its cleanliness.
Over time, in the solution some specks or other dirt might occur, which can screw up the crystal.
Over time, my crystals from potassium alum become bigger.
As you can see, they have acquired a very interesting form. And now, after about 3 months, I have grown two beautiful crystal of potassium alum. Facebook: https://www.facebook.com/thoisoi2