The large regular crystal grows.
name: Seed crystal grows in saturated solution.
Учимся выращивать красивые кристаллы из солей! (химия)
Growing and Crystallization of copper (II) sulphate crystals
by Mr Guay Hansen
Wear eye protection goggles and gloves.
Always follow general safety
recommendations. Please note that conducting chemistry
experiments you must comply with the relevant legal procedures in
- First we need to prepare the seed crystal. Fill one third of the beaker with salt (cooper sulfate or sodium chloride).
- Pour hot water into the beaker. The volume of water added is close to the beaker volume.
- Stir the solution to dissolve all the salt.
- To make the solution saturated add salt until it stops dissolving.
- Filter the solution. Put a funnel with filter paper in an empty beaker. Pour the solution through the funnel.
- Add a few salt crystals to the solution.
- Leave the solution for a while.
- Crystals are formed on the bottom of the beaker.
- Take one of these crystals. The crystal should have regular shape and their size must be close to pea size.
- Tie crystal with thread.
- Bind the free end of the thread to the beaker lid or to a rod.
- Put the seed crystal into the saturated salt solution.
- Growing a large crystal may take a few weeks.
- In order to keep the regular shape of the crystal, change the solution once or twice a week. Take out the crystal and filter the solution. Then place the crystal back.
- When the crystal becomes large enough pull it out of the solution.
- Dry it with a wiper.
- To preserve the crystal cover it with two layers of polish.
In this experiment salt crystals are formed from the saturated solution. A solution is called saturated if the substance can dissolve no more and its subsequent addition will lead to precipitate formation. Solubility of substances increases with temperature. When the solution is cooled down salt could no longer stay in the solution and begins to form crystals. Crystallization process could be divided into two main steps: nucleation and growth. Nucleation is the process of initial formation of nanometer size clusters of solute molecules and their arrangement together. This process is the beginning of phase change. It continues in the second step – the growth process. When solute molecules touch the earlier formed nucleus they increase the crystal dimensions.