Crystals are solid substances whose building blocks line up in a repeating pattern to form a crystal lattice. In a science kit, you grow crystals by making a solution that contains the crystal material and then letting it change so crystals can form.
How it works in a kit:
- Dissolve the powder: Heat water and stir in the powdered crystal material until no more will dissolve. You make a hot, concentrated liquid.
- Make the solution saturated or supersaturated: If you add a bit more powder than the liquid can hold at that temperature, the solution becomes supersaturated and wants to form crystals.
- Cool or evaporate: When the liquid cools or water evaporates slowly, the dissolved molecules start sticking together in a regular pattern. They often attach to a seed crystal or to the starting string/pipe cleaner.
- Grow crystals: More molecules join the growing crystals, making them bigger over time. The shape depends on the material and how it grows.
- Finish: After several hours to a day, you can observe sparkling crystals with a repeating structure.
Tips for better crystals:
- Use a clean jar and a clean starting object (seed) like a pipe cleaner or a string.
- Ask an adult to help with hot water and handling hot things.
- Do not taste or swallow the powder or solution.
- Different substances and temperatures create different colors and shapes.
Why crystals form in a kit
- The kit provides a soluble powder and a container. When the solution becomes saturated or supersaturated and then cools or evaporates, the dissolved atoms or molecules arrange themselves into a crystal lattice on a seed or sparkly surface.