- 1 medium jar
- 2 cups (480ml) water
- Small saucepan
- Heatproof measuring cup
- 3/4 cup (225g) Epsom salt
- Mixing spoon
- Food colouring
Crystals are groups of atoms that are formed in an organized way. Different kinds of crystals have different shapes. They are formed in nature when liquids cool and begin to harden. The molecules gather together in a specific pattern that repeats to result in a crystal.
Some crystals form when magma, a liquid form of rock, cools; when the magma cools slowly, a crystal has time to grow. Some crystals turn into diamonds, rubies, or emeralds. Other kinds of crystal are formed when water evaporates from a saltwater mixture. Salt crystals also form
as water evaporates. This is the kind of crystal you will be making here.
Boil the water on the stove. Carefully measure out 1 cup (240 ml) into the heatproof measuring cup, then pour that water into the jar.
2. Stir in 3⁄4 cup (225 g) of Epsom salt. Mix thoroughly. If there is a little salt left at the bottom of the jar, that’s okay.
3. Add three to four drops of your favourite colour and mix well.
4. Place the jar in the refrigerator. Take a peek every few hours. What’s going on in there?
5. After 1 day, observe your crystals. Carefully scrape a large spoon against the bottom of the jar and observe the crystals up close. What do you notice? What shape did the crystals make?
6. Leave the jar in for 2 to 3 more days, then scoop the crystals that have formed. How are they shaped differently?
When you take the jar of crystals from your refrigerator, look carefully at it before disturbing it. You probably notice crystals clinging to the sides of the jar. Notice the patterns! At ﬁrst it may look like there’s just a layer of crust along the bottom of the jar. But when you scrape it with the spoon and remove it from the jar, you can see it’s much more intricate than a simple crust.
The ﬂat surfaces of the crystals are called facets. They form shapes, such as triangles, rectangles, and squares. Different kinds of crystals are used for different things. Quartz crystals are used in watches. When electricity from a battery buzzes through quartz, it vibrates. These vibrations keep time! Other crystals, such as diamonds, are used for more than just jewellery. Diamonds are so hard they can be used in saws that can cut through other hard rock.