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1. Let's Start with Small Crystals from Epsom
You will need a few items that are not in the Starter Kit for this.
- Some Epsom Salts. You can get this at a Chemist or Supermarket, probably with the bath salts.
- A drop of food colouring.
- Pipette or dropper (provided)
- Some aluminium foil.
- A glass tumbler that can hold about 1-2 cups of liquid.
Start by putting 1/2 cup of hot water into the glass container. Add 1/2 cup of Epsom salts and stir for at least a minute.
The Epsom Salts will dissolve as you stir the solution, but there will come a point where nothing more will dissolve and there will be a little left at the bottom. This is called a "saturated" solution.
Now add a couple drops of food colouring using the dropper provided. This is simply to help you see the crystals. They also look beautiful!
Cover the tumbler with aluminium foil place it in the refrigerator.
After several hours you will see crystals deposited on the bottom of the glass. You can pour out the remaining liquid and study the crystals. Make notes of what you see, so that you can compare with other experiments later.
Crystals forming at the bottom of the tumbler:
Crystals from Epsom
2. Decorative Crystals from Sugar
In this experiment we will use white sugar to grow crystals on chopsticks or something similar. They can be quite attractive and even used as decorations!
You will need a few items that are not in the Starter Kit:
- Some white sugar
- A few drops of food colouring - more than one colour if possible
- A small paper plate.
- Baking paper
- Saucepan
- Stove
- Several small clean glass jars (If you use empty jam jars or something similar, that has been well washed and the labels removed, you will be able to keep the crystals as long as you like)
- Wooden chopsticks, kebab skewers or similar
- Some glue
Crystals from Sugar- Day 1
To start your crystals:
- Put a little sugar on a paper plate or saucer
- Apply a little glue on the narrow end of the chopsticks and roll that end in the sugar, tapping it gently to remove any excess.
- Now set the sticks out on some baking paper, to dry.
Next:
- Pour about a cup of water into the saucepan and add about 50 g (about 2 Tablespoons) of sugar and stir it well until the sugar is dissolved.
- Now add more sugar about 50 g at a time and keep stirring until you reach a point when no more sugar will dissolve and some some undissolved sugar remains at the bottom of the saucepan.
- This is called a saturated solution.
For this next step, you need an adult to help you.
- Heat the saturated sugar solution on the stove, until it boils, stirring all the while.
- Turn the heat down to low and keep stirring. You will notice the undissolved sugar now dissolving in the hot liquid. Keep heating gently and stirring until everything is dissolved.
- This is now a super-saturated sugar solution.
- Keep cooking the liquid and stirring it until it becomes clear. Turn off the stove as soon as it begins to look clear.
- Now allow the pan to cool until the sugar solution is still slightly warm.
- Pour the sugar solution into the glass jars. Fill each about 2/3 full.
- Add a few drops of food colouring into each jar and stir. You can try as many colours as you like.
- Wait for the solution to cool a little more, then place a couple of the sugar-coated sticks that you prepared earlier, in each jar.
- Keep the jars in safe place where they will not be disturbed, but you can view them easily.
- Check them every day. If you find large crystals forming on the surface, just stir the liquid gently with the sticks to break them up.
You will see crystals begin to grow on the sticks. The little bit of sugar you stuck on with glue helps the crystals get started. After about a week, you will should see a lot of colourful crystals growing on the sticks.
Crystals from Sugar
3. Crystals from Alum: large crystals
Manufacture large crystals that look like gems from Alum: potassium aluminium sulphate is a chemical compound: the double sulphate of potassium and aluminium, with chemical formula KAl(SO₄)₂. It is commonly encountered as the dodecahydrate, KAl(SO₄)₂·12H₂O.
Materials required:
· Alum
· Clean Glass jar
· Saucer or petri dish
· Pencil
· Nylon line
Protocol:
- Slowly add alum to 1/4 cup of very hot tap water in a glass jar.
- Stirring to dissolve and keep adding the alum until no more will dissolve (saturated solution).
- Pour a little bit of this solution (clear solution) into a shallow petri dish or saucer and let it sit undisturbed overnight.
- The next day you would see small crystals growing in the dish.
- carefully pour off the solution.
- Make another saturated alum solution with about 1/2 cup of hot water.
- Pour the solution (clear solution) into a clean glass jar.
- Using a pair of tweezers remove the large and good-looking crystals from the saucer (from Step 4) and use as a seed crystal.
- Tie one end of Nylon line to the seed crystal. This can be tricky.
- Tie the other end of the Nylon line to a pencil, then set the pencil across the top of the jar so the seed crystal is suspended in the middle of the alum solution (No touching the sides or bottom of the jar).
- Adjust the length of the Nylon line accordingly. (Note: if your seed crystal starts to dissolve, that means your solution is not saturated enough.
- Cover the jar with a paper towel.
- Let the crystal grow until ood size.
- Take the crystal out of the solution and set it on plastic surface to dry.
What Happened:
The small crystals that formed in the saucer by nucleation. Nucleation is the first step in the formation of a new structure via self-assembly or self-organization. A few alum molecules joined together in a crystal pattern in the solution. Other alum molecules continued to join them until enough molecules gathered to become a visible crystalline solid and continue to grow in the solution.
As it forms number of small crystals, they would all be competing for the remaining alum molecules in the solution and would not be able to form very big crystals. Instead, you took one crystal and used it as the only nucleation site in the solution and it was the only site for the alum molecules to join together, so the crystal could grow quite bigger.
Crystals from Alum
4. Crystal Decorations: Crystals from Borax
In this experiment you use a chemical called Borax to grow crystals. Then you can use them as attractive decorations. Borax is a natural mineral with a chemical formula Na₂B₄O₇. Borax also is known as sodium borate, sodium tetraborate or disodium tetraborate. Borax is a component of many detergents and cosmetics. It is used to make buffer solutions, use as fire retardant and as an anti-fungal compound.
Materials required:
- A glass jar (~550ml Jam bottle)
- Cleaning brush (Small)
- String
- Scissors
- A pencil
- Water
- 1-cup measuring cup
- Tablespoon
- Borax
- Food colouring
- Glow-in-the-dark paint (optional)
- Ribbon (optional)
Protocol:
- Tie a piece of string to small cleaning brush. Tie the other end around the middle of a pencil.
- Hang the brush in the jar with the pencil resting across the mouth of the glass jar. Make sure that it hangs without touching any part of the jar. Take it out of the jar and set it aside.
- Pour 400ml of boiling water in the jar (the jar will be very hot) and set it on a heat-safe surface.
- Add 5-10 drops of food colouring to make coloured crystals.
- Add several tablespoons of Borax. Stir the Borax solution with a spoon until as much of it dissolves as is possible. If you don’t see any tiny pieces of Borax floating around in the jar, add another tablespoon and stir. This will make a saturated solution.
- Hang your brush in the jar so that it is completely covered in the solution and leave it overnight.
- Gently remove the crystal-covered brush in the morning and let it dry by setting it in a dry waxed paper.
What Happened
Borax is a chemical that forms crystals when the conditions are right. Once the crystals started to grow on the brush, more and more crystals formed around them. Ice crystals are real snowflakes are made of only of water not like these Borax crystals, but they do look similar and they both are glittering when light shines on them. The difference is that snow is formed when water vapor in clouds freezes and falls to the ground as snowflakes. Frost is another form of ice crystal.
Crystals from Borax