You may know that many materials around us are made up of atoms. Some materials (for example Iron, Aluminium) are made up of just one type of atom. These materials are called "elements". Many other materials are made up of two or more types of atoms combined into something bigger, called "molecules". Water is a good example. Vinegar and soap are examples of more complex molecules.
Many of these materials can be in a solid, liquid or gaseous state, depending on the temperature. Water is normally liquid, but becomes solid (ice or snow) when the temperature drops below 0 deg. Celsius and becomes a gas (steam) when heated above 100 deg.C.
When they become solids, if the conditions are right, the molecules come together in complex, repeating patterns, called crystals. Snow flakes are an excellent example, but they are hard to see and observe because they melt in your hands!
But we can use a number of other materials and make some quite beautiful crystals to study at leisure. We have four experiments here, to get you started.
Crystals may take a few days to grow. So be patient - it will be worth the wait.
Adult supervision is required as you will be dealing with hot water. Please take care.
You will also materials such as Epsom Salts, which are not harmful, but do read the instructions on the packet.
You will need a few items that are not in the Starter Kit for this.
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
By using hot water, we were able to dissolve more of the Epsom Salts (Magnesium Sulphate) than we could with cold water. But when it cools, some of that Salt becomes solid again and form crystals. By cooling it quickly in the refrigerator, the growth happened quicker, but you can try just leaving it to cool naturally as well. See if it makes a difference to the result.
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:
Crystals from Sugar- Day 1
To start your crystals:
For this next step, you need an adult to help you.
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
Just like the first experiment, you started by making a saturated solution where no more sugar would dissolve. When it was heated up, the water was able to dissolve some more sugar and a super-saturated solution was formed.
Then, as the solution cooled, the sugar molecules in the solution began to join the sugar molecules on the sticks. The sugar on the sticks are called “seed” molecules, which the crystals a starting point.
Left for several days, the water in the solution gradually evaporates, leaving only sugar molecules behind. So more sugar molecules gradually join those already on the stick, forming even larger crystals. Now can you guess why you had to break up any crystals forming on the surface?
Because there is only one substance (sugar) all the dissolved molecules are the same (they are all sugar). So they all form the same shape of crystals and they all stick together. If you look carefully at the crystals formed on the stick, you may be able to make out the same basic shape being repeated.
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.
· Clean Glass jar
· Saucer or petri dish
· Nylon line
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
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.
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