Making crystals is a fun project for kids that can be done for a science project or science fair, or just for fun. You will need to use the microwave for this project, so an adult may have to help a very young child.

What Are Crystals?
Crystals are made of different things, but what they have in common is that they are beautiful, hard objects with a specific shape and pattern. Sugar and salt are examples of crystals. Some of the hardest crystals are diamonds. The substance the crystal is made of determines its shape. No matter the size of a crystal - big or small - it will keep the same shape. Some crystals can dissolve in water and some cannot. Salt and sugar are examples of crystals that dissolve in water and this project is based on that property.

Salt is a Crystal
In a salt crystal, the molecules line up into neat rows to make a smooth shape. If you put salt into water, the crystals dissove into molecules and float in the water. Then if you let the water evaporate, the crystal shapes will form again.

Sugar is a Crystal
Sugar behaves the same way as salt except is has a different shape. If you dissolve sugar in hot water and let it cool, the sugar molecules will line up to form crystals in the water too. It takes a while (a day or two) but it’s possible to make much larger sugar crystals than what you start with.

How to Make Sugar Cyrstals

You will need:

• String
• Jar
• Sugar
• Pencil

Tie one end of the string around a pencil. Cut the string the correct length so that if you lay the pencil across the top of the jar, the string hangs down into the jar almost all the way to the bottom.

Pour about 1 cup of water into the jar. Microwave the water in the jar until the water is slowly boiling. This should take about two minutes in most microwaves. (You could also boil the water on the stove and pour it into the jar.)

Very carefully set the jar on a table and slowly start adding sugar. The sugar will dissolve, disappearing into the water. Stop adding sugar when it stops disappearing into the water, or once you have added about 2 1/2 cups.

Lay the pencil on top of the jar so that the string hangs down.

Put the jar in a safe place and leave it alone for at least one whole day.

The crystals that dissolved (disappeared) into the water will reform on the string as the water cools. If you put too much sugar into the water, the whole thing can turn into one huge crystal.

Observe how each crystal has a uniform shape. They all look the same. This is because the molecules line up the same way every time.

Image Credit: Biology Big Brother, Flickr