Build a crystal lattice

• Mini marshmallows, sweets, or modelling clay (these will represent atoms or ions)
• Cocktail sticks, toothpicks, or wooden skewers (these will represent bonds between particles)
• A flat surface for building
• Paper and pencils for recording observations

• Ask an adult for help when using cocktail sticks or toothpicks.
• Do not eat materials that have been handled during the experiment.
• Keep small pieces away from young children and pets as they can be a choking hazard.
• Wash your hands after completing the activity.

 1) Build your first unit cell

A unit cell is the smallest repeating section of a crystal structure.

Start by connecting your marshmallows or modelling clay pieces to create a simple shape, such as a cube.

This small structure is your unit cell.

2) Repeat the pattern

Now copy your unit cell again and again.

Connect the units to create a larger structure.

Notice how a small repeating pattern can create a much bigger organised arrangement.

3) Change the structure

Try building different arrangements.

Ask yourself:

• What happens if you change the position of one particle?
• Can you make a structure that is stronger?
• Can you create a pattern that repeats differently?

4) Test your crystal

Carefully test your structure.

Can it:

• Support weight?
• Stay standing?
• Be made larger without collapsing?

Think about how the arrangement of tiny particles affects the properties of the material.

Everything around us is made of tiny particles called atoms, ions and molecules. In many solid materials, these particles are not arranged randomly. Instead, they organise themselves into a repeating three-dimensional pattern called a crystal lattice.

A crystal lattice is like a building plan that repeats over and over throughout a material. The smallest repeating part of this pattern is called a unit cell. Just as repeating a single brick pattern can create a large wall, repeating a unit cell creates a complete crystal.

Different materials have different crystal lattices because their particles arrange themselves differently. For example, table salt forms a cubic crystal structure because sodium ions and chloride ions arrange themselves in a regular repeating pattern.

The way particles are arranged affects the properties of the material. A change in the crystal structure can influence:

• Strength
• Hardness
• Melting point
• Electrical properties
• Shape

This is why two materials made from similar particles can behave very differently if their crystal structures are different.

Scientists study crystal lattices to understand how materials work and how new materials can be designed. By understanding how particles arrange themselves, researchers can develop improved medicines, batteries and advanced materials.

 Growing crystals at home is just the beginning.

At CrystoGen, we develop software that helps scientists understand how crystals grow before they even enter the lab. Our simulations support research across pharmaceuticals, advanced materials, batteries and many other industries.

Every crystal starts small... and so does every scientist.

We'd love to see and share what you've grown, so send pictures of your crystals to us at team@crystogen.org!