How crystals grow — Chemistry, 7–10 years

A crystal grows when particles arrange themselves in a repeating pattern. Salt and sugar crystals show this clearly, and their flat faces and regular shapes come from the way their particles fit together.

A repeating pattern

In a crystal, tiny particles are arranged in an orderly pattern that repeats again and again. As more particles join, the pattern grows outwards. That is why a crystal can have straight edges, flat faces and a recognisable shape instead of looking like a random lump.

Why the pattern matters

People noticed that salt, sugar and minerals often form regular shapes, but a shape is not just decoration. It gives clues about how the particles inside are arranged. Studying crystals helps scientists identify substances and understand why they behave in particular ways.

Growing salt crystals

Stir salt into 100 millilitres of warm water until no more dissolves. Leave the dish somewhere safe so some water can evaporate. After several days, salt particles meet and settle into a repeating pattern, making small crystals on the dish and along the string.

Not every shiny solid is a crystal

It is easy to call any shiny piece a crystal because crystals often sparkle. The important clue is not shine but the repeated internal arrangement of particles. Glass may look like crystal, yet its particles do not form the same orderly repeating pattern.

In rocks and technology

Quartz crystals help form many rocks, and salt crystals are found in dried-up sea water. Carefully grown crystals are also used in watches, cameras and some electronic devices because their regular structure gives them useful properties. Crystal shape can matter in medicines too.

Keep exploring

Other languages

Loading MyLeoNes™…