How Crystals Form

0:00Salt, quartz and snowflakes are all crystals, but how do crystals form?

0:06Let us watch salt crystals form in a beaker of salty water.

0:11Zoom in to see the sodium and chlorine particles moving freely in the water.

0:17As the water evaporates, the particles get crowded closer together.

0:22Some of them meet and lock into place in a regular, repeating pattern.

0:27More particles join at the edges, one layer at a time.

0:33This regular, repeating pattern of particles is what makes a solid a crystal.

0:39The pattern shows on the outside as flat faces and straight edges.

0:44Salt particles line up in squares, so salt crystals grow as little cubes.

0:50Quartz grows the same way, as hot liquid deep underground slowly cools.

0:56Snowflakes grow in clouds, as water vapour freezes straight into ice.

1:02Each kind of crystal has its own pattern of particles, which gives it its own shape.

1:08So crystals form when particles lock together in a regular, repeating pattern.