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Ice crystal

earth science Maturity 5-7 Next article →

Ice crystals are solid water in many different shapes.

Ice crystals 3
Ice crystals 3

Most of them have six sides. This pattern is called hexagonal symmetry. You might see them as columns or flat plates. Some look like needles or even branching stars called dendrites. These crystals are very important for our weather. They help create clouds and beautiful light shows in the sky.

How do these shapes form? It starts with tiny water molecules. These molecules have a V shape. They join together in a hexagonal lattice. A lattice is just a repeating pattern of shapes. This happens through depositional growth. This is when water vapor turns straight into ice. Another way is called nucleation. This is when water collects on small particles and freezes.

Hexagonal Ice Crystals
Hexagonal Ice Crystals

When more vapor freezes onto an existing crystal, a snowflake is born.

Sometimes, ice crystals look different than the usual six-sided shapes. This can happen in the upper atmosphere. High up, water can be supercooled. This means the water is below freezing but stays liquid. When it finally freezes, it creates stacking defects. These defects make crystals with trigonal or cubic symmetry.

Snow crystals
Snow crystals

Scientists have even found square ice crystals. These form when water is squeezed between layers of graphene. High pressure and a force called van der Waals force drive this. This creates a new kind of ice.

Ice crystals change how the sky looks to us. They make up cirrus clouds and ice fog.

Refraction-of-light Winter-Halo-2020
Refraction-of-light Winter-Halo-2020

They also create light effects like diamond dust. You might see a halo around the sun. This is a 46° halo. It happens through a process called scattering. Scattering is when light hits the crystals and bounces off. Crystals rubbing together can even produce lightning. Most crystals fall horizontally, but electric fields can change their path.

These crystals are also a big deal for travel. Ice can be a hard job for airplanes. Crystals can melt on a warm aircraft surface. Then, they refreeze into ice. This can damage an airplane engine. Because of this, the aerospace industry is designing special radar. This radar helps find ice in the air. Weather experts also use radar to see different types of rain. They look at how wide or tall a droplet is. Since ice crystals are wider than they are tall, radar can find them.

Ice crystals 3
Ice crystals 3
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🖼️ Images & Media (5)
File:Ice crystals 3.jpg
Ice crystals 3.jpg
File:Hexagonal Ice Crystals.svg
Hexagonal Ice Crystals.svg
File:Снежинка на разноцветном фоне.JPG
Снежинка на разноцветном фоне.JPG
File:Refraction-of-light Winter-Halo-2020.jpg
Refraction-of-light Winter-Halo-2020.jpg
File:Snow crystals.jpg
Snow crystals.jpg
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