Grow an Ice Crystal
Every single snowflake that has ever fallen has six sides, never five, never seven, always six! Glaciologists (scientists who study ice) have figured out exactly why, and you can grow your very own ice crystal to see it happen.
What You'll Learn
- Why ice crystals always form with six sides - How water molecules lock together to build ice - How temperature changes the shape of ice crystals - How to grow and observe your own ice crystal at home
Why Six Sides?
A single drop of water is made of tiny molecules shaped like a wide letter V, with an oxygen atom and two hydrogen atoms. When water freezes, these V-shaped molecules link together, and the angle of that V naturally causes them to lock into six-sided patterns, like tiny building blocks that only fit together one way. That's why every ice crystal and snowflake grows a six-sided (hexagonal) shape.
Temperature Changes the Shape
Glaciologists have discovered that the exact shape of an ice crystal depends on the temperature and moisture in the air. Around 27°F (-3°C), flat six-sided plates tend to form. Around 5°F (-15°C), long, feathery, branching arms form instead, the classic snowflake shape. This is why no two snowflakes look exactly alike, even though they all follow the six-sided rule.
Fill a clear jar with hot water, stir in sugar until no more will dissolve, drop in a string with a paperclip weight, and leave it somewhere cool and undisturbed for 3-5 days. You'll see crystals growing on the string, just like ice crystals grow in a cold cloud!
Where Glaciers Fit In
When snow crystals pile up in cold places like Antarctica or high mountains, the weight of new snow squeezes the older snow below into solid ice over many years. Enough of this squeezed ice forms a glacier, a giant, slow-moving river of ice. Some glaciers in Antarctica are over 2 miles (3.2 km) thick, built from countless six-sided snow crystals packed together.
Match each term to what it means.
Terms
Definitions
Drag terms onto their definitions, or click a term then click a definition to match.
Why do ice crystals always form with six sides?
What mainly determines whether an ice crystal grows as a flat plate or a branching snowflake arm?
Grow and Sketch Your Crystal
Follow the sugar-crystal jar experiment above. Each day, sketch what you observe growing on the string. On the final day, count how many sides your biggest crystal has and compare it to a picture of a real snowflake.
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