WASHINGTON, Dec. 18, 2012 — For everyone with holiday visions of snowflakes dancing in their heads, the American Chemical Society, the world's largest scientific society, today issued a video explaining how dust, water, cold and air currents collaborate to form these symbols of the season. It's all there in an episode of Bytesize Science, the award-winning video series produced by the ACS Office of Public Affairs at www.BytesizeScience.com.
The video tracks formation of snowflakes from their origins in bits of dust in clouds that become droplets of water falling to Earth. When the droplets cool, six crystal faces form because water molecules bond in hexagonal networks when they freeze. It explains that ice crystals grow fastest at the corners between the faces, fostering development of the six branches that exist in most snowflakes. As snowflakes continue to develop, the branches can spread, grow long and pointy, or branch off into new arms. As each snowflake rises and falls through warmer and cooler air, it thus develops its own distinctive shape.
Source: American Chemical Society