MICHELE NORRIS, host:
This is ALL THINGS CONSIDERED from NPR News. I'm Michele Norris.
ROBERT SIEGEL, host:
And I'm Robert Siegel.
During the holiday season, we see a lot of images that cannot be found in nature: flying reindeer, sugarplum fairies and geometrically incorrect snowflakes. Well, one scientist has gotten tired of the snowflake problem.
NPR's Jon Hamilton talked with him about his efforts to correct the record.
JON HAMILTON: Thomas Koop is a chemist who thinks ice crystals are masterpieces of natural beauty. Unfortunately, he says...
Professor THOMAS KOOP (Bielefeld University, Germany): This beauty is sometimes corrupted.
HAMILTON: By artists, especially at this time of year, when a blizzard of snowflake images sweeps through advertisements and store displays and greeting cards. Koop, who is a professor at Bielefeld University in Germany, says the problem is that many of these images show ice crystals with five sides or eight sides. In other words, he says, they are scientific abominations.
Prof. KOOP: Since I'm a chemist, I know what the crystal structure of ice typically is. And therefore, I know that there's no way of having pentagonal or octagonal ice crystals. And therefore, such snow crystals shouldn't exist in nature - and they don't.
HAMILTON: Koop says snowflakes can assemble ice crystals into all kinds of complex shapes, but the crystals themselves will usually have six sides.
Prof. KOOP: The reason is because the molecular building blocks are water molecules. So there's only a certain way they can fit together. And what comes out is that they are always in a six-cornered shape, even at the tiniest molecular scale.
HAMILTON: Actually, water molecules occasionally form ice crystals with three or 12 sides, either half or double the usual number, but never five or eight.
Koop says he'd been pretty much ignoring this season's predictable onslaught of fake snowflakes until he saw a wintry ad for the online version of the scientific journal Nature.
Prof. KOOP: And that was entitled: For Anyone Who Loves Science. But all the snow crystals depicted in that advert were octagonal.
HAMILTON: Koop responded with a letter that offers a sort of snowflake manifesto. It calls for a campaign to melt away faux flakes. And it asks people to spend part of their holidays discussing the true beauty of science preferably over a mug of hot punch.
Koop's letter appears in the printed version of the journal Nature.
Jon Hamilton, NPR News.