Parts of the world are once again knee-deep in images of snow crystals for the Christmas and New Year festivities. Unfortunately, the grand diversity of naturally occurring snow crystals is commonly corrupted by incorrect 'designer' versions — as illustrated by the faux octagonal snowflakes depicted in a Nature online subscription advertisement and, ironically, captioned “...for anyone who loves science”.
The snowflake's natural sixfold symmetry stems from the water molecules' hexagonal crystal lattice, held together by a hydrogen-bonding network and the structural form of lowest energy under the ambient cold conditions. This hexagonal shape has been known since at least 400 years ago, when the astronomer Johannes Kepler published a treatise on the subject On the Six-cornered Snowflake (De nive sexangula Tampach; 1611), as a new-year's gift to his patron — modern editions are still available.
Beautiful photographs abound, including those taken by Vermont farmer Wilson A. Bentley starting in 1885 (W. A. Bentley & J. Humphreys Snow Crystals McGraw-Hill; 1931), or see http://www.snowcrystals.com. Why then do many artists invent their own physically unrealistic snow crystals?
We who enjoy both science and captivating design should aim to melt away all four-, five- or eight-cornered snow crystals from cards, children's books and advertisements, by enlightening those who unwittingly generate and distribute them. Let's welcome this as an opportunity to share a discussion about the true beauty of science over a mug of hot punch.