Do the sounds of dripping eaves and squelching slush heapsmake you just the tiniest bit sad about winterending? No more crunchy snow underfoot, no more picturesque flakes drifting past yourwindow? Relegating allyour sweaters and thick socks tothe back of the closet?

Just me?

For anyone else who wantsa taste of winter in the off-seasonor for anyoneliving in less wintry climesnow theres the Icicle Atlas.

Over four years, researchers at the University of Toronto grew and photographed icicles. Theymay seem mundane when theyre sprouting from your gutters, but icicles are mysterious in how they form. Their shapes emerge from a complex set of interacting factors: air flow, water flow, the icy foundationstheyve already built.

The scientists grew 237 icicles on an icicle growing machine with a slowly rotating dripper nozzle. The apparatus turnedabout once every four minutes, ensuring thatconditions were the same all aroundthe icicle. This is the same reason you rotate the meat in a BBQ; to make all sides the same, says Stephen Morris, the physicist who supervised the project.

With their icicles rotisserie-ing away, the researchers tweaked several variablestemperature, air flow rate, water flow rate, the makeup of the waterand watched the effects.

The most interesting variable turned out to be water purity, Morris says. Impure water icicles have regular ripple patterns on their sides. Even a tiny bit of salt inthe water created the ridgedshape.

Whats more, Morris says, We still cant explain the ripples. Scientists dont know why small impurities are enough to create the ridges, or why theyrealways about 1 centimeter wide. They dont even know why the ripples exist in the first place.

All of the physicistsresults are available on the Icicle Atlas homepage: research papers by Morris and his former PhD student Antony Chen, photos and videos of the icicles, and entire spreadsheets and tables of data. The researchers want the information to be there for anyone who wants it. That might include scientists studying fluid dynamics; artists and modelers; and eventhe occasional person who justmisses winter.

Original post:
Icicle Zen (Plus Science)