Rip­ple Ef­fect

One physi­cist’s quest to find uni­ver­sal pat­terns in na­ture

The Walrus - - CONTENTS - by Patchen Barss

In his clut­tered lab at the Uni­ver­sity of Toronto, Stephen Mor­ris peers through the viewfinder of a cam­era pointed into a slot in an in­su­lated ply­wood box the size of a beer fridge. Jut­ting wires and hoses con­nect the box to wa­ter tanks, drains, and power sources. In­side, a mix­ture of wa­ter and flu­o­res­cent dye drib­bles from a hose onto a ro­tat­ing wooden spike dan­gling in the chilled in­te­rior. Each drop of the liq­uid grad­u­ally freezes, layer upon layer. An ob­ject slowly takes shape: a del­i­cate ici­cle. As the ta­per­ing col­umn of ice length­ens and widens, some­thing cu­ri­ous hap­pens: the smooth sur­face de­vel­ops ridges and val­leys. From stem to tip, the en­tire ici­cle grows a new, tex­tured skin.

Mor­ris is a physi­cist who spe­cial­izes in ge­o­mor­phol­ogy—the study of why nat­u­ral ob­jects are shaped the way they are. At fifty-nine years old, he has been search­ing for an ex­pla­na­tion for the rip­ples on ici­cles for more than a decade. If he can find an an­swer, he’ll be adding a small piece to one of the big­gest sci­en­tific puz­zles on the planet: Is there a uni­fy­ing the­ory that can ac­count for the struc­ture of all things — an­i­mal, veg­etable, and min­eral?

Some physi­cists search for a “the­ory of ev­ery­thing” by smash­ing sub­atomic par­ti­cles to­gether or by imag­in­ing the in­side of a black hole. Mor­ris chose an­other path, fo­cus­ing on “emer­gent prop­er­ties”—nat­u­ral be­hav­iours that could re­veal uni­ver­sal prin­ci­ples about how na­ture de­vel­ops or­der and com­plex­ity from seem­ing chaos.

Ici­cle rip­ples are an ex­am­ple of one type of emer­gent prop­erty. Na­ture of­fers many other cases where a flat state spon­ta­neously de­vel­ops pat­terns: dirt roads de­velop wash­board ruts as cars drive over them, syrup poured onto a mov­ing sur­face goes from smooth to un­du­lat­ing, and sta­lac­tites in caves “self-or­ga­nize” with rip­ples. Mor­ris has stud­ied them all. Un­der his gaze, these pat­terns of­fer up sto­ries about the math­e­mat­i­cal bones that give our uni­verse struc­ture.

In high school in Van­cou­ver, Mor­ris was a tin­kerer. He was hap­pi­est play­ing with com­put­ers and elec­tron­ics or work­ing on projects in shop class. His girl­friend, Mary de Bruyn, was more into lit­er­a­ture. Mor­ris went on to study physics at the Uni­ver­sity of Bri­tish Columbia and the Uni­ver­sity of Toronto, and de Bruyn, now his wife, stud­ied clas­sics. They feel they found par­al­lel paths. “The clas­si­cists are the physi­cists of the hu­man­i­ties,” Mor­ris says. “They don’t do things in trans­la­tion. They learn Latin and Greek. We used

to know a guy who could sight-read hi­ero­glyph­ics. He could look at a pic­ture of an an­cient tem­ple and just read it.” Mor­ris mas­tered a dif­fer­ent lan­guage, one cre­ated not by an­cient peo­ples but by na­ture. It is a vo­cab­u­lary of spi­rals and branches, of curved rivers and cracked earth, of poly­gons, frac­tals, waves, spots, and stripes. And ev­ery time he watches a wa­ter droplet freeze at the end of one of his ici­cles, Mor­ris inches closer to un­der­stand­ing where nat­u­ral or­der and pat­terns come from.

Geo­mor­phol­o­gists of­ten spend their time in the field, clam­ber­ing over rock for­ma­tions or study­ing ero­sion. But, as a physi­cist, Mor­ris is more at home in his jam-packed lab full of spools of coloured wire and bot­tles of chem­i­cals, hun­ker­ing over ex­per­i­ments that re­veal the essence of pat­tern for­ma­tion. Nat­u­ral ici­cles, for ex­am­ple, are sub­ject to in­con­sis­tent nat­u­ral el­e­ments, in­clud­ing rain and wind. Here in the lab, Mor­ris can con­trol vari­ables like tem­per­a­ture, air tur­bu­lence, and wa­ter flow, al­low­ing him to nar­row down the fac­tors that might trig­ger emer­gent prop­er­ties.his work strips away the mess and noise of the nat­u­ral world, leav­ing him with pre­ci­sion and sim­plic­ity.

Mor­ris re­calls the mo­ment he first dis­cov­ered the visual po­etry of pat­terns. In 1990, dur­ing a rou­tine ex­per­i­ment for his PHD at the Uni­ver­sity of Toronto, he was grad­u­ally in­creas­ing the elec­tri­cal volt­age run­ning across liq­uid crys­tal. Noth­ing hap­pened, and then, seem­ingly out of nowhere, rapidly whirling spi­rals ap­peared. He could see mul­ti­coloured pin­wheels whip­ping around in a highly or­ga­nized pat­tern. Mor­ris was stunned. “The mo­ment that I saw this changed my life, and I can­not be un­emo­tional about it,” he says. “I like the physics and I like the math, but my in­ter­est and my mo­ti­va­tion is be­cause I saw this thing.”

Mor­ris’s pin­wheels were more than just pretty—they also con­tained mean­ing. It was his in­tro­duc­tion to the idea that ex­pe­ri­enc­ing beauty could also get you closer to uni­ver­sal truths. A year or two later, he was heat­ing a thin layer of gas and no­ticed that, as the warm­ing gas sep­a­rated into hot and cold zones, it be­gan to self-or­ga­nize into some­thing that looked like an alien fin­ger­print or an ae­rial view of the world’s most elab­o­rate hedge maze. Mor­ris and his col­leagues called this pat­tern “spi­ral de­fect chaos,” and to this day, it is one of his favourites. He ex­hib­ited an en­larged but oth­er­wise un­al­tered ver­sion in an art show at Toronto’s

Project Gallery in

2013, and he wears a “spi­ral-de­fect-chaos sweater,” which de

Bruyn made for him, when he de­liv­ers talks on the art and sci­ence of pat­terns.

Ge­o­mor­phol­ogy re­search has many prac­ti­cal ap­pli­ca­tions — it can help de­ter­mine the size of an evac­u­a­tion zone for an avalanche or vol­cano or help ur­ban planners de­ter­mine whether a land­fill site will still be vi­able decades down the line. Mor­ris’s ici­cle re­search is of in­ter­est to en­gi­neers who deal with ice buildup on bridges or on power-line trans­form­ers. But the prac­ti­cal­i­ties are not what in­ter­est sci­en­tists like Mor­ris. “Ice buildup is a real con­cern,” he says, “but not my con­cern.”

Mor­ris helps run an art-sci­ence sa­lon and has col­lab­o­rated with pot­ters,

mu­si­cians, and other artists, who use his re­search as in­spi­ra­tion for their work. “Most of us folks in this field of study love the fact that our data is beau­ti­ful, but Stephen shows off at art events with im­ages from his lab,” says Karen Daniels, a physics pro­fes­sor at North Carolina State Uni­ver­sity. “This is mag­i­cal to me.”

Mor­ris’s work tends to pro­duce as much beauty as it does pure sci­ence. “The best con­fer­ence I ever went to was in the south of France,” Mor­ris re­mem­bers. “Ev­ery­body gave their tech­ni­cal talks and Pow­er­points. Then, at the end, we all just drank wine and showed each other pic­tures of our work. It was like show­ing baby pic­tures, ev­ery­body oohing and aahing. No­body asked what it was all for, be­cause it wasn’t for any­thing. It was for en­joy­ing the beau­ti­ful.”

In march 2015, Mor­ris launched an “ici­cle at­las,” an on­line data­base con­tain­ing more than 230,000 im­ages, videos, and 3D-print­able ici­cle files. The at­las, which gar­nered him in­ter­na­tional at­ten­tion in both me­dia and aca­demic cir­cles, was based on rev­e­la­tions he and his team had dur­ing tests in 2008. “We did our first ex­per­i­ments with tap wa­ter be­cause, you know, it’s just wa­ter,” Mor­ris re­calls. “We saw beau­ti­ful shapes with nice rip­ples on them, and we thought, ‘Okay, ev­ery­thing’s work­ing, let’s up our game a bit and use dis­tilled wa­ter.’ And what do you know. The ice is to­tally dif­fer­ent.” Dis­tilled wa­ter formed ici­cles as smooth and even as a skat­ing rink.

Mor­ris thinks the rip­ples must be caused by some­thing in the wa­ter, an im­pu­rity that af­fects the tem­per­a­ture at which it freezes as well as its flow, that breaks the uni­form sur­face and cre­ates the reg­u­lar rings. Mor­ris has tainted his ici­cle wa­ter with vary­ing amounts of salt, su­gar, cobalt chlo­ride, and other im­pu­ri­ties, in­clud­ing flu­o­res­cent dye that changes colour when it freezes, al­low­ing him to colour map ar­eas as they tran­si­tion from liq­uid to solid. Ev­ery ad­di­tion caused the rip­ple ef­fect. Mor­ris had solved one mys­tery but was left with an­other. Ev­ery im­pu­rity, at ev­ery con­cen­tra­tion, had the ex­act same ef­fect: the rip­ples were al­ways one cen­time­tre wide—never larger or smaller. Why does the self-or­ga­niz­ing mech­a­nism work in ex­actly the same way, in­de­pen­dently of so many vari­ables?

“I in­tend to solve it at some level, but even when you fail to solve some­thing, you still learn some truth,” he says. And as he chases this new puz­zle, he still pauses to en­joy what he is see­ing. “I’m try­ing to get peo­ple to see the world the way I do,” he says. “Study­ing pat­terns has been a source of fas­ci­na­tion, beauty, and won­der, but they also all mean some­thing. There is in­for­ma­tion in all of them.”0

Patchen barss has con­trib­uted to Sci­en­tific Amer­i­can and Nau­tilus. Flow Spin Grow: Look­ing For Pat­terns in Na­ture, his first chil­dren’s book, was pub­lished in Oc­to­ber.

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