If you’ve been shopping for Elmer’s Glue lately, only to be met with rows of empty shelf space, you’re on the butt end of a tween-age craze that is sweeping the nation. That craze is slime, a sticky polymer-based muck used for absolutely nothing other than occupying the restless hands and minds of the 8-12 year old set.
Slime is the ultimate post-modern concoction, devoid of content and very much function, at once malleable to whatever container it occupies and intractable to whatever creative content one might wish to work through it. Mix slime in a bowl and it soon morphs into a seething globular mass. Turn out slime on a countertop and it eventually spreads into a puddle with all the charm of fake vomit.
Of course, if you were out looking for Elmer’s Glue, there’s a good chance you already know something about slime. My first encounter with the substance came via my 11-year old daughter, Avery, who has spent the past two months frenetically mixing up slime on the countertop of our kitchen. She’d dump glue, and then either contact solution or Sta-Flo laundry starch into a plastic bowl and work it up into a rich blob. She couldn’t seem to help herself.
Avery’s methods are more witch than scientist, dependent on frequent micro-adjustments until the substance feels right. If she hits a snag in her slime making, she and her gunky fingers will grab a computer to check out YouTube videos or to FaceTime friends as they also work up batches of slime.
At Avery’s middle school, slime has become not just a fad but a commodity, to be sold or traded on her school’s nascent slime exchange. (Traded for what? More slime, of course.) “If I can sell this slime,” Avery announced to me after a bout of mixing, “I can use the profits to buy more ingredients.” Her obsessive logic, I noted to myself, was the same Walter White employed as he cooked up his favorite concoction in the desert of suburban Albuquerque.
Back in Homewood, the epidemic gripping elementary and middle schools is a benign one, but it’s no less an addiction. Slime’s method of exciting the brain’s pleasure centers is not chemical but tactile. Kids love squishing slime through their fingers, just as sure as they love snuggling woobies and smacking lacrosse ball sized wads of gum.
Slime’s ineluctability with children surely lies in its physical properties. It is on this point, physical property, that divergent preferences will arise. There are different types of slime, with their own qualities and their own devotees. There’s a bubble gum slime (speaking of which), that’s pretty much what it sounds like. There’s Nickelodeon slime, named after the kid’s TV show “You Can’t Do That on Television” and defined by its lime-green color and oobleck-like consistency. And then there’s Avery’s favorite, fluffy slime, a soufflé-like substance that gets its airiness not from egg whites but a can of Barbasol.
What gives different types of slime their distinct physical properties is a question not for your average slime fanatic, but for a scientist. So I found one. Her name is Dr. Amber Genau, and she is assistant professor of Materials Science and Engineering at UAB. Slime gets its sliminess in part, Dr. Genau explained to me one afternoon, from a polymer, polyvinyl acetate—a carbon-based chemical compound found in, you may have guessed, bottles of Elmer’s Glue. Because glue is mostly water, drying it out allows polyvinyl acetate’s stickiness to bind to objects like construction paper, wood, and, as another horrifying glue-based YouTube fad has revealed, blackheads.
Polymers like polyvinyl acetate are gooey because their atoms organize into long, spaghetti-like molecules. But gooiness isn’t the same as sliminess, which is why you can’t play with glue the way you can with slime. To effect this transformation you need another agent, Dr. Genau explained—a crosslinker. Crosslinkers connect polymer strands wherever they touch. Charles Goodyear figured this out when he vulcanized rubber, transforming it from something unreliably ooey-gooey into a substance that can be turned into tires.
Borax can cross-link polyvinyl acetate polymers. So can Avery’s substance of choice, contact solution, which contains sodium borate, the same active ingredient. However, the bonds formed between the polymer chains are weak, Dr. Genau explained. If you give them time, they slide, break, and reform, making slime ooze and flow. If you pull quickly, the slime snaps apart, breaking not only the cross-linked bonds but the polymer chains themselves.
Dr. Genau, it turned out, is something of an expert on slime and other pint-sized projects intended to explain to kids her concerns as a materials engineer.
As luck would have it, Dr. Genau had recently returned from a conference with educators and the topic du jour was, not surprisingly, slime. Inside her office sat a box filled with several dozen bottles of Elmer’s. So that’s where all the glue went, I mused.
Slime may be slippery, but it makes for a fairly solid jumping off point for evangelizing materials scientists, Dr. Genau said. She held up a large plastic bag—made from polyvinyl alcohol, a water-soluble polymer closely related to the stuff in Elmer’s glue. It’s the same sort of dissolvable plastic that holds the detergent in Tide and Cascade pods. Hospitals use these bags to safely hold and eventually wash blood-and-guts encrusted scrubs because they can toss the whole bio-hazardous thing, bag and all, in the washer.
Polymers can be very useful. They can hold chemotherapy cocktails for cancer patients, become milk jugs and PVC pipe. And they can be not so very useful. As I was leaving Dr. Genau’s office, she handed me a hydrophilic polymer pellet that could be dropped in water to grow into golf-ball sized orbs of ectoplasm. These pellets serve roughly the same purpose as slime, which is to say, not much of one.
Slime indeed does present a metaphysical challenge. Its substance is, arguably its accidental property, sliminess. Its function is to impart these accidental properties to the senses and not much else. Its cause is born out of the desire for the experience of its properties. Its ultimate end is usually the drain of a kitchen sink. Throughout its questionable lifecycle, the average glob of slime will go through much. Most often, I notice, it is either in some phase of coming into existence or relaxing in a Rubbermaid tub.
If Avery’s slime making habits are any indication, it will undergo frequent transformations, often through the addition of hand lotion (which imparts a lustrous sheen) or pigment from water-soluble markers. It can even be separated into smaller globs and worked into fresh batches of slime to give them body. In this regard, slime can be a bit like starter material for sourdough bread.
Slime, as inert as it might appear, surely teems with rich bacterial civilizations that could take down an entire household for a week. But in another sense, we’re its host. Through us, slime replicates its proprieties, works the idea of itself through tiny human hands until it actualizes. The process of coming into being is happening thanks to YouTube. It’s happening through FaceTime conversations. It’s happening through Dr. Genau’s lesson plans and in the halls of Homewood Middle School.
And it’s happening again and again and again, as the idea of slime takes possession of young hands and minds and makes itself. Slime begins its journey toward being not in the spaghetti that is polyvinyl acetate but in the imagination—the old noodle. Slime has attached itself to us and it may be oozing its way toward you now. You might want to stock up on some glue.•