Gwyneth K. Shaw Photo
It’s a simple recipe: Two parts cornstarch, one part water.
The mixture, gooey and fun, made Almando Harris’ eyes light up.
“It’s the ultimate quicksand!” he said, digging his hands into a plastic bowl filled with the cream-colored fluid.
What Almando (pictured above) held is called “oobleck” for demonstration purposes, a nod to Dr. Seuss’ classic tale of weird, blobby rain falling from the sky.
What it actually is, Tanay Lathia told him, is a non-Newtonian fluid — solid when you hit it, liquid when the pressure is removed.
“It basically doesn’t follow the regular rules,” Tanay, a 16-year-old student at Amity High School, told Almando, who’s 14 and a freshman at Hillhouse High School.
Since oobleck’s viscosity isn’t constant, Almando could roll the goop into a ball. When he stopped moving his hands, the liquid drained through his fingers.
In that moment was a lesson in nanotechnology. All around Almando and Tanay in a hallway outside Yale’s Davies Auditorium, other kids — and some parents — were getting a chance to wrap their hands, and their brains, around how super-small materials can mean big things.
Scientists and manufacturers are using non-Newtonian fluids to create better body armor and other flexible fabrics. Those ingredients might not be cornstarch and water, but oobleck is a way to drive home the concept.
This is the point of NanoDays 2012, now being observed around Connecticut, and the country, with special events, many of them hands-on and aimed at kids like the one Davies last Thursday night. The larger nationwide effort is shepherded by the National Informal Science Education Network, or NISE Net, a consortium of researchers and science educators.
NanoDays is all about demystifying nanotechnology, explaining its potential — and possible risks — in a basic way. The goal is to foster understanding, along with discussions about the pros and cons of various ultra-tiny materials.
Nanotechnology leverages the often-unique properties of super-small particles (a nanometer is a billionth of a meter) to create products with amazing qualities. These materials can make better batteries or lighter and stronger bike frames, as well as new medical instruments and medicines that can save lives. They’re increasingly common in consumer products, from “mineral-based” sunscreens to stain-repellent pants to boat paints that resist algae growth.
Larger gold particles help demonstrate the color changes that happen at the nanoscale.
Nanomaterials are believed to hold great promise for a wide variety of applications. Their ultra-tiny size also gives them different properties; scientists are struggling to figure out whether that can make them dangerous in the process, and how and why it happens.
Opinion surveys show that the average person doesn’t know much about these cutting-edge developments.
That’s where NanoDays comes in.
The event at Yale included a lecture from engineering professor Jan Schroers, who explained what nanomaterials are and some ways they’re being used. His own work focuses on metallic glasses —materials that have the durability of metal but the flexibility of plastic. He and his colleagues hope the metallic glass can be used to build more efficient catalysts, among other applications.
The event was put together by the Center for Research on Interface Structures and Phenomena, or CRISP, a partnership between Yale and Southern Connecticut State University and a National Science Foundation Materials Research Science and Engineering Center. Education is a key part of the center’s mission.
After the talk, guests fanned out among the hands-on exhibits. Their teachers for the evening included Yale research scientists and graduate students, as well as students like Tanay from Amity High who are in Deborah Day’s scientific research class.
Helen Zhao, 16, and Brian Liang, 17, both juniors at Amity, mixed corn oil and iron shavings to create a ferrofluid — basically, a magnetized liquid. They held a powerful magnet up to the side of the glass beaker, and like magic, the iron bloomed into a spiky, flower-like shape (click on the video to watch this in action).
Hilda Oki and her 13-year-old daughter, Jessica, gasped when they saw the transformation. Ferrofluids are more than just cool-looking, though: Scientists hope to use them to separate small particles, like blood cells and bacteria, more quickly. That could mean honing the ability to diagnose cancer in its earliest stages, when tumor cells are at a very low concentration.
Across the room, Yale senior research scientist Sharon Cui demonstrated how to tell whether a lotion containing zinc oxide is at the nanoscale or not. When rubbed on to black paper, a diaper cream stayed white, while a sunscreen became transparent. The transparency indicates that nanoparticles are involved, Cui said. Nano-sized zinc oxide and titanium dioxide are becoming more and more common in sunscreens, because the super-small particles allow the physical sun blockers to blend into the skin.
Sunscreen and diaper cream create a visual of what a nano-sized particle can do.
Christine Broadbridge, chair of Southern’s physics department, coordinates many of CRISP’s educational activities. She said it’s crucial that scientists like Schroers and Cui are involved in these kinds of programs, because they can help kids envision themselves as researchers. Adding high school students as demonstration leaders created moments like the interaction between Tanay and Almando — making a connection that’s about more than just chemistry or physics.
Day said she sees the same thing in her class, which mixes all grades. And when the students go to elementary and middle schools to share their projects, it’s even more fun.
“They inspire each other,” she said.
There are plenty of opportunities for inspiration around Connecticut over the next 10 days, as several museums — including the Yale Peabody Museum of Natural History — are offering similar demonstrations. (Read more about the events here.)
