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Introduced in 1973, Shrinky Dinks had kids (and crafty adults) creating artwork on flexible sheets of plastic. When they were popped into the oven, they would magically shrink down to approximately 1/3 their original size. You were then supposed to play with whatever it was you made. But frankly, the entertainment value was all in coloring pictures of your favorite cartoon characters. Then you watched them crinkle up in the oven and then mysteriously lie down flat again.
But, magic isn't behind the toy's quirky properties. The sheets of plastic you get in a Shrinky Dinks kit is polystyrene. It's the same stuff as recycled plastic #6, which is commonly used for those clear clamshell containers you see in cafeterias. When manufactured, raw polystyrene is heated. It is rolled out into thin sheets and then rapidly cooled so that it can retain its shape.
By nature, the polymer chains within the polystyrene are bunched up and randomly clumped together. The heating, rolling and cooling process forces them to straighten out and get into a more orderly configuration. All the polymers want to do is bounce back into their more disorderly arrangement and they are able to do this when the polystyrene is heated again. It's like when you pop a cookie sheet full of Shrinky Dinks into the oven. For marketing purposes, the term "magic" works pretty darn well.
Furthermore, Shrinky Dinks are moving beyond their reputation as a kid's toy. Scientists are finding practical applications for the whimsical sheets of plastic-namely, according to a recent study from Northwestern University, in the world of nanotechnology. It's a branch of science that looks at the properties of materials on very small scales. For instance, glass, usually used to insulate electronic material, conducts electricity on the nano scale. Metals like gold can appear red or blue. In the real world, this branch of science is being used in the manufacture of solar cells. It's also being used to make high-density displays and chemical sensors.
Scientists who want manipulate the properties of certain materials work with nano-scale patterns printed with those materials. However, the printing process takes time. It is grievously expensive. New printing technology can print those patterns on Shrinky Dink plastic. Scientists can then shrink the plastic so they can further their nano-scale investigations. The technology is cost effective to the point where any laboratory can independently produce as many copies of these test patterns as they need. Crafty, no? There really is a Shinky Dinks kit for everyone.
Source URL: https://www.tweentribune.com/article/tween78/science-behind-shrinky-dinks/