The Science Behind the Fun of Shrinky Dinks

Growing up, I lovedshrinkydinks when my mom would get out the Shrinky Dinks, let me color them, and watch them bake down in the oven. When I saw a “Jewelry” Shrinky Dinks kit on clearance at a local bookstore, I knew it was time to introduce my daughter to the wonders of shrinking plastic.

Shrinky Dinks, for those who may not know, are thin sheets of plastic with designs on them that you color with provided colored pencils, cut out and then bake in the oven. When you bake them, they shrink down to about 1/3 of their size and much get much thicker. You definitely want to keep the oven light on for these! Not only to prevent over baking but so that you and your kids can watch them shrink and curl up, and then flatten and harden. All in about 3 minutes time-span.

Via Shrinky Dinks

After we were done creating our fun Shrinky Dink jewelry and hair barrettes, I got to thinking…what exactly are Shrinky Dinks. This is what I found out about the cool science behind the shrinking art:

The sheets of plastic you get in a Shrinky Dinks kit is polystyrene—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, 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, but 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—like when you pop a cookie sheet full of Shrinky Dinks into the oven.                            — blog

And Shrinky Dinks aren’t just for kids fun according to the article “Hack: Young Professor Makes Lab-on-a-Chip with Shrinky Dink and Toaster Oven” from  It’s a unique use for this art supply in the science lab.


If you’re a teacher, here’s a great Shrinky Dink project including scientific information, charts, and a sheet with student questions on it for classroom use:

You tell us:  Have you created Shrinky Dinks either yourself as a child or with your own children or students?  Was it all just for fun or did you talk to them about the science behind their art?  Let us know in the comments below or share your own ideas!

Disclosure of Material Connection:  Some of the links in the post above are “affiliate links.” This means if you click on the link and purchase the item, BJ Pinchbeck’s Homework Helper will receive an affiliate commission. Regardless, we only recommend products or services we use personally and believe will add value to our readers. We are disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: “Guides Concerning the Use of Endorsements and Testimonials in Advertising.


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Megan Fister is a website designer and manager of the Central Penn Adobe User Group in Harrisburg, PA. She loves technology and is married with a young daughter. She enjoys blogging on Homework Helper about technology and how it relates to children & education. Megan is BJ's sister and technical advisor to the Homework Helper Website.

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