Explorit Science Center: Experiment with corny chemistry

Special to the Enterprise

This time of year you may find yourself with a little extra time on your hands and a few extra baking ingredients cluttering up your pantry. Why not bust out your chemist’s curiosity and whip up some organic plastic in your microwave?

You will need: a microwave-safe container (a ceramic cup or a zipper-lock bag work just fine), a stirring spoon, measuring spoons, water, corn starch, corn oil, food coloring and a microwave.

Start by adding a tablespoon of cornstarch to your container. Cornstarch is a powdery white substance derived from the kernels of corn. It’s one of the many products that can be made from corn.

Cornstarch is usually used in cooking to make gravy and sauces thicker. When cornstarch is heated up, its molecules form long chains that mesh with each other, creating a grid that holds all the other molecules of your food close together. It’s going to form the base of our organic plastic.

Next, add two drops of corn oil and 1 1/2 tablespoons of water to the cornstarch. As you mix it all together, observe what’s happening in your container. You’re probably noticing the formation of a thick, gooey liquid.

The water and oil are giving the cornstarch particles something to move around in so they can start forming those long chains of molecules. Scientists call such substances “polymers.” Polymers are great at helping things stick together.

Once your mixture is stirred together, add a couple of drops of food coloring and pop it in the microwave for 20-25 seconds. If you’re using a zipper-lock bag, don’t close the bag all the way; leave a small opening for steam to escape.

As your mixture heats up, the polymers from the cornstarch will start grabbing onto each other and making your mixture stick together. After about 20 seconds, remove it from the microwave, but be careful as it will be hot.

As you let it cool for about a minute, observe your mixture again. How has it changed? What does it look like now? What does it remind you of? What could you use it for?

After a minute or so, your organic plastic may still be a little warm, but it should be cool enough to handle. Roll your plastic into a ball or mold it into any shape you like. You could even make an organic plastic sculpture!

Scientists have been using corn to make plastic for all kinds of things from packing peanuts that keep packages from getting broken to plastic utensils for picnics. Organic corn plastic is different from other kinds of plastic because when it gets thrown away it’s made of all natural things that will break down. Other plastics like plastic bags will stay in our garbage for a long, long time and contribute to polluting our environment.

But your organic corn plastic ball or sculpture is all-natural and environmentally friendly!

Explorit’s coming events:

* Winter break: Explorit’s “Beyond the Table” exhibition will be open from 1 to 5 p.m. through Monday and Jan. 2-6.

* Tis the Season of the Spider: Make spider hats on Saturday and Sunday; the activity is free with paid admission to the regular exhibition.

— Explorit Science Center is at 3141 Fifth St. For more information, call 530-756-0191 or visit www.explorit.org, or “like” Explorit on Facebook at www.facebook.com/explorit.fb.