Last year we saw how much fun we can have, turning plain old cornstarch into OObleck. How about we have some more? Mix up some OObleck from about 1 and 1/2 cups of cornstarch in a large bowl…. Check out my previous post for details. Now we can play!
Slowly dip your hand into the gooey stuff. It sinks, but it’s hard to take your hand out quickly (without taking all the OObleck and its container with you). Instead, lift your hand slowly and pretend its a monster from the lagoon!
Try sinking a plastic dinosaur or a toy car in your bowl of OObleck… anything you like, as long it washes up easy. What a great, gooey mess when you pull it all out . Make up a story about the slimy things you find in the green lagoon.
You can create eerie mixed-media art using OObleck. Pour a little of the stuff into six muffin cups. Add food color to make a rainbow in your tray. Spread out some newspaper and decide what you want to paint. Go crazy!
After a day of drying, the cornstarch coating starts to crumble. Take pictures to preserve your art.
Never pour OObleck down the drain!
The solid particles of starch will settle out of the water and clog your pipes. Instead, put the OObleck into a ziplock bag and throw it out with the garbage.
Here is some of the art we created:
How does it work?
When you mix cornstarch and water together, the solid bits of cornstarch get suspended in the liquid. The result is a liquid that changes into a solid when force is applied. Smack it and it feels hard. Press it down gently and it feels soft and runny.
That’s right, OObleck is what scientists call a colloidal suspension. When you punch the cornstarch-and-water mixture, you force the long starch molecules closer together. The impact traps the water between the starch chains to form a semi-rigid structure. When the pressure is released, the cornstarch flows again.
All liquids flow. But some flow more easily than others. Water flows fast. But honey is one liquid that flows verrrry slowly. Turn its bottle upside down and it takes a long time before the honey in the bottom starts to flow downwards toward the tip. If you heat the honey for a few seconds in your microwave oven, it flows faster. Most liquids react this way to heat and cold. In fact, that is how the expression, “Slow as molasses in January” comes about. OObleck is different, though. How fast it flows depends on force.
The best thing about using cornstarch in cooking is that it has almost no flavor. A close second-best thing about cornstarch is how it acts when it is heated. It gets thick… even when there is only a little of it in the mix. This makes it great in some recipes for pudding, jelly or sauce. Heat makes the starch molecules absorb liquid, swell up, and stick together. Cornstarch produces a glossy jelly-like texture, perfect for many Asian dishes. It’s also great in frozen desserts, because it holds its shape. When making a sauce, corn starch is best mixed into a bit of cold water, then whisked into the hot liquid. Cornstarch is not only fun to play with, it makes food fun to eat, too. Watch for future posts where I’ll be showing you how to make some cornstarch sauces and puddings that are simply delicious. Let’s get cooking!