On the last day of school one year, my older son, Curt, came home with a bag of slime.
No, it wasn’t the contents of a long-lost lunch bag, it was, as he explained to me in great detail, oobleck.
I watched him extract the green oobleck from the plastic bag, stretching it the length of his arm as he did so. Then he and his brother, Luke, proceeded to play with the oobleck for two hours.
Named for a slime in a Dr. Seuss book, “Bartholomew and Oobleck,” that had the power to gunk up a whole land, oobleck , besides looking like green gunk, has properties of both solids and liquids. Oobleck wiggles and jiggles like a liquid or jelly, but if you squeeze it in your hand, it will seem like a solid. In the scientific world, oobleck is called a dilatant, a substance that causes another to expand. If you slowly lower your hand into oobleck, it will sink, but it’s much, much harder to remove your hand without taking all the oobleck and its container with you. But in the real world, oobleck is just plain fun and easy to make with ingredients you probably have right in your pantry, perfect for a craft – or science experiment – on a hot summer’s day.
Food coloring (optional)
Mix 1 part water with 1.5 to 2 parts cornstarch. Start with 1 cup of water and 1 1/2 cups of cornstarch, then work in more cornstarch if you want a more ‘solid’ oobleck.
Mix for about 10 minutes to get the right consistency. If you mix oobleck in a plastic bag with a zipper lock, kids can “squish” it to the right consistency.
Mix in a few drops of food coloring if you want colored oobleck.
Squeeze or punch the oobleck. The cornstarch particles will not move out of the way quickly, so the oobleck will feel solid.
Mold oobleck in a container, but when you remove the mold, watch the oobleck lose its shape.