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How to Make Oobleck | Fun Science Projects

a green slime splat.
Like Dr. Seuss' oobleck, non-Newtonian fluids get thicker as they are deformed, say by someone running across the fluid.
Credit: apartment, Shutterstock

Want to have fun with physics and even "walk on water"? Try making a mixture of cornstarch and water called oobleck. It makes a great science project or is just fun to play with.

Oobleck is a non-Newtonian fluid; it has properties of both liquids and solids. You can slowly dip your hand into it like a liquid, but if you squeeze the oobleck or punch it, it will feel solid. The name oobleck comes from the Dr. Seuss book, “Bartholomew and the Oobleck.” In the story, oobleck, a gooey green substance, fell from the sky and wreaked havoc in the kingdom.

Making oobleck is easy. Here's a recipe:

Oobleck ingredients

  • 1 part water
  • 1.5 to 2 parts cornstarch
  • Small amount of food coloring (optional)

Mix ingredients

  • Start with the water in a bowl (or wading pool!) and add the cornstarch a bit at a time.
  • Keep stirring until it has a gooey consistency. You may want to use your hands.
  • When the oobleck is just right, slowly add food coloring, if you want. This can be a challenge to get it mixed properly.
  • Play with it.

Things to do with oobleck

  • Grab a handful and squeeze it. Let it ooze through your fingers.
  • Make a puddle and quickly drag your fingers through it.
  • Put it into a plastic container and shake it or quickly bump it against a table.
  • Jab at the oobleck and then slowly let your finger sink in.
  • Roll some oobleck into a ball. It becomes solid, but when you stop moving it, it will melt back into your hand.

Some science projects use oobleck. Experiments you can try include:

Put some oobleck on an old speaker and watch it dance:

Or, put it in a cookie sheet on top of a speaker:

Put a lot of it in a kiddie pool and walk across it:

Tips

  • Store in an air-tight container. Mix occasionally.
  • If you put in food coloring, you may notice a little bit of color left on your hands after washing. Don't worry. It should go away in a day or two.
  • Anything put into the slime can be washed with soap and water.
  • To dispose of the oobleck, mix it with a lot of hot water to make a very loose slurry. Pour a small amount into the drain while the hot water is running.
  • Oobleck when dried can be easily vacuumed.

Warnings

  • Don't drop oobleck on a couch, deck, or sidewalk. It's hard to get off.
  • Oobleck isn't poisonous, but it tastes awful. Wash your hands after playing. Make sure children are supervised.
  • Wear old clothes, as oobleck tends to get messy.
  • Don't worry too much if it gets on something; it will come out with a little water.
  • Lay a couple newspapers on the floor so it doesn't get all over the floor or table.
  • Oobleck may solidify if it's not kept wet. If it hardens, just throw it away.
  • If oobleck is left out too long, it will dry out and turn back to cornstarch.

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Tim Sharp, Reference Editor

Tim Sharp

Tim Sharp is the Reference Editor for Live Science. He manages articles that explain scientific concepts, describe natural phenomena and define technical terms. Previously, he was a Technology Editor at nytimes.com and the Online Editor at the Des Moines Register. He was also a copy editor at several newspapers. Before joining Purch, Tim was a developmental editor at the Hazelden Foundation. He has a journalism degree from the University of Kansas. Follow Tim on and @TimothyASharp
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