Amazing Oobleck

Oobleck is named after the strange material that falls from the sky in the Dr. Seuss book called Bartholomew and the Oobleck. The stuff we made on TV today may not be exactly what Dr. Seuss had in mind - but it's certainly strange stuff!

We often think we know the basic facts about things - like what's a solid, liquid or a gas? Today's oobleck experiment results in stuff that is hard to catergorize using these ideas. It's also a very easy experiment to make from materials in your kitchen.

To make oobleck you need only corn starch and water. There are different possible recipes and you can experiment on your own with proportions.

We used 1/2 cup of corn starch and 1/4 cup of water in our oobleck on Live at 11.

The basic observation you need to make to see how odd oobleck is, inolves how fast you interact with it. If you strike it hard and quickly - it resists like a solid would. If you place your finger gently on the surface it flows around it, seeming to offer no resistance at all.

Technically, this material is called a "non-Newtonian fluid" because it behaves this way. To understand this idea we need another word - viscosity, which is a measure of how much a fluid resists flow. A viscous liquid doesn't flow very easily. Most fluids resist flow more when more force is applied - apply twice the force and get twice the resistance. Non-newtonian fluids, like oobleck, don't follow this relationship. Quicksand is another example of a non-Newtonian fluid as are toothpaste and blood.

Links

Experiment Page - A nice experiment page with more on the oobleck experiment

Teachers Page - A page that scales up the oobleck experiment to be used by teachers

Oobleck Kit - A kit from Lawrence Hall of Science to provide even more ideas for oobleck experiments.