What makes cornstarch and water

A half-cup or so works fine for a couple of little scientists to play with, but you can make more to really dig into. Using about half as much water in another cup, pour it slowly into the cornstarch while stirring.

If the surface splashes like water when tapped, add some more cornstarch to get the right balance. Once your Oobleck is just right, dig in! Rest your fingers on top and then reach down deep.

Scoop it up with your fingers and play with it. You should know that if you try this activity and you are not smiling and messy with corn starch goo at the end, then you are definitely doing something wrong.

Also keep in mind that this is not just about fun, there is some pretty amazing science going on here. Notice that the goo does not splash or even move if you hit it quickly. Squeeze it hard and see what happens. How long can you get the strands of goo to drip? What happens if you let the goo sit on the table for a minute and then try to pick it up? How does it feel? Hows does it move? Try bouncing a ball on the surface of the cornstarch.

You get the idea — explore! Actual clean up of the goo is a snap. A bucket of warm water will quickly get it off your hands. It will brush off of clothes when it dries, and it is easily cleaned off surfaces with a wet rag. Important : Make sure you do not dump the goo down the drain — it can get caught in the drain trap and take the joy out of your day of science. Try to stir the Ooze quickly with a finger, and it will resist your movement.

Stir it slowly, and it will flow around your finger easily. Smack water with a spoon and it splashes. Smack Ooze with a spoon and it acts like a solid. Most liquids don't act like that. If you stir a cup of water with your finger, the water moves out of the way easily--and it doesn't matter whether you stir it quickly or slowly. Your finger is applying what a physicist would call a sideways shearing force to the water.

In response, the water shears , or moves out of the way. The behavior of Ooze relates to its viscosity , or resistance to flow.

Water's viscosity doesn't change when you apply a shearing force--but the viscosity of your Ooze does. Back in the s, Isaac Newton identified the properties of an ideal liquid.

Water and other liquids that have the properties that Newton identifies are call Newtonian fluids. Your Ooze doesn't act like Newton's ideal fluid. It's a non-Newtonian fluid. There are many non-Newtonian fluids around.

They don't all behave like your Ooze, but each one is weird in its own way. Ketchup, for example, is a non-Newtonian fluid. The scientific term for this type of non-Newtonian fluid is thixotropic. That comes from the Greek words thixis , which means "the act of handling" and trope , meaning "change".