Moving slowly gives the cornstarch particles time to move out of the way. But dip your hand slowly into the mix, and see what happens-your fingers slide in as easily as through water. A quick tap on the surface of Oobleck will make it feel hard, because it forces the cornstarch particles together. But this simple mixture shows how changes in pressure, instead of temperature, can change the properties of some materials.Īpplying pressure to the mixture increases its viscosity (thickness). Other, more familiar substances change states (from solids to liquids to gases) when we change the temperature, such as freezing water into ice or boiling it away into steam.
Play around with it and find out how it acts differently from a normal liquid and a normal solid. Why is it so hard to get out of quicksand? Is it a solid? Is it a liquid? Can it be both? In this activity, you will make a substance that is similar to quicksand-but much more fun. From National Science Education Standards: Properties of objects and materials
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