Pushing the mixture slowly with our hands, a spoon or a stick caused it to flow. Tipping the bowl made it flow like a liquid.

But, we could pick up a clump of it as if it were solid. Then the clump would liquefy and start to drip and run off our hands. We could then break off a piece of the stream as if it were an icicle suspended from a roof top!

The cornstarch and water mixture reminded us somewhat of the fine beach sand that can be found just at the water's edge by the ocean. When you stomp on it the sand feels hard, but if you gently press your feet onto it the sand gradually gives way and your feet sink and disappear. Likewise with the cornstarch and water mixture,when we stabbed at it quickly it felt hard and our fingers didn't even get wet, but when we gently pressed our fingers onto the surface the mixture parted easily and our fingers disappeared inside.

When we placed a small stone or a penny on the surface of the mixture the object would slowly sink. Objects such as wood or cork remained on the surface.

It seems that the cornstarch and water mixture behaves like a liquid when still or moving slowly, but becomes very viscous, almost like a solid when poked, pressed, or stirred abruptly. A liquid like this that becomes more viscous when agitated is called dilatant.

		Digging Deeper
		Find out more about
	properties of liquids.

Try this...

• Heat the mixture and then let it cool. Does it now behave differently?
• Freeze it and let it thaw. Has it changed?
• Make a mixture with more water. Try it with less water. How are they different?
• Share your observations and explanations.