I’ve written before about cornstarch goop (aka “oobleck”). It’s a mixture of cornstarch and water that changes state from solid to liquid as you stir it, pick it up, or press it in your hands.
Another way to use this material is to freeze it. Frozen goop is truly a mystery material. Children don’t have any prior knowledge or experience to base their actions on, so they approach this material with curiosity and scientific exploration.
I prepared the goop by mixing cornstarch and water, then pouring it into small plastic cups with some liquid water color paint. I put the cups in the freezer overnight. Getting the frozen goop out of the cups is tricky – you have to let them defrost a little bit first. I put the cups on the heater vents, but you could also dip them in warm water to loosen the goop from the cup.
Once I got the goop out of the cups, I put it into the sensory table with some various small cups and scoops.
It looked a little like ice cream, even though after touching it, no one seemed interested in putting it in their mouths.
The texture was something like very cold, icy snow. As it warmed, it melted into a thick, syrupy goop that slid on hands and across the table, and that could be spooned and scooped, and poured from cup to cup.