Because I am often asked what materials I use in my sand and water table, I am writing a series of posts about those materials. I started to introduce some of those materials in posts about two of my favorite materials: sticks and rocks. I also wrote about a couple of the most elemental materials I use in the table, namely, water and sand. (By the way, water comes in different states and there are several different types of sand.) In February, I wrote a post on feed corn. In April, I wrote about wood pellets. In May, I wrote about water beads.
In this post, I would like to write about oobleck in the sensory table. Oobleck is a mixture of cornstarch and water. When mixed together, the solution of cornstarch and water has unique properties. If you squeeze it, it is like a solid. If you let it go, it melts or flows like a liquid. In scientific terminology it is called a non-Newtonian fluid that changes from a liquid to a solid state when stress is applied. In other words, it has properties of both a solid and a liquid. (3M has made a lot of money off a substance with such properties with their post-it notes and removable hooks.) I have no recipe for the ratio of cornstarch to water; I mix until I get the consistency I want. If there is too little water, the mixture is too hard. If there is too much water, it is too runny.
The first time I used oobleck in the sensory table, I set it up with a knob ramp. It was basically a wooden ramp set on an incline. Small dowels were arranged in a cascading fashion.
In fact, for some children it was hot lava. The two children in the video clip below filled their bowls with hot lava and then created a genuine "lava flow."
Pouring and Catching the Hot Lava from Thomas Bedard on Vimeo.
In the video clip below, the child discovers that when the oobleck is squeezed or pinched, it feels solid to the point that she says:"It feels like a ball is in there, a snowman."
The second time I put oobleck in the sensory table. I paired it with a platform I created out of pvc pipes and a sheet of black plastic.
The platform allowed the children to explore the oobleck without getting the gooey stuff all over their hands. The children pictured below talked about making pancakes on the griddle.
Although, if a child wanted to feel what it was like to totally immerse their hand in the oobleck, the platform was perfect for holding the measuring cup stable .
Not only did this child feel what it was like to bury their hand in the oobleck, they also conducted a science experiment about displacement. The child started with a full cup of oobleck. As they immersed their hand, the oobleck oozed over the side of the measuring cup. When the child pulled their hand out of the measuring cup, it was no longer full.
One of the biggest surprises for the children---and me---was what happened underneath the platform as the oobleck oozed through the holes that were drilled in the platform. The oobleck took the form of slow raindrops with a tail.
Was it messy? Of course it was messy, but oh so much fun and full of rich possibilities for working with a non-Newtonian fluid. Besides, it was easier to clean up than one might imagine. The children could just dip their their hands in a bucket of water and the oobleck would rinse right off. And bathing the apparatus and the table with water allowed me to just dump out the diluted solution.
One of the nice things that happened handling the oobleck was that the cornstarch in the oobleck softened our hands.
If you are interested in reading about how the children explored the oobleck and the setups, the following three links reference my original blog posts:
