The plan had been to make our own Oobleck the next day, but I pushed it off for a couple of days to get Zoo Boy used to the idea and OK with me and J doing it. He wasn't involved when we did it, but at least he wasn't insisting that we NOT make it by the time we did. This Oobleck is just corn starch, water, and a little green food coloring.
J was totally into the project -- literally. The corn starch is so fine and well-suspended in the water that it acts like a liquid, until you apply pressure to it, at which point it forms a solid that you can actually mold with a bit, although the minute you release the pressure, it "melts" back into a liquid again very rapidly. It's fun stuff to play with.
J plays at lifting the Oobleck and allowing it to drizzle back into the bowl. Depending on how much pressure you apply to it as it drizzles out your finger, you can make the strings of drizzle various thicknesses and viscocities. Of course, I didn't have to point that out or use any of those sorts of terms, I just let him fiddle around with it and make his own discoveries.
Which is one way I've found to take pre-designed activities and make them more in-line with the educational philosophy we're using. I just take out the explanations and "lesson", and just present the material on it's own merit. J can connect the dots pretty well on his own -- in fact, he noted that the Oobleck behaved like both a liquid and a solid (states of matter being the topic of the class he took). That was the point of the lesson, but we were able to get there via his own experience and discovery rather than my labeling it as such for him. This type of learning produces a much deeper-seated understanding, and since the discovery process is all his, he "owns" his education.