I had no idea how big of a container of baking soda they used, so I just kind of made up my amounts. I probably used around 1 1/2 C of baking soda, 1/2 C of cornstarch, and 3/4 C hot water. I divided it into 3 parts and mixed in red, blue, and yellow food coloring. Now if you let it sit it separates a bit, and when you mix it, it reminds you of oobleck. Maybe I should have used more water, but it would have been so thin.
Then I turned the kids loose with paintbrushes. Even Eli thought it was great fun to paint.
Then I introduced a spray bottle filled with vinegar, and the fun began! They would paint and spray and paint and spray.
Then Eli accidentally knocked over the cup of blue paint. Bria started spraying it, and they realized how much more of a mess they could really make. So all the colors got dumped and sprayed. And the clumps in the bottom of the cup (which basically were colored oobleck) got dug out and sprayed.
They sprayed and splashed and sprayed some more until they were out of vinegar.
Then Bria wanted to see what affect water would have. She filled the bottle and splashed it on. She looked down, and says, "It made a hole!" So there was more splashing, and most of the paint was washed away!
Well at least from the sidewalk.