Watching the vinegar and baking soda mix.
Each of the girls picked an individual color to make, then with the leftover mix I made a few other colors.
The paint we mixed in the small tupperware containers and left uncovered became very dry. It was difficult to use and the children were sort of frustrated with it. The colors we mixed and kept covered in the egg carton remained somewhat runny after 2 days. The colors were bright and vibrant.