Siena got a preschool workbook from us for Christmas and I have really enjoyed working on a few pages out of it every day with her. The other day we talked about primary colors and the mixing of colors. She loved mixing the food coloring in water and seeing the colors change.
As a side note, I had Brighton in the bouncer and Siena put a "blanket" (our dish towel..) on him. She loves mothering him. It's fun to watch.