I think every art teacher does this project in some form, but I chose oil pastels and tempera paints for this year. We'd talked about color relationships, and students were given 5 required color schemes that had to be used in their paintings. The 6th square was a free choice square. Any color combo was allowed.
3rd grade colors: Primary, Secondary, Warm, Cool, Complementary (choose one pair), Choice
4th and 5th grade colors: Warm, Cool, Complementary (choose one pair), Analogous, Monochromatic (one color plus white or black)
I did this in four classes:
1. Color Theory Introduction: Students completed a tertiary color wheel using red, yellow, and blue colored pencils. (3rd graders just did primary and secondary colors.)
2. Color Relationships/Introduction to Kandinsky: Warm, Cool, Analogous, Monochromatic, Complementary
3. Pastel Drawings: We folded a 9x12 piece of manila drawing paper into 6 squares (fold once vertically, then fold into thirds). I walked through each color scheme with students as they applied pastels in circles of varying thickness, beginning with a dot. I encouraged students to apply the pastel heavily. I also had to keep reminding them to make some of their circles thick, otherwise I would have ended up with a bunch of skinny concentric circles and A LOT of "naked" paper.
4. Paint with Tempera: Because I'm mobile, I use tempera disks. (I bought the set with lids from School Specialty.) I'm not crazy about how chalky these feel after they dry, but they do serve their purpose well, and the colors are intense.