I got this idea from Art is the Best Part of the Day, but I wanted to use it to introduce tints and shades to 2nd grade. We first made the circles by stamping a styrofoam cup in black tempera. Then I let them pick one color. We painted with the one color for about 10 minutes, then I went around and added a little bit of white to each students' paint. We did this for the rest of the period, adding more and more white. The next class we did the same but added black for the shades. The kids loved it! We also talked a little about printmaking, covered shapes, repetition and overlapping. I told them to use their fat brushes for the large areas, and their skinny brushes for the small areas. They got a kick out of this. Also, the boys who picked red where a little upset when they got pink after adding white. They wanted to switch colors but I wouldn't let them. What a meanie!