We love painting with corks because they make such fun polka dots and are perfect size for little hands. This was a fun exploration of rainbow colors and can be made to have a strict focus on order or you can have a more open ended view. Choose what works for your child. The goal for me was to talk about the colors and let her create. If you are looking for a way to teach the color order of a rainbow try this game we shared a few weeks ago.
Paint.My daughter grabbed the corks in order but painted them starting in the inner arc. Depending on your goal for this activity you could direct your child or students to start on the outer arc and make sure to stay within the correct order. This was not my goal. At three I want her to explore and play with the colors but most of all I want her to enjoy creating her own art.