This looks like the all time coolest craft/science activity/gift! Make your own colorful rainbow paper with just three materials! Easy physics demonstration, art project, and science activity for kids of all ages. The Science Kiddo
Rainbow activities: Rainbow Sponge Painting - a fun art for kids that explores color mixing and blending. It's a bit of a twist on traditional sponge painting and there are lots of ideas for developing learning opportunities too.
This ultimate collection of rainbow activities includes over 40 ideas that will strengthen toddler color recognition skills. Included is art, sensory, and cooking activities for the classroom and homeschool!