I filled empty Gatorade bottles with water and then added watercolor to create "Rainbow Bottles". The kids had fun putting them in "rainbow" order.
We did the Ivory Soap experiment (you can find it HERE), and used colored water to drip the colors of the rainbow on to the experiment.
Hanging rainbows made with tissue paper strips, half a paper plate and cotton balls.
Blow art (excellent for speech development!) using "rainbow colors" I love the ways these turned out. Just be prepared for some "spittle".
Rainbows in Clouds, aka, dripping colored water onto shaving cream and watching the colors come through. You can find the experiment HERE..
Lastly, after exploring the rainbow in so many ways we created our own Rainbow Books, I got the idea from TEACH PRESCHOOL.
Enjoy the Rainbows!