Rainbow science experiments and rainbow STEM activities are a fun way to present STEM topics to kids in a colorful way. In this rainbow STEM activity, flip a rainbow using the science of light refraction. The light refraction science experiment takes just a few minutes, but it illustrates a really cool scientific concept in an easy-to-understand way.
We love doing simple STEM activities like this because it’s an easy way to slip in a bit of science no matter where you are!

Keep reading to learn how to flip a rainbow with science!
Light Refraction Experiment in a Jar
Flipping an arrow, rainbow, or word with physics is super simple to do, but much harder to explain!
Learn a bit about how light refraction works before starting your own version of the experiment.
If you want to try another version of light refraction, this refraction experiment with pencil version is also fun to try!

How Light Refraction Works
Light travels in waves (and sometimes particles). Because of that, when the light passes through the rounded jar, the light can bend (AKA refract).
Light travels from the air, through the glass, through the water, out the other side of the jar, and then back through the air.
Then it finally hits the paper.
Because light is bending and the sides of the jar are curved, the light bends toward the center. Where the light meets is the focal point, but on the other side, the image appears to reverse to the eye.
This happens when the light rays that have bent pass each other and the placement of the focal point changes. This makes the image flip.

This happens inside of your eye as well. Your brain has to flip the image manually to get things to look right side up!
Physics Central has a cool diagram about how the light bends and flips mid-air.
Light Refraction Experiment for Kids Lesson Plan

If you need a lesson plan for the light refraction experiment, click the link below to get the 12-page lesson pack including worksheets, lesson guide, step-by-step directions, and quizzes! And find more no prep STEM challenges here.

What you need for the light refraction in water experiment

Here’s what you need for this activity:
You’ll also find directions for this project and 29 other cool science experiments in The Mason Jar Scientist!
The Mason Jar Scientist: 30 Jarring STEAM-Based ProjectsBall Regular Mouth Mason Jars with Lids and Bands, 16-Ounces (4-Pack)
Crisco Pure Vegetable Oil, 32 Ounce
Barbasol Soothing Aloe Thick & Rich Shaving Cream 10 Oz (2 Pack)
Alka-Seltzer PFY BXAS50 80659297 Antacid and Pain Relief Medicine, Two-Pack (Pack of 50)
Kadaon 10X Handheld Magnifier Antique Mahogany Handle Magnifier Reading Magnifying Glass for Reading Book, Inspection, Coins, Insects, Rocks, Map, Crossword Puzzle
BORAX 20 Mule Team Laundry Booster, Powder, 4 Pounds
Fine Ground Celtic Sea Salt – (1) 16 Ounce Resealable Bag of Nutritious, Classic Sea Salt, Great for Cooking, Baking, Pickling, Finishing and More, Pantry-Friendly, Gluten-Free
McCormick Assorted Food Color, 1 Fl Oz (Pack of 1)
Food Coloring – 12 Color Vibrant Cake Food Coloring Set for Baking, Decorating, Fondant and Cooking – Upgraded Liquid Concentrated Icing Food Color Dye for Slime Making, DIY Crafts – .25 fl. oz. Each
30% Pure Vinegar – Home&Garden (1 Gallon)
Arm & Hammer Pure Baking Soda, 5 lb
Argo Corn Starch 16 oz. Box (Pack of 4)
How to Do the Light Refraction Experiment
One of the cool things about light refraction is that it really can look like magic!
First, you’ll want to fill a jar with water. The smoother the jar the better.

Draw a rainbow (or a word) on a piece of paper. Write big so that the experiment is more dramatic.
Place the piece of paper behind the jar.

Slowly move the piece of paper back and forth behind the jar. The image should flip halfway through and show the image in reverse!
If it doesn’t, move your position until you can see it happen. The angle can make a difference in how much of a dramatic “flip” you get.

Discuss why this happens with your kids.

More Rainbow Science Lessons!

If you love this flip a rainbow science experiment, you’ll love all the experiments in the rainbow lesson bundle!
This bundle includes 4 rainbow science lessons complete with worksheets, lesson guide, discussion topics, and quizzes!
Click the image below to get a sneak peek at what’s inside the pack!
More Light Activities
Kids will also like these light STEM activities!
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