Everything is brighter with rainbows even a rainy day because that’s the perfect time to hope to see one! Whether you are looking for a pot of gold at the end or love the way the colors combine, exploring rainbows through science and STEM activities is a great way to get started! Find a fun selection of simple to set up rainbow science experiments to try out all year long. Any time of the year is perfect for exploring rainbows!

Rainbow science experiments and activities for kids STEM. Rainbow science activities include making slime, growing crystals, building rainbows, and erupting rainbows!Pin

Explore Rainbows

Over the past year, we have explored rainbow and rainbow-themed science experiments. The difference? We have studied how real rainbows form and how light science plays a role in creating rainbows.

However, young kids also just love fun, rainbow-themed science activities that also showcase simple science concepts such as reactions, polymers, liquid density and crystal growing.

Below, we have included both kinds of rainbow science experiments. But before you get into all the fun, read on to learn some rainbow science.

How Rainbows Are Formed

A rainbow is formed when light passes through water droplets in the atmosphere. The water droplets break white sunlight into the seven visible spectrum colors. You can only see a rainbow when the sun is behind you and the rain in front of you.

There are 7 colors in the rainbow: violet, indigo, blue, green, yellow, orange, and red.

Make sure to look out for a rainbow next time it rains! Now, let’s try a rainbow science experiment or two!

Free Printable Rainbow Activities Guide and STEM Cards

Download this free mini Rainbow pack to get started today!

Rainbow Science Experiments

Want to turn a rainbow science experiment into a rainbow science project? Check out our easy science fair project ideas!

1.  Make A Rainbow

Grab some prisms, old CDs and more, and explore how visible light can split into the colors of the rainbow.


2. Rainbow Crystals

Grow crystals using a classic crystal growing recipe with borax and pipe cleaners. This rainbow science activity really grows awesome crystals that are both sturdy and beautiful to look at. Create a science craft with a pipe cleaner rainbow design!


3. Erupting Rainbow Science Experiment

A classic reaction for simple chemistry and a mix of colors to create an erupting rainbow!


4. Walking Water Rainbow

This walking water experiment is incredibly easy and fun to set up for kids. Watch the water travel as it makes a rainbow of color, and learn about capillary action too!


5. Build LEGO Rainbows

Explore symmetry and design with a rainbow LEGO building challenge.


6. Rainbow Density Experiment

Super easy kitchen science using sugar, water, and food coloring. Explore the density of liquids to create a rainbow.


7. Make Rainbow Slime

Learn how to make the easiest slime ever and create a rainbow of colors!


8. Rainbow Fizzing Pots

A leprechaun’s dream with a cool chemical reaction in mini black cauldrons!


10. Rainbow Oobleck

Oobleck is an awesome science activity for exploring non-Newtonian fluids. Do you know what a non-Newtonian fluid is or how it works? Learn more through this hands-on activity that uses basic kitchen ingredients.


11. Rainbow Solubility

Make this fun rainbow craft with a few simple materials and explore solubility in the process.


12. Make a Spectroscope

A spectroscope or a spectrograph is a scientific instrument used to study the properties of light. It breaks light down into different wavelengths, called a spectrum. It works similar to how a prism splits white light into a rainbow.


More Fun Science Topics To Explore

Helpful Science Resources To Get You Started

Here are a few resources that will help you introduce science more effectively to your kiddos or students and feel confident yourself when presenting materials. You’ll find helpful free printables throughout.

Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

  • 90+ classic science activities with journal pages, supply lists, set up and process, and science information. NEW! Activity-specific observation pages!
  • Best science practices posters and our original science method process folders for extra alternatives!
  • Be a Collector activities pack introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
  • Know the Words Science vocabulary pack includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
  • My science journal writing prompts explore what it means to be a scientist!!
  • Bonus STEAM Project Pack: Art meets science with doable projects!
  • Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics


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  3. I love using your projects with my grandson. I am now faced with distance learning for my students. I am a STEM teacher at an elementary school. A lot of your project lend themselves easily to distance learning. What is your position on using some of your projects in my Google Classroom? Please advise. Thank you.

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