Rainbow Mentos & Soda Geyser Experiment for Kids
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Looking for an exciting outdoor STEM activity that kids will never forget? This Rainbow Mentos and Soda Geyser experiment is a colorful twist on the classic exploding soda science experiment!
Kids love watching the soda shoot high into the air in bright rainbow colors, and parents love that it combines chemistry, physics, and hands-on learning in one unforgettable activity.
This experiment is perfect for:
- summer science fun
- backyard STEM play
- homeschool science
- science camp
- group activities
- outdoor parties
Why Kids Love the Mentos and Soda Experiment
This activity is:
- fast-paced and exciting
- colorful and visually dramatic
- easy to set up
- great for groups
- packed with real science concepts
The giant soda eruption feels almost magical the first time kids see it!
Supplies Needed
- 2-liter bottles of soda
(Diet Coke works best for height, but colorful sodas make an amazing rainbow effect!) - Rolls of mint Mentos
- Paper
- Outdoor space
Optional:
- Different soda flavors/colors
- Measuring tape
- Safety goggles
How to Make a Rainbow Soda Geyser
Step 1: Set Up Outside
This experiment gets VERY messy, so make sure to do it outdoors in an open area.
Step 2: Arrange Your Soda Bottles
We used colorful sodas to create a rainbow effect:
- orange soda
- grape soda
- lemon-lime soda
- blue and green sodas
- Diet Coke
Diet Coke typically creates the tallest geyser, but colorful sodas make the experiment even more fun visually!
Step 3: Prepare the Mentos
Roll several Mentos candies tightly inside a half sheet of paper so they can slide easily into the soda bottle all at once.
Getting all the Mentos into the bottle at the same time is important for the biggest eruption.
Step 4: Launch the Geyser
Quickly drop the Mentos into the bottle and step back immediately.
Within seconds, the soda will erupt into a giant fizzy geyser shooting into the air!
(Be prepared for lots of laughter and excitement — this activity is always a huge hit with kids.)
The Science Behind the Mentos and Soda Reaction
This experiment demonstrates gas release, pressure, and nucleation.
Soda contains dissolved carbon dioxide gas (COâ‚‚). The surface of Mentos candies is covered with thousands of tiny microscopic pits and rough spots that act as nucleation sites.
When the Mentos are dropped into the soda, carbon dioxide bubbles rapidly form all over the surface of the candies. This sudden release of gas creates intense pressure inside the bottle, forcing the soda upward in a dramatic eruption.
The shape of the bottle helps direct the pressure upward, creating the famous soda geyser effect.
This activity is a fun way for kids to explore:
- chemical reactions
- gas pressure
- states of matter
- force and motion
- cause and effect
Which Soda Works Best?
One of the most fun parts of this activity is experimenting with different sodas.
We noticed:
- Diet Coke usually erupts the highest
- Mountain Dew tends to be less dramatic
- Colorful sodas create the best rainbow effect
Kids can turn this into a real STEM investigation by testing:
- different soda brands
- diet vs. regular soda
- warm vs. cold soda
- different amounts of Mentos
Ask kids:
- Which soda created the tallest geyser?
- Why do some sodas react differently?
- Does temperature affect the eruption?
Turn It Into a STEM Investigation
Want to make this activity even more educational?
Download my free printable STEM Lab Sheet to help kids:
- make predictions
- test variables
- record results
- compare soda reactions
- think like scientists
It’s an easy way to turn a fun outdoor activity into a real hands-on science lesson.
Safety Tips
- Always perform this experiment outdoors
- Stand back immediately after dropping the Mentos
- Avoid aiming bottles toward people
- Wear old clothes or safety goggles if desired
Summer Science Camp
This activity is also included in my Summer Science Camp book — a collection of hands-on STEM projects, outdoor science activities, and printable learning pages designed to make summer learning fun and easy.
Perfect for:
- homeschool families
- summer enrichment
- camps
- classrooms
- bored kids on hot afternoons
If your kids love exciting science experiments, be sure to check it out!
More Exploding STEM Activities for Kids
If your kids loved this activity, try these other exciting science experiments:
- Easy Bottle Rockets
- Film Canister Rockets
- Elephant Toothpaste
- Lemon Volcano Experiment
- Baking Soda and Vinegar Balloon Experiment
If your kids love hands-on STEM activities like this, they may also enjoy my book Science Art and Drawing Games for Kids, filled with creative ways to combine science, art, and learning through play. It’s packed with engaging activities designed to inspire curiosity, creativity, and critical thinking.
These all look so fun!!! Thanks so much for including our dancing raisins!
This is a great collection! Thanks for including our Fizzing Dinosaur Eggs–I’m pinning!
So much fun for hands-on learners!
Have you seen the Mentos fizzy YouTube videos? Hilarious. They set them off to music or stage them to go off in a series. Awesome.
My boys are going to love these!
We recently went to a Mad Science class which has me thinking about explosive science again. I am going to have to try the mentos thing.
Thank you for sharing this! I love all the ideas. Hope you have a great idea you can share again today when you have the time!
http://littlebinsforlittlehands.com/ultimate-sensory-play-party-linky-2/
Can’t wait to try this!