What happens when you mix cranberry juice and baking soda? Way more than you’d expect. This simple science project turns a kitchen staple into a color-changing chemistry lesson.
Kids compare three jars to see how acids and bases react, and why cranberry juice changes color.
How to Do the Fizzing Cranberry Experiment
Crawling Colors Science Experiment
Get the printable100% cranberry juice
White vinegar
Baking soda
Three clear jars or cups
Spoons and droppers
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Set up three jars
Fill jar 1 halfway with vinegar, and jars 2 and 3 halfway with cranberry juice. Jar 2 is your control.
Predict
Ask kids what they think will happen when you add baking soda.
Vinegar jar
Add 1 teaspoon baking soda to jar 1. It fizzes, but the liquid stays clear.
Cranberry jar
Add 1 teaspoon baking soda to jar 3. It fizzes, and the red starts shifting toward purple.
Compare
Hold jar 3 next to jar 2. Which had more bubbles? Which changed color?
Keep experimenting
Add more baking soda to jar 3 a little at a time and watch the color keep changing.
Good to know
This is fizzy and messy in the best way, so keep everything on a tray. Nothing here is for drinking once it’s mixed.
Why Cranberry Juice Changes Color
Vinegar and cranberry juice are both acids. Baking soda is a base. When acids and bases meet, they make carbon dioxide gas, which is the fizz.
Cranberry juice also has natural pigments called anthocyanins that act like a pH indicator. As baking soda makes the juice less acidic, the color shifts from red toward purple.
Love this? Write secret messages with cranberry spy ink.
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Love fizzy science? Try our lemon volcano experiment.
The science experiment includes
- Step-by-step directions
- Prediction and observation sheets
- Simple science explanation
- Instant PDF download, nothing is shipped
Perfect for
- Science centers
- Homeschool
- Holiday science
- Ages 4 and up
Cranberry Science FAQ
It fizzes and turns from red toward purple.
Cranberry juice is acidic. Acid plus baking soda makes carbon dioxide bubbles.
Cranberry pigments change color as the juice becomes less acidic.
It shows what the juice looks like with nothing added, so kids can compare.
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We love seeing these activities out in the wild: the lumpy letters, the snack breaks, the proud “I made a B!” moments. Leave a star rating, tell other parents what worked (and what totally didn’t), and add a photo of your setup if you’d like.
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