I mixed red cabbage juice with baking soda and vinegar — and watched the colors change from purple to blue to pink! It felt like magic, but it’s really acid-base chemistry.

The Experiment Setup

Here’s what I used:

• Red cabbage (boiled to extract the juice)
• Baking soda (a base)
• Vinegar (an acid)
• Clear cups to see the color changes

What I Learned

I learned that scientists use something called “pH indicators” to measure how acidic or basic something is. The cabbage juice contains anthocyanins, which are natural pigments that change color based on pH:

• Red/Pink = Acidic (like vinegar, lemon juice)
• Purple = Neutral (like water)
• Blue/Green = Basic (like baking soda, soap)

The Science Behind It

The pH scale goes from 0 to 14:

• 0-6: Acidic
• 7: Neutral
• 8-14: Basic (alkaline)

When I added vinegar to the cabbage juice, it turned pink because vinegar is acidic. When I added baking soda, it turned blue-green because baking soda is basic!

Next Experiment

Now I want to try it with pool water next time. I’m curious to see what color it turns and whether our pool is properly balanced. Maybe I can even test different household liquids and create a color chart!

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What’s your favorite kitchen science experiment?