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🧪 ChemistryMedium

Magnetic pH Indicator with Red Cabbage Challenge

10 minutes 5 materials Ages 8-12

⚠️ Safety Warning

Adult supervision needed for boiling water. Some household chemicals should not be mixed together — test them in separate cups only.

All experiments require adult supervision.

Materials You'll Need

Gather these 5 items before starting

💡 Make sure this item is clean and ready before starting.
💡 Use room temperature water unless specified otherwise.
💡 Make sure this item is clean and ready before starting.
💡 A clear cup or glass helps you see what's happening.
💡 Use room temperature water unless specified otherwise.

💡 Tip: Check off items as you gather them to stay organized!

Step-by-Step Instructions

Follow these 8 steps carefully

1

chop the red cabbage into small pieces.

2

Have an adult pour boiling water over the cabbage in a bowl and let it steep for 15 minutes.

💧Tip: Pour slowly to avoid spills. Keep a towel nearby just in case.
3

Strain out the cabbage pieces — the purple liquid is your pH indicator!

4

Pour equal amounts of cabbage juice into 5-6 clear cups.

🫗Tip: Pour slowly and steadily. Use a funnel if you have one!
5

Add a different test liquid to each cup — lemon juice, vinegar, baking soda water, soap, milk.

🧪Info: This is where the science happens! Pay close attention to what occurs.
6

Watch each cup change to a different color!

🔍Tip: Write down or draw what you see. Scientists always record their observations!
7

Arrange the cups from most acidic (pink/red) to most basic (green/yellow).

⭐Info: You're doing great! Keep following the steps carefully.
8

Try testing other household liquids and predict if they are acids or bases.

🧪Info: This is where the science happens! Pay close attention to what occurs.

✅ Remember: Take your time with each step and ask an adult for help if needed!

The Science Behind It 🔬

Red cabbage contains anthocyanins — natural pigments that change color depending on the pH (acidity or basicity) of a solution. In acidic solutions (like vinegar, pH 2-3), the indicator turns pink or red. In neutral solutions (like water, pH 7), it stays purple. In basic solutions (like soap, pH 9-10), it turns green, blue, or even yellow. Scientists use pH indicators all the time to test chemical solutions. The pH scale goes from 0 (very acidic) to 14 (very basic), with 7 being neutral! Try changing one variable at a time to see how it affects the results — this is called the scientific method!

Grade Levels

3rd Grade4th Grade5th Grade6th Grade

Materials

Red cabbageBoiling waterStrainerClear cupsVarious liquids (lemon juice, soap, vinegar, baking soda water, milk)