What explains the result?
Pigments in cabbage change structure with acidity, producing a different visible color range.
PHYSICAL SCIENCE · GRADES 5–10
Red cabbage pH color lab
INVESTIGATION QUESTIONHow does acidity shift indicator color?
● ILLUSTRATIVE SCIENCE MODEL
ENGLISH CAPTIONS
Prepare the cabbage indicator. A common starting solution makes color comparisons more meaningful.
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Where does this matter?
Indicators help scientists test water, soil, and chemical solutions.
What should you keep in mind?
Color bands are approximate; concentration, lighting, and cabbage preparation affect the shade.
DEDICATED NATURAL INDICATOR LAB · GRADES 5–10
Cabbage
color lab
Extract a plant pigment, dispense it into separate sample wells, and use each color shift to compare acids, near-neutral liquids and mild bases.
EXTRACTION → MICROWELL TEST RACKSTEP 1/6 · CHOP CABBAGE
PURPLE CABBAGE
ACIDBASE
The same indicator changes hue as its pigment responds to the sample environment.
READ THE EVIDENCE
From pigment to pH clue
Red cabbage contains water-soluble anthocyanin pigments. Their molecular structure changes with acidity, changing which wavelengths they absorb and the color we see. Very acidic samples tend red; near-neutral samples often look purple; mild bases shift blue or green.
Try it in real life: compare lemon juice, water and baking-soda solution using equal indicator amounts in separate cups. Use an adult for the hot-water extraction, let it cool, label every cup, wear eye protection, and never mix cleaning products or taste test solutions. Household indicator colors estimate broad ranges; use calibrated pH paper or a meter for precise readings.