======Red Cabbage Rainbow pH Indicator======


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**Alternative titles:** Natural pH Indicator with Cabbage
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====Summary====                   
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====Procedure====  
  - Chop red cabbage and boil it in water until the liquid turns deep purple.  
  - Strain and cool the liquid to collect the cabbage extract, which serves as the indicator solution.  
  - Prepare a series of test tubes with water.  
  - Add small amounts of acidic and basic solutions to adjust the pH across a range of values.  
  - Place a few drops of cabbage indicator into each test tube and observe the resulting color changes.  
  - Compare colors to approximate pH values, creating a visual rainbow of acidity and alkalinity.  
  - Test common household substances such as vinegar, lemon juice, baking soda solution, dish soap, antacid solution, and bleach by adding the indicator and recording the color change.



====Links==== 
Red Cabbage Rainbows - Royal Society of Chemistry: 
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pH Rainbow Tube - Kitchen Chemistry Experiment - Anne Helmenstine: 
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📄 Students Turn Kitchen Science into a Red Cabbage Rainbow - MICDS: [[https://www.micds.org/news/article/students-turn-kitchen-science-into-a-red-cabbage-rainbow/]]\\


====Variations====
  * Try other natural indicators like beet juice, turmeric, or blueberry extract.  
  * Use cabbage indicator on pH paper to compare precision with liquid testing.  
  * Test beverages (soda, coffee, tea) for acidity levels.  
  * Create a full-scale pH color chart by matching indicator colors to known pH solutions.



====Safety Precautions====
  * Use caution when boiling cabbage; handle hot liquids carefully.  
  * Wear goggles and gloves when testing strong acids or bases like bleach.  
  * Dispose of chemicals safely and according to school or lab guidelines.  
  * Clean up spills promptly to avoid staining from the cabbage solution.




====Questions to Consider====
  * Why does red cabbage change color with different pH levels? (The anthocyanin pigment changes molecular structure in response to hydrogen ion concentration.)  
  * What color does cabbage juice show at neutral pH? (It appears bluish-purple around pH 7.)  
  * Why do different household substances show different colors with the indicator? (They contain varying levels of acidity or alkalinity, altering the pH.)  
  * How does this compare to a commercial pH test strip? (Cabbage gives a broad color range but is less precise than standardized pH paper.)