Red Cabbage pH Meter
Safety Warning
Be careful in handling corrosive substances and irritants. Wear goggles and gloves at all times. Ask help in boiling red cabbage
Materials
• Red cabbage
• Water
• Boiling setup
• Acids (muriatic acid, vinegar, citrus fruits like calamansi or lemon)
• Bases (Liquid sosa, sodium carbonate, baking soda)
• Containers
Instructions
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Mix 1 cup water to 2 cups chopped up red cabbage.
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Boil the mixture for 10-15 minutes, until the leaves have lost some of their color and the liquid is a deep purple.
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Strain out the liquid.
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Pour the different acids and bases into separate containers.
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Add and pour about the same amount of the Red Cabbage indicator into the container with the acid or base.
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Watch what happens to the color of each solution.
What's the Science?
In red cabbage is a compound that changes color depending on the charge of its solvent. Acids introduce positive charges to a solution and bases introduce negative charges to a solution. The strength of an acid or a base depends on the amount of charge introduced. This allows differentiation between acids and bases of different strengths based on the color of the solution.