Acid & Base Indicator

Chemistry Honors 4th quarter project

The Ph Scale

The Ph scale shows the acidity or the alkaline for any substance. Ranging in a scale going from (Acids)red to pink to dark pink to (neutral)purple to (bases)blue to aqua to green to yellow. The scale contains numeric values that go from acids 0-6 to bases 8-14 also 7 is the neutral so it is a balance between acidity and alkalinity.

purple spotter the indicator

when in doubt, indicate it out. (slogan)

Use our indicator to determine if something is to acidic for you

  • Use our purple spotter to test the Ph level of your city's tap water.
  • Use our purple spotter to find the Ph level of the soap before using it on the skin.
  • Use our purple spotter to find the Ph level of your favorite bottled water to see if it is healthy to drink.
  • Use our purple spotter to find the Ph level of your favorite shampoo.
  • Use our purple spotter to find the Ph and add acids or bases to make the solution more safer to be sold on the market.

This indicator is safe and easy to use, non toxic, changes color in acids and bases.

How it works

Red cabbage contains a molecule called anthocyanin which changes according to the hydrogen concentration. Very acidic is red and basic solutions are greenish yellow and neutral is purple. Acids add more hydrogen ions to the solution, while bases remove hydrogen ions of the solution. The anthocyanin indicates how much hydrogen ions are in the solution and so it changes color to the amount of hydrogen ions in the solution showing us if it's acidic or alkaline.

The experiment.

The things you'll need is:


  • 4 ounce of water
  • 8 red cabbage leaves
  • a blender
  • 20 strips of a coffee filter
  • 8 cups
  • a syringe
  • soap bar (Sodium hydroxide)
  • Liquid Castile soap (Potassium hydroxide)
  • Baking soda (Sodium Bicarbonate)
  • Antacid Tablets or chalk (Calcium Carbonate)
  • Orange juice (Citric Acid)
  • Vinegar (Acetic Acid)
  • Tea (Tannic Acid)
  • Milk (Lactic Acid)
  • a spoon
  • some toothpicks

The ingredients that need to be prepared.

Using a syringe get 2ml of water and place into cup

Place tums in a cup full of 2ml of Distilled water.

Crush the tums until thoroughly mixed.


Using the syringe get 2ml of water and a 1/2 a teaspoon of baking soda and place in a cup

thoroughly mix it until baking soda dissolved


sprinkle some water on to the soap bar and create a lather in between hands. get a cup and using the side of the cup, extract the soap lather off of your hands.

The Sci Guys: Science at Home - SE2 - EP4: Red Cabbage pH Indicator - Acid Base Indicator
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