Let’s Test Acids and Bases


Acids and bases are two big divisions of chemicals. Acids taste sour and they will react with some metals to give off hydrogen gas. (Don't try this yourself! Hydrogen gas is flammable!) Bases taste bitter and feel slippery. Many substances around your house are acids and bases. Let's make an indicator to show you which are which.

You will need:

  • a purple cabbage
  • water
  • pan
  • jars with lids
  • strainer or filter paper

Tear the cabbage leaves into small pieces and put them in the pan. Cover the leaves with water and cook slowly until the cabbage leaves have lost most of their color. (Ask for help with the stove, if you need it.) Let the water cool completely and then pick out the cabbage leaves. The water will be blue now from the dye in the cabbage leaves, and this is your indicator.

Pass the water through a strainer or filter to remove the last bits of cabbage. Put the indicator in jars with lids and be sure to store it in your refrigerator. Now you are ready to test for acids and bases.

You will need:

  • vinegar
  • baking soda
  • lemonade or orange juice
  • ammonia
  • bleach
  • small jars or glasses
  • spoons or eyedroper
  • paper or notebook and pencil (take notes)

BE VERY CAREFUL WITH ALL THESE SOLUTIONS! DO NOT MIX ANY OF THEM EXCEPT AS THE DIRECTIONS TELL YOU!

Put about two droppersful or a spoonful of vinegar in a jar. Add about 1/2 cup of water. Now, add a dropper of your indicator solution. What happens?

Try the same experiment with lemonade or orange juice, ammonia and bleach. Also, dissolve about 1/2 teaspoon of baking soda in 1/2 cup of water and test it. What results did you get?

Did you see a color-change during your experiments? Which solutions turned red? Which ones turned blue?

You will find that the solutions of vinegar and lemonade or orange juice are acidic. The bleach, ammonia and soda solutions are basic. Now that you know how your indicator reacts you can test other things. Some things, such as water, will not show a change. The color of the indicator will stay the same, maybe just a little lighter. That solution is a neutral one: neither acidic or basic.

http://www.halcyon.com/sciclub/

http://ofcn.org/cyber.serv/academy/ace/

http://tqd.advanced.org/2690/exper/exper...

The copyright of the article Let’s Test Acids and Bases in Kids' Chemistry is owned by Roberta Baxter. Permission to republish Let’s Test Acids and Bases in print or online must be granted by the author in writing.

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