Try This: Red Cabbage Indicator

There are plenty of fancy ways to test to see if something is an acid or a base, but you can also do it simply in the comfort of your own home.

QUESTION

How can you figure out if something is an acid or a base?

MATERIALS

Cabbage indicator — the liquid from a jar of pickled red cabbage, available at the grocery store

Eyedropper

1 small plate for each of the materials you wish to test. Below are some samples:

Lemon juice

Orange juice

Baking soda

Vinegar

Antacid tablet

Tea bag — mix with water to make tea

Ground coffee

indicator: a liquid (like the juice of a red cabbage) that tells you if something is an acid or a base.

PROCEDURE

  • Pour some of the indicator into several small plates.

  • Drop a small amount of each test item onto a plate and watch what happens to the indicator.

WHAT'S HAPPENING

With some of the test samples, the indicator will turn a pink color. That is your clue that you've tested an acid. Other samples should have turned the indicator greenish blue. Those are the bases. Now that you know what to look for, can you find other acids and bases in your kitchen?

CAUTION: Some acids are very dangerous to humans. Be careful not to get any of the samples on your skin, and never try to eat or drink things that you are experimenting with.

Cool Quotes

The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka!” (I found it), but “That's funny.…”

— Isaac Asimov, author and biochemist

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