Academic journal article Science and Children

Cabbage Chemistry

Academic journal article Science and Children

Cabbage Chemistry

Article excerpt

... adapted from ANALYSIS #10 by TOPS Learning Systems

1. Boil red cabbage leaves in a little water, and save the blue water in a labeled dropper bottle.

2. Place 5-drop puddles of cabbage water on waxed paper; set on white paper. Mix a small pinch of a different powder sample into each puddle.

[ILLUSTRATION OMITTED]

3. How does your cabbage-water indicator change color in the presence of an acid, base, or neutral solution?

4. Test whether these substances are acid, neutral, or base: baking soda, alum, vinegar, garden lime, sugar, lemon juice, corn starch, ammonia.

[c] 2009 by TOPS Learning Systems. Photocopies permitted if this notice appears. All rights reserved.

OBJECTIVE

To investigate the properties of cabbage water as an acid-base indicator.

LAB NOTES

Steps 3-4. Some degree of color blindness challenges some boys, so be sure each lab group includes at least one "color expert."

ANSWER

3. The cabbage water color is:

Pink-purple in the presence of an acid.

Green-yellow in the presence of a base.

Blue in the presence of a neutral solution.

4. Bases: baking soda, garden lime, ammonia

Neutral Solutions: sugar, corn starch

Acids: alum, vinegar, lemon juice

Bonus: Neutral to acidic beet juice remains red, but turns darker red-to-purple when basic. …

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