Friday, January 8, 2010
Experiment 13: Red Cabbage Indicator
Here's the set-up of our experiment. We don't have any
test tubes, so we used small plastic cups. I also recommend
having a pH indicator color chart ((I got mine from page
13 at the Surfing Scientist) as the kids really were excited
to examine the chart to see whether it was an acid or a base
and to decide how strong it was compared some of the
other things we tested.
1) Assemble the chemicals you wish to test (distilled water
is pH neutral, acids include lemon juice and vinegar, bases
include laundry soap and baking soda).
2) Fill the small cup half-way with red cabbage juice
3) Place the card to be tested behind your cup of red
cabbage juice. Add the chemical to be tested. Stir with
4) Examine the pH indicator color chart and determine
whether your chemical is an acid or a base.
It's useful to test chemicals because strong acids and
strong bases react together (think of the bubble bomb
and volcano). Also, very strong acids and very strong
bases can be dangerous and must be handled with care
(of course, we didn't use any dangerous chemicals, but
scientists often do).