Red Cabbage Litmus Experiment
*This post contains affiliate links.
One of the books we’re using as part of our science curriculum this year is Science in the Kitchen by Rebecca Heddle (an Usborne book). It explains wonderful, easy experiments using items you have around the house!
Last week, we talked about taste buds and did some tests with sweet and bitter foods. Today, we discussed sour things and conducted a test with red cabbage water to see which foods and beverages are acids and which are bases. (The book calls them non-acids to keep it simple for younger learners.)
First, while I boiled water, the girls tore the red cabbage into small pieces and put it into a pot. When the water was boiling, I poured it over the cabbage pieces and let it sit until it cooled off (30-40 minutes). Then, I strained out the cabbage leaves. We were left with pretty purple cabbage water to use for our experiment!
Next, I filled lots of applesauce cups that were destined for the recycle bin with the red cabbage water.
Then, we created a list of foods and drinks we wanted to test. (We didn’t buy anything special—just looked around to see what we had!) The girls made predictions about whether they contained acids or not. We decided to check lemon juice, sugar, cinnamon applesauce, apple juice, milk, grape juice, apple cider vinegar, salt, filtered water, Coke Zero, and iced tea.
The red cabbage water turned pink when acids were added and stayed purple or changed to a dark bluish-green when bases were added. Some of the foods yielded obvious results immediately. With others, the “answer” became more obvious after it had sat there for a while.
I had the girls check their predictions against the actual results on the chart we made. They were only wrong three times!
We had quite an array of colors by the time we finished.
This experiment was a lot of fun, and the only cost was time and the money I spent on red cabbage!
More kitchen chemistry resources:
– Amazing Kitchen Chemistry Projects You Can Build Yourself
– Janice VanCleave’s Chemistry for Every Kid: 101 Easy Experiments that Really Work
– Testing For Starch Experiment