All of my kiddos (ages 4-11) loved this colorful (& smelly) science activity! Red cabbage contains a chemical called an indicator, which changes color when it comes into contact with other things that are acidic or alkaline. We used a variety of household liquids and the kids had fun coming up with even more things to test.
First, I finely sliced 1/2 of a small red cabbage and added it to a mixing bowl.
Next, I heated up 2 cups of water in the microwave until almost boiling (approx. 2 minutes) and poured it over the sliced cabbage.
We let it sit for 15 minutes, then the kids took turns bashing the cabbage with a wooden mixing spoon (because it helped release more of the color and it was fun!).
Then we strained the cabbage through a small colander, catching the purple juice in a large measuring cup.
The kids labeled 1 ounce plastic medicine cups (you can get a pack of 100 on Amazon for under $4 – we use these for so many things) so we could refer back to what we added in each (i.e. L for lemon, B for baking soda, etc). Add the same amount of cabbage juice (we did 5 ml) to each measuring cup, then begin added your various household liquids – we used plain water, lemon juice, baking soda, milk, vinegar, hand soap, peroxide… I even added baker’s ammonia (Ammonium Carbonate) to one, which by the way is a very cool baking ingredient to check out if you aren’t familiar with it). My oldest had the idea to combine some of the liquids to try to create different strengths of the acidic and alkaline liquids which produced some even more unique colors.