This is one of Aya’s most favorite experiments, maybe because it is really fun to mix liquids and watch them turn into different colors. Nowadays, when I ask her what an “acid” is, she immediately recalls the experiment and tells me, “It’s the one that makes the red cabbage juice turn red!” 🙂 (Break muna sa mga seryosong usapan, I’m lagging behind with the experiments! This one was done many months ago actually.)

For this experiment, you’ll need the following:
1. red cabbage
Side note: Aya argued that the “red” cabbage is actually “purple.” Are we color blind or something? Kids. Sigh.
2. 2 jugs
3. sieve
4. glasses
5. hot water
6. test substances: vinegar, lemon juice, bicarbonate of soda, etc.

First, Aya tears up the red cabbage and puts it into one of the jugs.

Hot water is poured into the jug to cover the cabbage. Let it stand for about 30 minutes. (Aya: “Hahh…tagal naman!”)

Strain the cabbage juice into the other jug. Side note: I had to help Aya with this because the water was still too hot!

Next, pour the cabbage juice into the glasses.

Add a test substance to each of the glasses. Here, Aya tests the bicarbonate of soda. Vinegar has already been added to one of the glasses, which turned the cabbage juice into bright red.

Experiment is done! Dami kulay, Nanay! Aya triumphantly poses for the camera to show off her results. 🙂

Explanation: Red cabbage contains a pigment molecule called flavin (an anthocyanin) which changes colors depending on the pH of the substance added to it. This makes it a good pH indicator, turning red when acid is added (e.g., vinegar, lemon juice, etc.) or dark blue when alkalis are added (e.g., bicarbonate of soda, antacid, etc.).

Kids and parents, try this at home! 🙂