Cool. That’s all I can say. Purple cabbage has a pigment that changes color when a base or acid is mixed with it. Bases and acids are opposites on the ph scale going from 0 (base) 14 (acid) Bases are milk soap, soda. Acids are lemon juice and vinegar. Water is neutral at ph7. The magic cabbage juice changes color when you add a base or an acid. You can get a wide range of colors as you add liquids of all different ph’s.
I think most people will have everything on hand except for a head of purple/red cabbage. Ask your mom to put it on her grocery list. It will keep you busy for a long time on a cold winter day. We actually did this several times and there is another cool thing we did the next day. Here is part two where I make magic pH paper out of the same cabbage juice. Link
Here’s what you need for this first experiment:
3-4 cabbage leaves peeled off or cut a 1/4 of the cabbage off in a wedge
Blender full of water (6-8 cups) you want a ratio of 1 leaf to 2 cups water
A sieve or fine mesh colander
Clear glass cups, bottles or bowls
Different household liquids of different ph ( some acidic/some base)
I used lemon juice, vinegar, milk, laundry soap, dish soap, baking soda, alka seltzer, pop
Blend the cabbage and pour juice out into a mesh strainer over a bowl.
Next fill glass cups full of juice. I had 8 cups and 8 different items to mix in. Start adding your liquids one at a time and stir. You only need to add a tablespoon to get a reaction. This is the best part. We lined up the different colors according to the ph scale with red being acid, green being a base and pink and blue shades in between.
There are lots of things to experiment with around your house. We stored extra cabbage juice in a glass jar sealed uo in our fridge for a few days and it worked later on just great.
This idea could be used for a school science fair project.
Laundry soap was my favorite because it made green. This picture shows green the best.