Teaching Acids & Bases: Red Cabbage Magic Color Changing Experiment
Teaching kids about chemistry can be problematic; the concepts are a bit over their heads. Talking about the PH scale or how ions react will get a blank stare, instead show them how it works with a visual project. By having fun activities, like making a color changing cabbage liquid, you’ll build their curiosity and create an experiment they won’t soon forget.
Kids Science Experiment for Teaching Acids and Bases
This whole experiment, found in the book Naked Eggs and Flying Potatoes by Steve Spangler, costs nothing more than the $2.75 for the red cabbage at the grocery store! Add a few ‘chemical reagents’ found right in your own kitchen pantry and you’ll be all set.
- Place 4-5 red cabbage leaves in a blender.
- Fill the blender half full with water.
- Puree the mixer.
- Filter the purple liquid through a strainer.
You’ll be left with 2-3 cups of a dark purple-y colored liquid. (And a kitchen that smells a little bit like cooked broccoli mixed with sauerkraut. Yum!) Line up several clear cups or glasses and start testing out all the everyday materials you can think of.
Tips for Teaching Your Kids to Make Predictions
Help your kids to make predications by doing the following:
- Ask lots of questions.
- Document your findings. Grab a paper and pencil and make a graph of your findings and see if those findings help you predict what the next item will do.
We started with vinegar, baking soda, dish soap and lemon juice. Each of these items are clearly acidic (turn the cabbage juice a bright neon pink) or clearly basic (turn the cabbage juice a dark bluish-green). We talked about similarities with the acids. Lemons are sour, right? So what else might be an acid that is also sour?
My little boy immediately suggested limes and oranges. So we tried out orange juice. It changes from a bright yellow to a pinkish-orange color. Well that wasn’t what he expected? Why did it do that he wondered? We talked about it for a while. Probably the color of the orange juice combined with the pink of the now changed cabbage juice mixed together to make the pinkish-orange!
Next we tested milk. We asked first about what we knew from our first experiments. Does milk taste sour? Does it taste bitter like the baking soda? (No. It just tastes like milk, he says). Hmmm so what will it do?
When we mixed half and half cabbage juice with milk it turned a beautiful creamy violet color. Is it an acid or a base? It’s neither! The chemical term is neutral. The PH of an acid is low(pink) and the PH of a base is high(blue), but a neutral is in the middle of the PH range. So no change in the cabbage juice color equals not a base or an acid. And the whiteness of the milk diluted the color of the juice.
The last thing we tried was macaroni and cheese. Why not!? Kids eat enough of the stuff, seems like the perfect thing to test out. We took a spoonful of the cheesy noodles and mashed them up with a fork, then added a couple tablespoons of water to the mush. Next we strained the water and mixed it with our homemade cabbage juice. What do you think? Doesn’t it look yummy!
Build-It-Yourself Chemistry Set
Making your own chemistry set can be as simple as using foods you have on hand like these:
- Potatoes
- Marshmallows
- Grapefruit
- Vitamin C Pills
- Toothpaste
- Ranch Dressing
- Mom’s Expensive Shampoo
What kinds of wacky ‘chemicals’ do your kids want to test?
The MomItForward teaching science series is brought to you by SteveSpanglerScience.com, more great ideas for teaching your kids science!
In a former life, Carissa Rogers was a molecular biologist. In her current life, she is the chief researcher of bloggy karma, parenting dos (and some don’ts), new recipes, and for spice she pretends to be a photographer. She started blogging in February of 2008 and publishes her good & crazy thoughts on GoodNCrazy.com. Find her on Twitter and Facebook.
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