One of the things I anticipate most about the spring season is dying eggs with my family. It’s one of those things that is always fun no matter how old I get.
This year we added another interesting dimension to our egg-dying party by using a beautiful all-natural red cabbage egg dye. The red cabbage turned our eggs a deep blue and prompted us to do further red cabbage indicator science experiments in the kitchen.
We learned about acid/base chemistry by using various kitchen materials to paint our dyed eggs. For those of you who love science AND love doing things naturally (even organically!), this is the perfect activity for you.
Hard Boil Eggs
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I headed to the kitchen to get ready to make our red cabbage dyed eggs.
Before inviting the kids to join me I hard boiled about a dozen eggs. My favorite method for hard boiling eggs these days is to use my Instant Pot! It produces eggs that peel so easily sometimes the entire shell comes off in one piece!
To hard boil eggs in the Instant Pot simply place the eggs on the rack that comes with the appliance. Pour 1 cup of water into the bottom, select Manual Mode, and set the Pot to pressure cook for 5 minutes. Once it is done, release the pressure and place the eggs in an ice bath so that they stop cooking immediately.
If you don’t have an Instant Pot, just hard boil eggs as you normally do.
Prepare a Natural Egg Dye with Red Cabbage
While the eggs were cooking I prepared the red cabbage dye. I gathered the following supplies:
- One half of a head of red cabbage
- Knife and cutting board
I chopped up the red cabbage into coarse pieces and threw them into the saucepan. I added just enough water to cover the red cabbage pieces and then set the saucepan on the stove to boil.
Once the red cabbage dye began to boil I turned off the heat, covered the saucepan, and let the mixture cool down naturally.
When the eggs and red cabbage juice were cooled down, I placed them in a large bowl together. The idea is to cover all the eggs completely with red cabbage juice so that they get dyed a natural deep blue!
I placed the bowl of red cabbage and eggs into the refrigerator and left it overnight.
The next morning, I pulled the eggs out, rinsed them off, and let them dry completely. They were the most gorgeous shade of blue!
Red Cabbage Egg Dye Experiment
Finally, I invited the kids over to complete our red cabbage egg dye experiment. I gathered these supplies:
- Baking soda
- Q-tips or paint brushes to paint the eggs
I poured some vinegar into a small cup. Vinegar is a weak acid that will change the color of the red cabbage indicator to pink.
In another cup I mixed 1/2 tsp baking soda with enough water to dissolve it. Baking soda acts as a base and turns red cabbage juice greenish-blue.
The kids used Q-tips to paint designs onto the eggs. They were so surprised to watch the surface of the eggs change from blue to pink when they pained with lemon juice!
The egg shells turned from blue to greenish-blue when they painted with the baking soda solution . It wasn’t an immediate change, but we could see it more as the eggs dried.
The kids loved watching how the colors changed as they used different solutions to paint! Our natural egg dye was a huge success!
For another great kitchen science experiment using red cabbage and eggs check out this Green Eggs Chemistry Experiment from Teach Beside Me.
The Science Behind the Red Cabbage Egg Dye Experiment
Red cabbage contains a chemical called anthocyanin that changes color depending on the acidity of its environment. This means it is a pH indicator, a gauge that tells you how acidic or basic the surrounding environment is.
Red cabbage is purple in a pH-neutral environment, but it turns pink in an acidic environment and bluish-green in a basic environment. We recently did another experiment with red cabbage where we froze cabbage-water into ice cubes and tested the acidity of different solutions. It’s the same chemistry, just a different way to see it.
Egg shells are made of calcium carbonate, which is a basic material on the pH scale. When egg shells are left in red cabbage juice, they turn the purple juice blue because they are basic!
Another way to see that egg shells are basic is by making naked eggs. When the shells are submerged in vinegar, they actually bubble a little bit, just like baking soda does when it is mixed with vinegar!