Red Cabbage as a Natural Egg Dye
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.
Total Time: This experiment takes awhile, though you don't have to actively be doing anything for most of the time. Allow about 40 minutes to boil the eggs and cabbage and at least 12-18 hours for the eggs to sit in the fridge in the cabbage solution. Painting the eggs only takes 10-20 minutes at the end.
Safety Concerns: As always, be careful when boiling things with kids around. Use caution when cooking and handling the hot eggs and cabbage.
Materials You Need:
One half of a head of red cabbage
One dozen large eggs
Slotted spoon
Lemon juice or vinegar
Baking soda
Q-tips or paint brushes to paint the eggs
Directions:
To prepare the eggs:
- Place eggs in a large pot in a single layer.
- Chop up your cabbage into small pieces and throw them into the pot with the eggs. Add enough cold water to cover everything by one inch.
- Bring the cabbage/eggs/water mixture to a boil. Remove from burner and cover the pot.
- Let your mixture stand for about 12 minutes for large eggs (9 minutes for medium eggs, 15 minutes for extra large eggs).
- Using a slotted spoon, remove your eggs from the pot and cool completely under cold running water or in a bowl of ice water. They will most likely still be very white at this point.
- Refrigerate your eggs. Once your cabbage water has cooled to room temperature, place your eggs back into the pot and refrigerate everything together. Make sure the eggs are completely submerged in the water for best color.
- Leave your mixture in the refrigerator overnight.
- Use a spoon to scoop your eggs out of the cabbage mixture. Feel free to rinse them off and pat them dry. They should be some shade of bluish-purple (depending on how acidic your tap water is!).
- Pour some lemon juice or vinegar into a small cup (this is your acid).
- In another cup mix 1/2 tsp baking soda with enough water to dissolve it (this is your base).
- Using your Q-tips or paint brushes, paint your eggs! Watch as your eggs change from blue to pink when you paint with lemon juice and from blue to greenish-blue when you paint with your baking soda solution (this may not show up well until the eggs are dry again).
- Feel free to try painting your eggs with other solutions from around the house to see what happens. Some ideas to try are washing soda, cream of tartar, and antacids. If your egg turns pink you know the solution is acidic, if it turns green you know it's basic!
STEM Saturday
Amazing Easter Science Experiments from Frogs and Snails and Puppy Dog Tail
We want to see your best STEM Activities! That means show us your best Science, Technology, Engineering, and Math posts! By linking up, you are agreeing to be featured in future blog posts and allow us to use one image from your posts. Feel free to link up to 3 activities each week, and show others some love.
No comments:
Post a Comment
Be awesome. Leave a Comment.