My kids love to play spy games. They spy on us, they spy on each other. They write notes in code and hide them all over the house. I knew right away that they would have fun with this science project. There’s definately enough 9-year old girl left in me to think it’s really cool too! This is a project that kids can actually do IN their science notebooks (or, they can just tape their note into the notebook when it is dry.) Like most projects, it doesn’t work perfectly. However, it is fun and you will see a message appear although it may be fuzzy.
All you need is paper, water, baking soda and grape juice. Simply add a few big spoonfuls of baking soda to a cup of water and mix it well (I heated the solution in the microwave to warm it in an attempt to dissolve more of the soda.) Dip a paint brush in the mixture and write a message or draw a picture on your paper. Let the paper dry completely.
When you are ready to reveal the secret code, have them paint over the paper with grape juice. Don’t use to much, or it will be a sloppy mess. The grape juice will react with the baking soda on the paper,changing the acidity of the grape juice and causing the words to appear a little darker than the background of the regular juice. Ours turned green. You could also try some different types of juice to see what happens. Have your kids record their results in their science notebooks! If they are interested, have them look up the definition for acid and base on a science website like chemistry.about.com.
The words weren’t very clear, but it was still a fun project and my kids loved it. Maybe your kids can perfect the technique. After all, trouble-shooting is a great life skill.