Invisible “Ink”


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!  What could be more fun than invisible ink?  This is a project that they can actually do IN their science notebooks (or, they can just tape their note into the notebook when it is dry.) 

There is one caveat.  Like most projects, it doesn’t work perfectly.  So, if you feel your child will get too frustrated, choose another experiment.  However, it is fun and they will see their message appear although it may be fuzzy.

All you need is paper, water, baking soda and grape juice.  Simply have your child add a few big spoonfuls of baking soda to a cup of water and mix it well (I heated it in the microwave a little to try to dissolve more of the soda.)  Using a paint brush, have them write a message or draw a picture.  Let the paper dry completely. 


When they are ready to reveal their 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.  Your child could also try some different types of juice to see if it made any difference.  Have them 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   img_19712

 As I said, the words weren’t very clear, but it was still a fun project.   Maybe your kids can perfect the technique with their own ingenuity.  After all,  trouble-shooting is a great life skill.

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