Detective Academy: Challenge 4

The Challenge

Create your very own invisible ink!


  • Water
  • Baking soda
  • Cotton swab
  • Grape juice or grape juice concentrate
  • Cotton round/pad


Step 1

Using a small bowl or cup, mix together ¼ of a cup of baking soda with ¼ of a cup of water.

Step 2

Using the cotton swab or paint brush, begin to write your sentence on a piece of paper. Use the baking soda and water mixture as ink!

 Step 3

Allow your piece of paper to dry before revealing the secret message.

Step 4

Gently wipe grape juice over your dry piece of paper using a cotton round\pad or paintbrush.

Final Step

Your secret message should appear on the paper!

Good luck, Detectives!

If you need something to keep you busy until next week’s detective academy, check out some of our other posts!

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