Secret Messages With Invisible Ink!

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Here's how.

Active Time

20-30 minutes

Total Project Time

45 minutes to 1 hour

Key Concepts

Chemistry, acid, base, chemical reaction

https://www.youtube.com/watch?v=AOVD7WgFP2s

Introduction

Have you ever wanted to send your friend a secret message that no-one else can read? Then you might know of invisible ink—a special type of ink that you can use for writing and that does not show up on paper. Only after a special treatment will it appear again magically, and the message can be read. How does this work? Find out in this activity and write your own secret messages!

Credits

Svenja Lohner, PhD, Science Buddies

This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.

Next: Materials

Materials

Tools:

Cardstock
Measuring spoons
3 cups or small bowls
Spoon
Q-tips or a brush
Old newspaper or cardboard
Paper Towels

Method 1:

Water
Lemon or lemon juice
Iron

Method 2:

Baking soda
Water
Turmeric and rubbing alcohol OR concentrated grape or blueberry juice. Note: Instead of rubbing alcohol another high percentage alcohol (40 percent or more) can be used. Water does work as well but the results won't be as intense.