Invisible ink isn’t just for spies—you can write your own secret message right in your kitchen! Check out this cool way to learn about chemicial reactions, using ingredients from your own home.
Why does this work? Lemon juice is an acid and weakens the paper. The salt and crayons are a base. When these two chemicals mix together they react and the base helps you see the acidic message!
Activity best for ages 4 and up (with adult supervision)
Materials
- 1 piece of blank paper
- 1 cotton swab
- Half of a lemon (juice squeezed into a bowl or dish)
- Salt
- Crayon
Questions to answer while experimenting
What do you think will happen when you mix these materials together?
Why do you think you can see the message?
How could you use this experiment to help you in the future?
Directions
Step 1
Think of a message you want to write to a family member.
Step 2
Dip your cotton swab in the lemon juice and write your message on the paper.
Step 3
Sprinkle salt all over your drying lemon “ink.”
Step 4
Once the message is dry, use a crayon to color over the paper and reveal your secret message!
Be sure to share your secret messages with us on Instagram by tagging @sdcdm320.
Do you have questions about this activity? Email Education@sdcdm.org