Let's learn how to write your own secret messages using invisible ink.
ATTENTION: Adult supervision is needed when using the iron.
What You Need
- Cotton swab (Q-tip)
- Lemon Juice
- Orange Juice
- Grape Juice
- Desk Light with Bulb or Iron
What You Do
- Write a message on a piece of paper with lemon juice using a cotton swab. Be sure to put it on thick.
- Let it dry.
- Use the iron to make the messages appear. Why does heat work?
- Try some other juices. Do they work? Why or why not?
The Science. It's a chemical reaction! An organic substance will turn into black carbon when heated. Lemon juice is acidic and weakens the paper. When the paper is heated, the remaining acid turns the writing brown before discoloring the paper.
Use the following resources to learn more:
- How to Make an Invisible Ink Message
- How to Make Invisible Ink with Lemon Juice
- Invisible Ink with Lemon Juice
- Lemon Juice Invisible Ink
- Make Invisible Ink