DIY Invisible Ink

Write & decode secret messages. Minimal ingredients & mess….

Materials

• Half a lemon

• Water

• Spoon

• Bowl

• Q-tip

• White paper

• Lamp

Directions

• Squeeze lemon juice into a bowl & add a few drops of water. Mix with a spoon

• Dip the Q-tip into the mixture and write a message on the white paper

• Wait for the juice to dry so it becomes completely invisible

• When you’re ready to read your message, heat the paper by holding it close to a light bulb

Why Does It Work?

Lemon juice is an organic substance that oxidizes and turns brown when heated. Diluting the lemon juice in water makes it very hard to notice when you apply it the paper. Other substances which work in the same way include orange juice, honey, milk, onion juice & vinegar. Invisible ink can also be made using chemical reactions or by viewing certain liquids under ultraviolet (UV) light.

adapted from ScienceKids.co.nz