Invisible Ink (Creative Chemistry Experiments)

You will need:

1. Spoon
2. Bowl
3. Paintbrush
4. A lemon
5. Water
6. Lamp or other lightbulb

Secret notes written in invisible ink can’t be read. You can just as easily write a letter to your friend with invisible ink, using very simple ingredients. The results, however, are anything but simple. Enjoy coded letters and messages with your friends through this project.

INSTRUCTIONS

1. Squeeze half a lemon into a bowl and add a few drops of water to it.
2. Stir this mixture well with a spoon.
3. Dip the paintbrush in the lemon-water mixture and write your secret
   message on a piece of white paper.
4. Wait for the message to dry completely
   so that it may turn invisible.
5. When you want your friend to read the message, simply ask him to hold the paper under a bright hot lamp or lightbulb.

RESULT

Words appear magically on the piece of white paper because lemon juice, which is acidic in nature, oxidizes when exposed to heat, turning the juice brown.