- Lemon juice
- 2 Bowls
- Pour out some lemon juice into a bowl
- Using the lemon juice as 'ink' a write a message (using a paintbrush) onto the paper
- Wait for your message become invisible and dry completely
- In the other bowl mix together 2 tablespoons of iodine and ¼ cup of water
- Coat the paper with a thin layer of the iodine solution
- After approximately 5 minutes the message should show up
- Paper contains starch and iodine is used to test the amount of starch in an object. This is why the paper turns purple.
- The lemon juice stops the color change.