Invisible ink

This funny experiment will show you a new way to pass your messages on to your friends secretly. Learn the secret of invisible ink!

How does it work?

The citric acid is the most important here. It is the main componant of lemons. The citric acid is made of carbon, among others, which is colorless unless it is heated, then it becomes brownish. Moreover, it burns much quicker than paper.

When you move the message over the flame, it heats the lemon juice and therefore the citric acid will burn, oxidize and become brownish. Now you can read the secret message.

Necessary materials

• Lemon juice
• A small dish
• A sheet of paper
• A Q-tip
• A tea-light candle

How to make this experiment

1. Pour some lemon juice into the small dish.
2. Dip the Q-tip into the lemon juice, and write a message with it on the sheet of paper.
3. Wait for it to dry.
4. Ask an adult to light the candle, and to move the paper over it. Make sure the paper does not burn!
5. After a while, you will see your message appear !