How to make Invisible Ink!

Secret Messages - How to make Invisible Ink

by Sara Ahuir

Materials: INK: lemon juice, sugar, bicarb of soda, vinegar, salt and water.

PAPER

COTTON BUDS

TOASTER

1. Make up the solutions. You have to mix the inks with water inside a glass but with different glasses, except for the lemon juice and vinegar.

2. Write your message using different inks. You have to dip your cotton buds in the solution, then write the message using different pieces of paper for each type of ink.

3. Heat the paper with a toaster. Now, you take the paper and put it above the toaster to dry it. You have to be careful because the paper can burn.

4. What do you see?Why?Is it what you expected? We saw the solutions on the paper and we could see the messages that were written in vinegar, lemon juice, soda and sugar but we didn't see the one with water and salt. We saw this because sugar is a carbohydrate and it can carmalise and lemon contains sugar and proteins. Soda is an alkali and vinigar is an acid and it is unreactive. It is not what I had expected.