The Chemistry Behind Invisible Ink

Hola! Enough of those biological principles! :) I would like to introduce you to the chemistry of the invisible ink and how it works so we will all be familiar with the principles underlying this wonderful Science. Many household products can be used to make this experiment but some that remains popular are lemon juice ink, baking soda and corn starch. Inferring on their pH content, these substances are basic and acidic substances. To the best interest of everybody, the principle behind invisible inks is the process of weakening the molecular bond that holds cellulose together (polysaccharide, glucose molecule) that makes up the paper material. The application of the acidic substances or basic substances weakens the part of the paper where the basic/acidic substance was applied to and made visible when passed over a flame or a hot object or when heat is directly applied to show the damaged part of the paper. I have searched some experiments online which you can use with your students or when making clandestine dates with your girlfriends or boyfriends or sending secret messages. Hehe. Pretty cool, huh! Please use the links below and paste it in your external browser's address field for detailed instructions on how to prepare this cool stuff. :) Enjoy!

Jules

Chemistry of Invisible Ink: http://chemistry.about.com/b/a/207468.htm?nl=1
Lesson Plan on making Invisible Ink: http://www.iit.edu/~smile/ch9602.html