This project explores the chemistry of acids and bases by using them to create invisible ink. Students will write secret messages using acidic solutions and reveal them by applying a basic solution.
If an acidic solution is used to write a message, it will become visible upon application of a basic solution due to a change in pH.
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Mix lemon juice with water in one bowl to create an acidic solution.
Dissolve baking soda in water in another bowl to create a basic solution.
Use a cotton swab to write a message on paper with the lemon juice solution.
Allow the paper to dry completely.
Apply the baking soda solution over the message with a paintbrush.
Observe the message become visible.
Repeat the process, experimenting with different acids or bases.
Record observations and compare results.
The acidic message should become visible after applying the basic solution, showing how pH changes can reveal hidden signs.
Type of acidic solution used
Visibility of the message
Type of paper, Application method, Concentration of solutions
Avoid contact with eyes and skin when mixing solutions, and wash hands thoroughly after the experiment.
Demonstrate the experiment live to engage the audience.
Explain the chemistry behind acid-base reactions in simple terms.
Provide sample messages for the audience to decode.
Yes, many household liquids like vinegar can also work.
The reaction between the acid and base alters the paper's pH, changing its color.
Repeated applications may weaken the paper; use sturdy paper if needed.
