Make invisible ink at home!
How to make an invisible ink message
Make your own invisible ink!
Wear protective gloves, eyewear, and a mask. Perform this experiment in a well-ventilated area.
Reagents and equipment
- 5 mL 1M copper(II) sulfate solution;
- 2 mL 10% ammonia solution;
- a cotton swab;
- a Petri dish;
- a plastic cup;
- a piece of white paper.
Use the cotton swab to write a message on the piece of paper with the 1M copper(II) sulfate solution. Notice that the message disappears as it dries. To reveal the message, put a few drops of 10% ammonia solution into the Petri dish and set the paper over the Petri dish. The message should appear within 5 minutes.
Since the copper(II) sulfate solution is light blue, it disappears as it dries. When exposed to ammonia vapors, copper(II) ions react with the ammonia to form a dark-blue complex.