Do you ever feel the need to write a message that no one will see - unless they know how to look? Try an old trick out of the spy playbook and give invisible ink a try! It’s fun, simple to make, and actually be quite useful. Plus, invisible ink is all about chemical reactions, so it’s a great way to get kids involved in some simple science. Here’s how to make your own invisible ink at home:
1. Decide on how you want the message to be read.
Some invisible inks can be revealed using heat, while others use chemical reactions and ultraviolet light. The easiest method is heat, which will narrow down your ink choices.
2. Choose your ink based on your choice from Step 1.
Generally, if it affects the structural integrity of the paper you’ll be writing on, it works as an invisible ink. If you’re going with heat activated inks, some options include lemon juice, baking soda, milk, and honey. If you want to use a chemically activated ink, you can try table salt, starch, or vinegar. Each of these requires its own chemical “activator.” For example, table salt can be developed (revealing the message) using silver nitrate.
3. Write your message, then see if you can read it!
Grab your ink, write your message on the paper using a cotton swab or your fingertip, let it dry, and voila! You have successfully written with invisible ink.