So, it’s been rainy lately, to say the least. Why not try a fun new activity while cooped up indoors, and learn a thing or two while at it? Here are two fun ways to share secret messages with your friends. They will only be able to see the message once they “unlock it,” since it’s written in invisible ink!
Option 1: Using grape juice
You will need:
- Baking soda
- Water
- Grape Juice
- A cup for mixing
- Cotton swabs (Q-tips) for writing
- White paper
To make the “invisible ink,” mix ¼ cup of baking soda with ¼ cup of water in your cup. The measurements don’t need to be exact, as long as you have equal amounts of each ingredient.
Using this mixture, write your secret message on the paper with a Q-tip, and wait for it to dry.
To reveal the message, take another Q-tip, dip it in grape juice, and paint over the area.
Why does it work?
The baking soda used in the “invisible ink” is a type of chemical called a “base,” and when the grape juice is added to the base on the paper, they react to each other. A chemical in the grape juice changes to become darker, which is why the message can be seen in a darker purple (compared to the lighter purple on the rest of the paper).
In a lab, sometimes scientists need to be able to test if a chemical is a base. To do so, they combine the chemical with an indicator, which they know will change colour once mixed with a base. Guess what? One of the ingredients in grape juice – called an anthocyanin – works as an indicator!
Option 2: Using white crayon
Option 2 is easy, and a bit more straightforward. You will need:
- White crayon
- White paper
- A highlighter or marker, or
- Watercolour paint and a paintbrush
Write your secret message using the white crayon on a piece of white paper. Try to write as heavily as you can, this will make it easier to read later. The crayon writing will be invisible (white on white).
When it’s time to reveal the secret message, colour the area surrounding the message with highlighters, markers, or watercolour paint. Try using different colours to see which you like best, just be careful to not make a mess on the table!
Since the crayon leaves wax on the paper, the paint or ink from the marker or highlighter won’t be able to stick to it, leaving the message visible.
Picture credit: HubPages Education
