Have you ever dreamed of being a spy like James Bond or Jason Bourne? An old-fashioned staple of the spy is being able to encrypt and decode secret messages. Start your espionage now with this quick and easy recipe!
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DIY INVISIBLE INK
SAFETY KEY:
+ Dangerous liquids
SKILL LEVEL:
EASY
INTERMEDIATE
ADVANCED
APPROXIMATE TIME:
15 minutes
WHAT YOU’LL NEED:
+ Paper
+ Lemons
+ Bamboo sticks/stylus pen
+ Electric stovetop
+ Paper towel
+ Spray bottle
+ Lighter
+ Baking soda
+ Grape juice
+ Cup or plate
+ Bleach
+ Ultraviolet flashlight
LET’S BEGIN
We are going to make three types of ink.
LEMON JUICE INVISIBLE INK
1. Squeeze a lemon (or buy pre-squeezed lemon juice from the store) into a glass or onto a plate.
2. Dip a bamboo stick in the juice.
3. Bring the stick over to a sheet of paper and slowly write a message. Re-dip in the lemon juice as often as needed.
4. To reveal your message, carefully move a lit lighter back and forth under the paper, or move the paper over the heat of an electric stove top, making sure not to burn the paper. When the paper is properly heated, the message will appear.
ALSO TRY: Use an old-fashioned fountain pen to see how this affects the appearance of your mysterious messages.
BAKING SODA AND WATER INK
1. Mix equal parts baking soda and water.
2. Using the bamboo stick again, dip it in the mixture, and write your message.
PRO TIP: Use a paper towel to blot excess liquid.
3. Put some grape juice in a small spray bottle and spray it on the paper. It tastes good as a juice; now let’s see if it’s a good secret-message revealer.
4. Your message should be revealed. How does this compare to the lemon juice?
BLEACH INK
1. Pour a small amount of bleach into a cup or onto a plate.
2. Dip your bamboo stick in the bleach and write a message.
In theory, the bleach is supposed to glow and be reflective under an ultraviolet flashlight. However, the paper around it actually glows and the bleach stays nice and dark.
3. Wave the ultraviolet flashlight over the message and it will appear.
The coolest part about the ultraviolet flashlight is that the message only appears there when it has the light on it, unlike the lemon and grape juice messages, which reveal the message permanently once you’ve gone through all the steps. With the ultraviolet flashlight method you can also see what’s on the paper as you’re writing it!
WHAT’S YOUR FAVORITE METHOD? Now that you’ve tried all three methods, think about which one would be your go-to method if you were actually a spy. You’re one step closer!
FUN FACT: Invisible ink was first mentioned by Aeneas Tacticus in the fourth century BC in his book How to Survive Under Siege.