Oh, the Ways We Can Think… to Use Invisible Ink!

Invisible ink pens with UV lights are relatively inexpensive. The link in this article is an affiliate link. Read more HERE.

Kids love receiving and writing TOP SECRET messages!

Not too long ago, I created an outdoor scavenger hunt for my two grandsons using invisible ink pens. We had so much fun, it prompted me to think about how invisible ink could be used in the classroom.

Here are a few ideas to get us started:

(1) REVEAL THE ANSWER – If you have students self-check as they work on math problems or puzzles, you could post an answer key on your wall with the answers written in invisible ink. Students use the UV light to reveal the solutions and check. This could also be a fun way to share answers to riddles or problems of the day– even posted on a bulletin board. You may not use flashcards much, but they could be even more fun with answers instantly revealed.

(2) CRYPTOLOGY LESSONS and UNITS – This seems to be an obvious application, but if I were doing a unit such as this one, I would probably incorporate some kind of hunt or activity with a few coded messages written in invisible ink or deciphered with UV flashlights.

(3) GUESSING GAMES– Imagine the students playing Battleship (using grid paper) with ship locations marked in invisible ink! Less cheating, maybe? Here’s another idea: At the beginning of the year, write student names on name tag stickers using invisible ink. Have them walk around and learn one another’s names by shining a UV light on the name tag. The goal is to see how long it takes them to learn everyone’s names without shining any lights. This idea could be applied to any guessing game, and could also be a way to provide hints. Write hints out on cards in advance and post them around the room for students who need them.

(4) KEEPING IT PRIVATE – Student passwords, login usernames, and even special messages from the teacher would be kept private if written in invisible ink. If you draw names for prizes or privileges, you could write student names on cards using invisible ink and guarantee a fair draw!

(5) SIMULATION – Use invisible ink to simulate infrared light, bioluminescence, or any natural phenomenon (e.g. glowworms, fireflies, etc.) It could be fun to show glowing eyes on Jack-O-lanterns and cats in October.

The idea of using invisible ink in simulations has inspired me to create a new “Wildlife Search and Rescue” Progressive Puzzle. Students learn a little about thermal imaging and then use the puzzles to determine the location of an animal that’s escaped from a wildlife park. Invisible ink pens with UV lights are optional, but add an element of fun and surprise!

If you think of ways to incorporate invisible ink in the classroom, share in the comments below or join our Facebook group to comment on this post. It could be a fun and novel way to engage students if used sparingly!

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