Invisible Ink Recipes for Kids | Classroom Detective Activities

Add invisible ink to your mystery or detective unit. Kids love it! These tested recipes are fun and easy.

Ms. Sneed Tries Invisible Ink Recipes

Our favorite fourth grade teacher, Ms. Sneed, sat at her kitchen table. She peered at her laptop.”Invisible ink recipes,” she said to herself. “Yeah, these will be a perfect addition to my mystery unit.”

Suddenly she jumped up and began to gather materials from around the house. First she took lemon juice, cranberry juice, and milk from the refrigerator. Then she pulled a box of baking soda from the cupboard. Next she pulled a pencil, a white crayon, some water colors, and a stack of paper from her school supplies. Finally, she took a hair dryer and some Q-tips from the bathroom.

Indentation Method

First, Ms. Sneed stacked two pieces on top of one another. Pressing firmly, she used the pencil to write, “It’s a mystery!” Then she removed the top paper and lightly shaded the bottom paper with the pencil. Sure enough, the message could be read easily.

“Yep. This is a keeper,” Ms. Sneed said to herself.

Kids can send secret messages with this indentation method. Stack several pieces of paper on top of one another. Press down hard when writing the message. Then send the indented version to a classmate.

Are you feeling “pinspired”? Feel free to pin images from this post.

White Crayon and Paint Method

On another piece of white paper, Ms. Sneed wrote “Clue #1” with a white crayon. Then she brushed over the words with some blue paint. The words popped out. “Wow, this is the best so far,” she commented.

For this version of invisible ink, write with a white crayon. The recipient of the secret message paints over it, and the words appear. Kids love it!
Heat-Activated Invisible Ink

Ms. Sneed decided to try heat-activated invisible ink next. She dipped a Q-tip in milk and wrote “Clue” on a piece of paper. Then, with a new Q-tip, she wrote “#2” with lemon juice.

After waiting for the liquids to dry, Ms. Sneed turned the hair dryer on high. She applied plenty of heat to the area where she wrote. “I can barely see the words,” she said to herself. “Therefore, the heat-activated methods are not a good match for my classroom.”

Baking Soda and Juice Method

Finally, Ms. Sneed mixed baking soda with water. Using a Q-tip, she wrote “Clue #3” with the paste. After it dried, she brushed cranberry juice over it. “Not bad,” said Ms. Sneed, “but definitely not the best method.”

To make invisible ink, write with a mixture of baking soda and water. After it dries, send the secret message. It can be seen after brushing it with colored fruit juice.

Students Experiment with Invisible Ink

When the time came, Ms. Sneed was ready with a fabulous invisible ink activity. “Today’s mystery activity,” she told her class, “is invisible ink.” Everyone cheered.

“Each science group will experiment with three methods. Then you will determine which is best.” The teacher distributed lab sheets and materials. After that, everyone got down to business.

Let kids try all three methods of making invisible ink. Then they can see which one works best.

As Ms. Sneed circulated around the room, she smiled to herself. What a great detective activity!

Enjoy Teaching

Over the course of her career, Ms. Sneed realized that there were 6 steps to enjoy teaching. In order to survive, she had to organize, plan, and simplify. Then, to thrive, Ms. Sneed needed to learn, engage, and finally – dive in! Follow the Fabulous Teaching Adventures of Ms. Sneed and learn how you can enjoy teaching too.

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