invisible ink experiments, invisible ink recipe, invisible ink for kids

Spy Kit: Mission 7, Part 2

Spy Kit for Kids 

CALLING ALL AGENTS - INCOMING MESSAGE: Quick! You’ve just received an important message from a fellow spy. You’ll need to decipher it before anyone sees it! Follow along with this next experiment to make the top-secret Invisible Ink Revealer…

How do you use purple sweet potato powder?

Our top secret ingredient is the purple sweet potato powder! You’ll see as the potato powder reacts to the sodium bicarbonate (baking soda)… A new color will form where the letters are in the message. Make sure the invisible ink message is completely dry before you apply the Revealer. 

How to Make Invisible Ink Revealer:

1. For this experiment, you’ll need the sweet potato powder, yellow spoon, a feather, and water.

Materials of Invisible Ink Revealer


2. Scoop 3 large spoonfuls of purple sweet potato powder into the test tube.

Scoop 3 spoonfuls of baking soda into the test tube


3. Add enough water to almost fill it and leave about ½ inch from the top. Look how pretty the purple substance looks! Screw the cap on tightly and shake the solution. 

Add enough water to almost fill it and leave about ½ inch from the top


4. You’ve made the Invisible Ink Revealer! Just like the invisible ink, this solution will try to separate - make sure to shake the solution in between uses.

Reveal your secret message from page 3


5. Take your feather and dip it into the test tube. Feather side first! This will act like a makeshift brush. TIP: Pinch the tip of the feathers down first to fit into the tube. Continue to pinch along as you insert the feather farther down. 

Dip the feathers from your quill down into the test tube


6. Gently wipe the purple solution over the dried secret message. Can you read it? What does it say? SHHH! Don’t tell… keep all the secrets. 😉

Practice writing a few messages to really get the hang of it. Start with larger letters first and perhaps use one of your secret alphabet codes next!

Gently wipe the revealer solution over secret message

Take a look at this video to see how to create the Ink Revealer from start to finish!


What is the best Spy Kit?

Spy Kit form Learn & Climb! Solve puzzles, test out science experiments, make spy gadgets, and more?! There are 55 TOTAL activities to ignite critical thinking skills! link to spy kit

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