One day, I was looking at the book, Crafty Science by Jane Bull. It has a bunch of STEAM projects for children to create at home. I showed my son the Invisible Ink activity and he said “Let’s do that mommy.” We looked around the house and gathered the materials.

I thought this would be a great drawing and writing activity for my son. He ended up writing numbers. This is a great project to expose your child to literacy and science. If your child is learning how to read, write words that will challenge them to use phonics or sight words. The science in this project is explained at the end of this post.

Let’s Get Started!

Invisible Ink


  • Lemon
  • Bowl
  • Paintbrush or Cotton Swabs
  • Paper
  • Iron (for adult use only)
Materials for Invisible Ink Activity.


Squeeze a lemon into a bowl

Write your secret message on the paper in lemon juice using a paintbrush or cotton swab.

Draw quickly in order to check your work before it dries. It does not have to be as dark as the picture below. My son insisted on going over the numbers numerous times so he could see it.

To get the message, an adult should iron the paper with a hot iron until the message comes through


  • This activity may stain your iron with brown spots. This happened to me. I was able to get my iron squeaky clean by following the video below.

Why this activity Works:

  • This works because lemon juice is an acid.
  • When it is put on the paper, the acid destroys some of the paper surface.
  • When you heat it up with the iron, the areas with the message turn brown first.
  • Milk also works with this activity because it is slightly acidic.

Have fun with this simple activity!

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23 thoughts on “Invisible Ink Writing/Drawing Activity

  1. Well I have never heard about invisible ink activity before. This is really new concept for me. I will definitely try with my little one. Keep sharing such insightful posts

  2. I knew about the lemon juice but was not aware this would work with milk as well. Thanks for including the video about getting the iron clean afterwards!

    1. No problem! I was devastated when my iron turned brown. I just wanted to make things easier for your all! Thank you for your comment.

  3. My girls would love this. Currently my oldest daughter is in an after school STEAM program and she just loves all the great activities so we are searching for more to do at home. Will have to give this one a try. Thanks so much.

    1. Oh good! I hope your daughter likes the activity. STEAM projects are hands on and fun!

    1. Thank you for your comment Ana! I am so happy you like it. I hope you all have fun with this!

  4. I remember doing this as a kid but had forgotten all about it. Definitely adding it to our project list!

    1. I love oldies but goodies! I hope you all have fun with this activity! Thank you for commenting.

  5. I like how this activity is fun and you get to learn something as well. I great idea to do on a rainy day! Thanks for sharing!

  6. Great activity! I remember doing something similar as a kid, and having so much fun with it! When we did it, we held the paper over a candle to get the magic ink to show up. Made me really feel like a spy from the olden days of knights and royals!
    (And ps: I love that you included the little warning about the iron and how to fix it!)

    1. Oh wow! That sounds like fun to hold it over a candle. Thank you for the tip. Thank you for commenting.

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