My kids have been asking me to start posting to our YouTube channel again for awhile now. But with school, activities, and family life I haven’t had time to do any activities with them. Now that school’s out for summer we all agreed to try to do at least one STEAM themed activity a week together.

We will record a video when we can and also share our STEAM activity to the blog. I’m still learning video editing and YouTube, but hopefully I’ll get better as the summer goes on! We hope you follow along with us both here on the blog and on our YouTube page. Here is a video we filmed to introduce ourselves:

Today’s experiment was our first STEAM activity of the summer together. We had some surprises and unexpected results that made it even more educational and fun!

We first tried using a hair straightener to reveal the secret message, but it didn’t work well. That was a great learning experience for all of us to see that sometimes experiments and hypothesis don’t work as expected. All we can do is come up with a new hypothesis and try again. We tried using the oven instead and it worked much better and quicker!

The hair straightener didn’t work as well as we hoped to reveal the secret message

I know your kids will love this super easy experiment as much as mine did, so keep reading to get all the details (and watch our YouTube video to see us do the experiment step by step).


This experiment requires you use a hot oven. An adult should complete this step and make sure you use proper safety equipment (like oven mitts) when moving the paper in and out of the oven. Don’t allow your children to place their hands near the hot oven, even though they may want to help.

This all probably seems obvious, but I forgot to use oven mitts in our YouTube video, and that was an embarrassing mistake. I could have burned myself and I wasn’t setting the right example for my children because the oven is very hot and dangerous. Please take oven safety seriously to prevent burns.


  • Lemon
  • Water
  • Small bowl or cup
  • Paper
  • Paintbrush
  • Oven (preheated to 425 deg F)


  1. Squeeze half a lemon into the small cup
My kids love using our lemon juicer to squeeze the lemon, but it’s harder than it looks (see our YouTube video)
  1. Add 1-2 teaspoons water to the lemon juice (optional – this will make the lemon juice appear more clear on the paper)
  1. Dip the paintbrush into the lemon juice and write or draw a secret message on the paper
  1. Allow the message to dry completely (this can take anywhere from 5-30 minutes depending on how much juice was used and the humidity)
This just looks like white paper but it has a secret message written in invisible ink!
  1. Adult: Place the paper in a 425 deg F oven for about 2-3 minutes, then carefully remove the paper and the secret message will be revealed!
My kids proudly displaying their secret messages

STEAM Concepts Learned:

The secret message reveal is caused by a chemical reaction called oxidation. Lemon juice contains carbon compounds. When it’s heated the carbon compounds release carbon which oxidizes in the air and turns brown.

This is a great experiment for the whole family: babies, toddlers, preschoolers, or elementary school kids will all have fun with this very easy, no prep activity!

If you watched our YouTube video you saw my baby daughter even got involved with this activity! She LOVED the lemon juice! We were so surprised by how much she liked it, but it was so fun watching her enjoy it.

My baby daughter loved the lemon juice!

Let us know if you like the videos and if you’ll try this experiment this summer. 🙂


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