Decode invisible writing with science!

When I was a kid, I loved writing to my cousins who lived “far away” in Dallas.  Allie had such a great time with her cousins over Christmas that we decided to write to them.  But what could make note writing even more fun?  Invisible ink! And the best part was, I had invisible ink right in my refrigerator!

We put a few squirts of lemon juice in a bowl, dipped cotton swabs in the juice, and wrote on white cardstock. After a few minutes the lemon juice writing dried and disappeared!  Then, we should have folded up the notes and mailed them with decoding instructions.  But my curiosity got the best of me.

I told Allie that we were going to make the notes reappear with science.  Her ears perked up and she forgot that we were supposed to be mailing them.  I warned her though that the writing would undergo a chemical change and could not be reversed.

Then I proceeded to decode our letters holding them over the burner on the stove.  The paper and my fingers got a little too close to the heat but what mom doesn’t get singed every now and then for science?  Next time I’ll use tongs!

What happened:  When lemon juice is exposed to heat it oxidizes and turns a darker color.  Oxidation was the chemical change that decoded our secret messages!

So, we are sending these notes to our cousins via this blog because decoding invisible writing should be done with caution. One of these days, I hope Allie enjoys handwriting notes as much as I do – with visible or invisible ink!