With Valentine’s Day just around the corner, I thought it was a perfect time to share with you a kitchen science activity you can use to send secret messages to your loved one!

How to use kitchen science to send a secret message

This is one of our kids' favorite things to do - there’s nothing like getting a blank piece of paper and making a secret message appear!

What you need

To make your secret message you will need the following:

• A blank piece of paper
• Lemon juice
• A Q-tip
• A heat source (Adults only: A burner in your kitchen or a candle will work well for this).

What to do to make your secret message

Here is how you make your secret message

1. Have the students dip the Q-tip in the lemon juice and use it to write a message on the paper.
2. Let the paper dry thoroughly.
3. Then, let the students watch as you reveal the message. (Adult Only) Hold the paper over the heat source until the message appears.  Remove quickly or the paper will burn.

What should happen

After the paper has been heated up, the message on the paper will turn brown, making it possible to read.

The acid in the lemon juice breaks down the paper a bit, thus weakening it.  The weakened paper burns before the rest of the paper, which is why you must remove it from the heat source just after the message appears or the entire paper will burn.

A few more kitchen science ideas

You can try the experiment again using water, which is neutral.  It should not degrade the paper the way the lemon juice does, so the message won’t appear.  You can also try writing messages with vinegar, orange juice or white wine, which will degrade the paper the same way the lemon juice did.