With Valentine’s Day just a few days away, roses are everywhere. Well, it turns out that roses are red, violets are blue… and roses can make acids look blue, too! Silly rhymes aside, this is a fantastic STEM lesson on acids and bases and pH indicators for elementary school kids.

To start, Travis needed to write a few secret messages. We filled one cup with a base solution (1 teaspoon of baking soda mixed with just a splash of water) and one cup with an acid (lemon juice).

Use a q-tip to write secret messages or pictures with each solution on plain white paper, making sure to use a separate q-tip for each. Let dry for at least 1 hour. Travis made a few designs his own, but I also left some secret hidden messages for him.

Now it was time to reveal those secrets! Travis rubbed a rose petal from our bouquet over the acid message I’d left behind to reveal this Valentine’s Day-themed word: love!

Yup, the rose petals act as a pH indicator and truly will turn the acid a bright blue, such a neat reveal!

Unfortunately, we weren’t able to clearly see the messages we’d left behind in the base, so perhaps our baking soda mixture was too watery. I had hoped for him to reveal a smiley face.