Using Poinsettia Leaves as an Acid / Base pH Indicator

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I LOVE this fun holiday activity!

We science teachers know that many plants contain pigments that can be used as pH indicators.  I think we have all created a stink in our homes or labs by boiling red cabbage to use the "juice" as an acid/base indicator!



Did you know that you can do the same with the pigments found in red Poinsettia leaves?

These plants contain anthocyanins, which are water soluble pigments.  These pigments are responsible for the the red, purple, and blue colors seen in flowers, fruits, and vegetables. Anthocyanins respond to changes in pH.  I absolutely love lab activities that use items like this in the lab.  My students are often surprised and excited to discover that household items, such as the Poinsettia or red cabbage, can be used for scientific purposes.  Using the Poinsettia leaves as an acid/base indicator makes for a super fun lab activity around the holidays.

In this lab, the students will use a pigment solution extracted from the leaves of the poinsettia to establish a known pH baseline.  Students will then use this baseline to predict the pH of common household items.

The images below will give you a great idea of all that is involved with this lab. Click on any image below to view this resource in my TpT store.

I hope you find this useful in your science classes.  Enjoy the holiday season!