Poinsettia pH Experiment - Christmas Around the World for Kids - Mexico

This is the third activity in our Christmas Around the World for Kids series! Today, we're looking poinsettias and traditions in Mexico!

One of the most exciting Christmas traditions in Mexico is the posadas celebration Las Posadas.

It celebrates the birth of Jesus with parades and parties from December 16th until the 24th. Each night, a procession of children travel the street knocking on different doors and asking for a room to stay, representing Joseph and Mary looking for a room. They are turned away from several doors until they land at the final room for the evening, where they are welcomed inside for a party. During the party a piñata is broken and friends and family celebrate. The largest celebration is, of course, on the 24th, representing the night Jesus was born.

I debated making piñatas for our Mexico "visit," but there is one other tradition that I wanted to highlight as well: the Christmas Flower.

Poinsettias are the Christmas Flower in Mexico, and they bloom beautifully in December! There is a story that this tradition comes from a Christmas miracle when a small child could find nothing to give to the baby Jesus at the end of a procession, so she lovingly placed a bundle of weeds on the alter. The weeds transformed into the beautiful blooming poinsettia flower.

This story is retold beautifully in The Legend of the Poinsettia by Tomie dePaola. I also have very fond memories of beautiful poinsettias during the Christmas season when I was a young child in southern California, so I decided we would read the story and do a poinsettia-based science experiment for our Mexico visit.

Here's what I used:

** Picture books (I shared the Legend of the Poinsettia before we did the experiment and saved Lily Huckleberry in Mexico for later.)
** Poinsettia
** microwave-safe bowl
** pipettes
** Poinsettia pH Scale (below)
** chemicals to test
** test tube well tray (you could also use test tubes or even a white plate)

Poinsettia pH Experiment:

Red poinsettia leaves have anthocyanins in them. These chemicals give the leaves the red color. They also change colors when they are in solutions with a different pH.

I tell my kids that the pH scale measures the concentration of hydrogen atoms in a solution. This is a slight simplification, but it is enough for middle school and elementary aged kids, and it prepares them to get a few more details in high school. 

Anyway, the pH scale generally goes from 1-14. Low numbers are strong acids, 7 is neutral, and high numbers are strong bases.

The anthocyanin molecule literally changes shape (and color) depending on the pH of the solution it is in. When it is in acids, it turns pink. When it is in bases, it turns a yellowish-green. When it is in a neutral solution, it turns an almost colorless violet.

To test household chemicals, we want to extract the anthocyanins out of the red leaves. This is actually easier than it sounds--just tear up the leaves, add a bit of water, and boil it for a minute or two!

We tore up 6 leaves and added about 3/4 a cup of water:

It only takes 3 minutes in the microwave:

Next we started testing chemicals. Even using household chemicals, please use the following precautions with kids:

If it can splash or break, wear goggles.

To test, put a few drops of your chemical in a well (or on a plate) and add a few drops of the poinsettia water (now an indicator). You can tell if your chemical is an acid or a base by the color it turns.

We tested the following acids: hydrochloric acid, lemon juice, orange juice, lime juice, and vinegar (acetic acid).

We also tested the following bases: sodium hydroxide, bleach, rubbing alcohol, and baking soda solution.

After we finished we had nachos for lunch and put our Mexico "stamp" in our "passports." (You can print a free set HERE.

Then, of course, we set up the poinsettia as a decoration for the rest of the month!

(Sidenote: This experiment is also included in the 25 Christmas Science Experiments ebook that I wrote several years ago! It's a short and sweet book with easy-to-follow directions for 25 fun, classic experiments with a holiday twist!)

We are learning about Christmas around the world this year with 12 different activities--this was the third one!  I would LOVE if you joined us!! I will be linking all the activities to THIS PAGE, so you can pick and choose which to do. There's also a link to get the passport that I made there (for free) and a giveaway that will run from December 1st-16th!  And, I'll be linking to a new Christmas Around the World for Kids activity each week day until all 12 are up!

And if you're looking for more homeschool unit studies, be sure to check out our growing collection here!

Happy Educating,
Carla & the kids who don't sit still!