Using Poinsettia Leaves as an Acid / Base pH Indicator

Click image to view this resource in my TpT store.

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!

5 Ways to Encourage Awareness of Global Science Issues in Your Classroom

It's easy and it doesn't take

 much time!

It's time for the Secondary Smorgasbord Blog Hop event for November.  I was super excited when I discovered that the theme for this month is "Creating a Global Classroom."  I have been involved with a few things just this month that are perfect for encouraging a sense of global awareness in the science students we teach.

Is it really so important that we encourage and teach global awareness in our science class?  I think the answer to that is an emphatic YES!  Making students aware of world issues and teaching them to get involved is important, but it doesn't fall naturally into our curriculum, and we have to really make special efforts in our planning to work it into our teaching.  I am just like every other high school science teacher ..... I fell pressure to teach, teach, teach concepts and details because it might be on the end of course test or on the AP exam.  I always feel like I can't spare a minute of teaching time on something that might not be on a standardized test!  (We will save the discussion of standardized testing for another day!)  The bottom line is that we will have to make adjustments and do some creative planning to incorporate other concepts and ideas that fall outside of our curriculum.

So without further ado, here are 5 things you can do in your classroom to increase global awareness.

1.  Start at home.  Students need to get involved with service projects within their own communities.  Nothing brings a deeper awareness and empathy for others than being involved with it on a personal basis.  Here is one activity (free download) that I do during the holiday season.  My "Dichotomous Key to Holiday Giving" is a fun science activity that involves a dichotomous classification key.  The students get a refresher in the concepts of classification, and our local food bank gets stockings filled with treats that they can dispense with their other food items.  Check this blog post for more details.

2.  Start your preparations for Earth Day now!
What??  It's only November and Earth Day is in April!  I know, I know!  But you can't incorporate effective Earth Day activities if you don't start now. The perfect time to begin your teaching and lessons on Earth Day is when you return to the classroom in early January.  Use this free Earth Day PowerPoint to tell your students about Earth Day and why it is important.  Then brainstorm ideas with your class about what you can do.  You might plan to plant some trees, clean up an area of neglected highway, or help your community with some new landscaping at the local park.

3.  Take a virtual field trip with The Nature Conservancy.  Several times a year, you and your science class can go on a live, virtual field trip to an amazing ecological location.  The next one is coming up soon, and you can get the details from a blog post I have just written.  Each field trip includes outstanding video footage and free downloadable lesson plans.  If you can't participate in the live event, all of the field trips have been archived so that you can use them at your convenience.  Check out this link to NatureWorks Everywhere for all the possibilities.

4.  Use a curriculum that teaches about a global science issue.  "Keep Wild Animals Wild" is a program that I have recently thoroughly investigated.  The curriculum is free and is for grades K-8.  The materials are specialized for grades K-2, 3-5, and 6-8.  Use this link for a detailed description.  Students will learn of the problems facing Earth's fragile ecosystems, habitat destruction, climate change, and the illegal wildlife trade.  These are certainly global issues that students need to be made aware of.


5.  Make use of the many, many online resources that are available that teach about global science issues. Try to devote the first few minutes of your class for a current event article, or show a short video to raise awareness.  Here are links to some of my favorite sites:

Smithsonian Science Education,   PBS Science and Nature,   National Geographic,   Science Illustrated,   Discover Magazine,   BBC Earth, and Scientific American.    

A Dichotomous Classification Key with a Holiday Twist!

Combine how to teach (or review) a dichotomous classification key with a wonderful community service project!

I absolutely love the holiday season for so many reasons, but one of my favorite reasons is that I look forward to this activity with my biology students so much!  I came up with this idea several years ago while racking my brain for an activity that could be done with my high school biology students just before the Christmas break.  I wanted to involve my students in a community service activity and also wanted it to be related to science in some way.

Starting this week, in the few days before we dismiss for Thanksgiving holidays, I will place a collection box in my classroom.  I tell my students that we are going to collect money for a project that will benefit those less fortunate than we are.  I encourage them to give what they can.  I let them know that we will be collecting money for several weeks.  Since most high school students usually have a bit of change in their pockets, I encourage them to place some coins in the box whenever they feel they can spare it.

After a few weeks, I use the money to buy various candies (Hershey bars, Reese's peanut butter cups, peppermint patties) and travel size toiletries (shampoo, deodorant, toothpaste, etc.) Then one day just before we dismiss for the Christmas holidays, I have my students complete my activity called, "The Dichotomous Key to Holiday Giving and Community Service." (FREE download.)

The students are given the different candies and toiletries.  They must use my dichotomous classification key to determine the "scientific" name of each item.  As the candies are classified they are placed into small red stockings.  As the toiletries are classified, they are placed in quart sized ziplock bags.  After school we deliver the stockings of candy and the bags of toiletries to our local food bank.  We live in a small town so many of the students are able and willing to accompany me to the food bank.  As the food bank distributes food for the holidays, they will include our candy and toiletries in the boxes of food they distribute.  The fine folks who work at the food bank are always so excited to get our small contributions, and many of my students will stay at the food bank for the afternoon and volunteer.

I have a particular fondness for our small, local food bank, but you might also consider doing this activity and donating your items to a nursing home or another worthwhile organization such as the Salvation Army.  Your students might not learn a whole lot of science in this activity, but they will experience the joy of giving and the value of serving the community.

You can download this activity for free:  A Dichotomous Key to Holiday Giving and Community Services.    I hope you enjoy this activity as much as I do!

Have fun teaching!