Perhaps the first assay we learned in science class was the starch test, where we dropped iodine on a substance, and if it turned “blue-black”, it indicated the presence of starch.

Now, as modern-day science teachers, we carry on the wisdom of generations of science teachers, and continue to avoid calling the positive result “black and blue”, as no science teacher wants students to associate bruises with white bread or potatoes.

The starch test has become such a common test, that I believe the term “starch test” should replace “litmus test” as the analogy cliché for social or political tests. (For example, Wikipedia states, “A litmus test is a question asked of a potential candidate for high office, the answer to which would determine whether the nominating official would choose to proceed with the appointment or nomination.”) How many non-science teachers even know what litmus is or what a litmus test is? Let’s start using analogies more people can relate to. [People would really start liken that (with an intended pun on the nature of litmus)!]

Today is the six-month anniversary of this blog. It seems such a short time ago, but alas, on June 20, 2008, my first blog was posted. This made me wonder, “How does one know if one is successful after just six short months?

To find the answer to this query, I did a search on blogs. I found no numerical metrics for success. Looking at the latest report from Google Analytics, I did see that more than 35 people per day have read this blog, and that this month alone, there were over 1,000 readers from 70 countries/territories.

The search for blogs about blogs (i.e. metablogs) yielded no numbers, which I viewed once again as evidence that collective wisdom can often be found in groups of people. The qualitative metric I did derive, however, from reading the advice of more experienced blog pundits was this: If a blogger enjoys writing about their interests, and some people are reading, then it should be considered successful. As far as this starch test is concerned, I judge this blog as a success, and I thank you for reading it.

But now on to science teaching and technology, which is the focus of this blog. In the living world, photosynthesis is one of the most important processes. Fortunately, Adaptive Curriculum has a free interactive activity that teachers and students (from all 70 countries/territories) can use to learn more about photosynthesis. In “Plants Needs for Photosynthesis” students conduct several investigations, where they can add or subtract water, light, carbon dioxide, and oxygen. The plant then does its thing (AKA: metabolism) for four hours.

After this, the starch test is performed to see if photosynthesis occurred. In the starch test, the leaves are boiled and then dipped into hot alcohol to remove the green chlorophyll. Next, the leaves are dipped into room temperature water. Finally, drops of iodine are placed upon the leaves. Through these discovery-based learning experiences, students are able to determine the conditions that are needed for photosynthesis to occur.  

Thank you to Adaptive Curriculum for giving us this free Flash-based activity, and for their support of this blog. And no matter what your starch test or litmus test for happiness may be, I wish you a happy holiday season.

Resources:

If you (or your students) don’t know what a litmus test is, here are some links:

Adaptive Curriculum’s “The Properties of Acids”

Adaptive Curriculum’s “The Properties of Bases”

Adler, Kris Lesson Plan: The pH scale.