If rhubarb stem is placed in a solution of permanganate, the purple permanganate ion is reduced to the colorless Mn2+ ion. It is thought that the oxalic acid present in rhubarb causes this reduction. The investigations presented in this post provide evidence that this may not be the whole story...
Near the end of the school year we are all thinking about what we will do with our AP Chem students until the end of the semester. Last year I wrote about a post AP independent study activity that I use dealing with transition metal compounds. I still like it and use it. But this year I want to talk about a very involved lab that many of my colleagues are ignoring.
I will share how I use the Target Inquiry activity, Change You Can Believe In. I have realized that I need to include particulate models within the assessments after the lab to fully evaluate my student's conceptual understanding.
This blog post may be a bit non-traditional, but in this submission I recall a memory from early in my teaching career when my dad (who was an environmental chemist) visited my classroom. The day remains embedded in my memory bank, and had a profound impact on how I view labs - as an opportunity to extend the learning.
I tend to enjoy acid base titrations for several reasons. First, students get to work with burettes, acids, bases and they see a nice "color change" when they reach an endpoint. Many times, students who tend to struggle with pen and paper testing excel at the "hands-on" approach. Titrations also dovetail well with stoichiometry which provides a nice review of information closer to the end of the year.
When describing abstract concepts like chemical bonding, it always seems to feel far too easy for both teachers and students to resort to the “wants” and “needs” of atoms. After all, we understand what it means to want, need, or like something, so it often feels appropriate (and easier) to use a relatable metaphor or subtly anthropomorphize these atoms to accommodate our students’ current reasoning abilities. While predicting the types of bonds that will form and the general idea behind how atoms bond can be answered correctly using such relatable phrases or ideas, the elephant in the room still in remains—do our students really understand why these atoms bond?
The College Board offers the opportunity to have access to guided inquiry "Building Block" performance tasks, "Building Block" digital assessments, and FRQ-style end of "Building Block" assessments directed specifically at nine "challenge areas." The "challenge areas" are organized according to the AP Chemistry six big ideas. I have used most of the resources available in AP Insight this year with my honors and AP chemistry students. Today, post-AP exam, I asked the students to provide me with feedback about the usefulness of those resources.
I think this experiment provides a fantastic vehicle to involve students of all ages in small, hands-on and exploratory research projects. Like many others, my students and I have investigated various aspects of this interesting fountain.