The Big Picture: General Chemistry

I thought I’d start to dive into the big picture of what I implement in my classroom. I’ll start with General/Honors Chemistry, and next I’ll write about AP chemistry. I have found it really helpful to see the scope and sequence from other teachers over time, and I hope this is helpful to you.

Guiding principles in my scope and sequence: Start with a simple representations of the nanoscopic and dig deep. Hopefully, by the time we start with vital, albeit often more challenging symbolic representations (mole, stoichiometry, solutions), students have a decent foundation to build upon.

Follow this link for more specific learning goals per unit. Here is a summary of that document:

*Note: This level 2 business is what I force all honors students to do. I’m not perfect, but I try to structure my classes such that students in general chemistry who are ready for level 2 work have access to it and are assessed on it.

General Notes:

I consider myself an engineer of sorts and stand on the shoulders of those who came before me. In addition to connecting with lots of people over time, here are some commercial resources that have shaped curriculum that I will likely elaborate upon in future posts:

1. Living by Chemistry (Bedford, Freeman, and Worth) - When I purchased this in 2010, it was about $1,000 and used a mini-grant to pay for it. I’m not sure what the pricing structure is now.

   1. Pros: It’s not really the book...it’s the 5E daily activities that are overall well designed to always fit a larger purpose or theme. I have learned a TON from using this curriculum. It’s worth it. This is where I get my (seemingly random) unit titles. Also, the people who worked to develop this curriculum are well-respected chemists at UC-Berkeley, led by Dr. Angelica Stacy. This work has been field tested in many environments and it shows in the final product. Also, they are always at NSTA and are very friendly to talk to in person.

   2. Cons: Gauge your students. Oftentimes, my students need more practice in class before moving on.

2. POGIL Activities for High School Chemistry (Flinn Scientific)

   1. Pros: Activities are pretty solid, and in the teacher resources, there are some common misconceptions to look for as students work, as well as sample assessment questions. Also, it’s $52. I bought this with my own money.

   2. Cons: I have been fortunate enough to have engaged in multiple POGIL facilitator trainings, as the PO stands for Process Oriented...aka how to get kids to work together and share/challenge ideas? These activities can go downhill FAST if they are treated as daily worksheets to complete.

All in all, I have landed in this place scope and sequence-wise after seven years of inquiry and thought to develop a chemistry narrative to support students in (I think) meaningfully connecting the macro-, nano- and symbolic world.

Here’s why I’m keeping this short and sweet:

• What questions do you have? (Like, how in the world do you teach titrations before stoichiometry)?

• What is your overall scope and sequence? How did you arrive there? Post a link or upload a file?

How did someone figure that out? Can you explain to me why this happens? No matter the topic, individuals are always seeking information as they look to explain complex objects and theories. “Thing Explainer: Complicated Stuff in Simple Words” by Randall Munroe uses only one thousand of the most common words to explain various inventions and phenomena in the field of physical science.

In addition to the fundamental language of each description, Munroe also includes straightforward illustrations in a manner that any reader can comprehend. Although some may be disappointed with the lack of scientific vocabulary, I for one appreciate the theme of the book as it provides our students with various examples that do not include the jargon they assume should be used in every explanation.

Within the book Munroe describes ‘things’ that are incorporated into secondary chemistry curriculum such as nuclear reactors, microwaves, and the sun. Other ‘things’ described by Munroe in which our students may already have prior knowledge of, such as the periodic table and the electromagnetic spectrum, can be evaluated in a class discussion as they critique the author’s description and imagery.

  “Thing Explainer:” is an entertaining book for those who are curious about how the objects surrounding them function. If you would like to know more about another publication by Randall Munroe, consider reading Hal Harris’s blog entry “What If? Serious Scientific Answers to Absurd Hypothetical Questions". 

It was a familiar childhood sound. You know that sound? A bin of Lego building blocks. You want that one particular piece. You rake through the pieces with both hands, searching. That noise. It was often heard during my younger years and now filters down from my children’s bedrooms upstairs. But, as someone connected with teaching and learning chemistry, I don’t have to leave that toy (or sound) behind.

Building Chemistry I

Building blocks have been part of multiple past Journal of Chemical Education articles. Two examples immediately come to mind. We used it in the JCE Classroom Activity Putting It All Together: Lab Reports and Legos nearly 15 years ago,  to make the point that you should record observations as you make them rather than trusting them to memory and to illustrate the writing needed for lab reports. More recently, fellow XChange contributor Tom Kuntzleman used it for a visually delightful group Lego Periodic Table project, described in Constructing an Annotated Periodic Table Created with Interlocking Building Blocks: A National Chemistry Week Outreach Activity for All Ages. (Both articles available to JCE subscribers.)

The June 2016 issue of JCE adds another to the collection: Interlocking Toy Building Blocks as Hands-On Learning Modules for Blind and Visually Impaired Chemistry Students. (freely available to all as an ACS AuthorChoice article). The authors use the blocks to show trends in periodic table properties, such as relative atomic and cationic radii, ionization energies, and electronegativities. However, their use is more than that, providing a tactile experience for blind and visually impaired students to experience and learn about the trends by touching the models and their Braille labels. The remarks from surveyed students were positive. They included: “Touching the periodic table gives better perception,” “They are easier to grasp and faster to comprehend than Braille periodic table,” and “Building blocks help me pick trends quickly.” The authors even tested it with blindfolded sighted students.

The models can also be used as a visual way to cement periodic table trends with sighted students. The authors used them in a large class using a document camera to display the models. In smaller classes, perhaps students could visit stations with pre-built models to make observations and answer questions related to the trends, or maybe construct the models themselves. Directions for construction are not included with the article, although with some work they could probably be ascertained from studying the multiple color figures. I emailed the corresponding author while writing this article to ask if they are available elsewhere; he confirms there are no other specific instructions to build the modules and that they can be built as shown in the figures (email communication with R.B. Dabke, 2016 Jun 12 and 2016 Jun 14). 

The authors recommend purchasing building block kits and baseplates in local stores’ toy sections, but I also suggest you see if there’s a Bricks & Minifigs store near you. Not all U.S. states have locations, but they’re a less expensive way to get Lego bricks and other pieces. There are bulk bins to rummage through to find what you need. You choose a container size and pay a set price for whatever pieces fit into the container.

Building Chemistry II

This issue also had an article with another model building material that looked interesting, described as “plastic nested balls” and “plastic Christmas balls.” From the figures in the article, the balls appear to be a product similar to these acrylic fillable ball ornaments, which are available in different sizes, so they can nest inside each other. The authors of Big Atoms for Small Children: Building Atomic Models from Common Materials To Better Visualize and Conceptualize Atomic Structure (available to JCE subscribers) use them to add a concrete item for elementary-aged students to use when discussing the atom. The balls function to create a 3-D model of an atom, so that a clay nucleus can have a place in the center of a spherical construction and small round pasta or beads can be located outside the nucleus as electrons. Although a simple model to put together, it has a lot of information packed into it. The authors list 11 different points about atoms that it helps to show.

The activity could also be reversed—students could be shown one of the models and answer questions about how it illustrates points that they’ve learned about atoms. For example, where are the protons and neutrons located? How does the number of pasta electrons compare with the number of green protons in the nucleus? Where is the main mass of the atom? They could then construct their own model for an atom of a different element.

The authors summarize the experience of their model, and I think, the Lego models described above: “A knowledge built ‘with one’s own hands’ that works together and cooperates with one’s mind is the basis for the construction of a deep and long-lasting learning.”

Look for Mary Saecker’s post JCE 93.06 June 2016 Issue Highlights for more content from this issue.

It's been a few days since my summer break began. I have had a few days to decompress, relax, and think about my next post. I have been planning to write about concept mapping since the end of our first semester. I first recognized the effects of concept mapping in the classroom when I read Shannon Bowen's blog post last December.

When I read Shannon's post and commented, she mentioned that students' test scores increased as well as their understanding and comprehension of content. I was excited to try this approach to final exam review. So, last semester I conducted an experiment with my 4th hour Honors class as the control (standard packet review) and my 6th hour Honors as the test subject (concept mapping). My 6th hour class was divided into groups and were given 4 days and a 6' x 3' sheet of white paper. In the end, my 6th hour class demonstrated greater understanding and questioning abilities of the content they had covered; they scored 5% higher on the multiple choice portion and 10% higher on the written portion. This was enough to convince me to have all of my freshman chemistry classes concept map their review the next semester but with a slight caveat. In addition to doing a group concept map on paper (over 2 days), students took advantage of my Chromebook cart (courtesy of the blended learning pilot I participated in this past year) and developed individual digital concept maps using either Lucidchart Diagrams or Google Drawing. The goal with this approach was that students developed a pretty significant piece of work collaboratively and then further studied and became familiar with the content as they developed their own work. Below are some examples of analog and digital concept maps.

concept_map_1.jpeg

concept_map_3.jpeg

concept_map_4.jpeg

flowchart_-_new_page.jpeg

Upon conclusion of this most recent semester, I found mixed results. One of my honors classes saw a 4% jump in multiple choice and a 9% rise in the written portion (as compared to the fall semester's control group). My other honors class saw a 1% decrease in multiple choice and 1% increase in the written portion (seemingly negligile results). When comparing this semester's regular chemistry classes to last semester, the data shows a concerning decrease in scores.

What can the drop in scores in regular chemistry be attributed to? A number of factors cross my mind but some of my observations include a lack of motivation to actively work in a group or contribute to the review process. Many of the students were not accustomed to thinking and working proactively on projects like this. Some students really struggled with connecting the dots so-to-speak between various concepts. My pre-intern and I did our best to guide students through the process of creating a concept map and questioning students who said they were "done." These student groups quickly realized they were far from being finished and consequently may have struggled with motivation to continue and also find value in doing this type of review. Others were absent during the review period.

Nonetheless I still recognize value in this type of exam review and plan to continue working with it in future semesters. For what it's worth, a biology teacher in my department has begun incorporating more concept mapping into his unit reviews after watching my classes work through it at final exam time.

Visualizations for Chemistry Teaching and Learning

The June 2016 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: visualizations for chemistry teaching and learning, periodic table resources for teaching visually impaired students, biochemistry in the classroom and laboratory, spectroscopy in the laboratory, commentaries on analytical chemistry topics, resources for teaching, distilling the archives: guided-inquiry experiments.

Editorial

In the Editorial Communicating Chemistry in Informal Environments: A Framework for Chemists, Mary M. Kirchhoff of the Education Division of the ACS discusses a recent report by the National Academies, Effective Chemistry Communication in Informal Environments. This freely available resource offers a framework to guide and encourage chemists in engaging successfully with the public.

Visualizations for Chemistry Teaching and Learning

Visualizing Molecular Chirality: Cover Feature

The cholesteric liquid crystal phase is a fluid in which rod-like molecules are orientationally ordered, with an overall helical twist. Such phases can be induced by adding a chiral solute to an (achiral) nematic liquid crystal. With sufficiently powerful chiral dopants, the pitch of the twist is on the order of the wavelength of visible light, and the phase will selectively reflect circularly polarized light. This property allows for a straightforward macroscopic visualization of molecular chirality. In Visualizing Molecular Chirality in the Organic Chemistry Laboratory Using Cholesteric Liquid Crystals, Maia Popova, Stacey Lowery Bretz, and C. Scott Hartley describe a simple experiment in which students synthesize a single enantiomer of a chiral dopant and then dissolve it in a commercially available liquid crystal host. A film on a glass slide allows students to deduce the absolute configuration of their starting material by observing the reflection of light through the filters in disposable glasses for 3D video.

Visualization Using Models

Promoting Representational Competence with Molecular Models in Organic Chemistry ~ Andrew T. Stull, Morgan Gainer, Shamin Padalkar, and Mary Hegarty

Effectiveness of Inquiry-Based Lessons Using Particulate Level Models To Develop High School Students’ Understanding of Conceptual Stoichiometry ~ Stephanie Kimberlin and Ellen Yezierski

Big Atoms for Small Children: Building Atomic Models from Common Materials To Better Visualize and Conceptualize Atomic Structure ~ Laura Cipolla and Lia A. Ferrari

A Cost-Effective Physical Modeling Exercise To Develop Students’ Understanding of Covalent Bonding ~ Kristy L. Turner

Better Understanding Using Visualizations

Insights into How Students Learn the Difference between a Weak Acid and a Strong Acid from Cartoon Tutorials Employing Visualizations ~ Resa M. Kelly and Sevil Akaygun

Visualizing, Rather than Deriving, Russell–Saunders Terms: A Classroom Activity with Quantum Numbers ~ Paolo Coppo

Using Visualization To Teach Symmetry

Helping Students Understand the Role of Symmetry in Chemistry Using the Particle-in-a-Box Model ~ Meghna A. Manae and Anirban Hazra

Discovering Symmetry in Everyday Environments: A Creative Approach to Teaching Symmetry and Point Groups ~ Kei Fuchigami, Matthew Schrandt, and Gary L. Miessler

ConfChem Conference on Interactive Visualizations

ConfChem online conferences are free, open to the public, and run by the ACS DivCHED Committee on Computers in Chemical Education (CCCE). The spring 2015 ConfChem conference discussed Interactive Visualizations for Chemistry Teaching and Learning.

ConfChem Conference on Interactive Visualizations for Chemistry Teaching and Learning: An Introduction ~ Robert Belford and Emily B. Moore

Insights into Molecular Visualization Design ~ Resa M. Kelly

Learning by Being—Playing Particles in the MeParticle–WeMatter Simulation ~ Elon Langbeheim and Sharona T. Levy

A Multimodal Examination of Visual Problem Solving ~ Sarah J. R. Hansen, Felicia M. Mensah, and Peter Gordon

Using an Interactive Simulation To Support Development of Expert Practices for Balancing Chemical Equations ~ Yuen-ying Carpenter, Emily B. Moore, and Katherine K. Perkins

Research into Practice—Visualizing the Molecular World for a Deep Understanding of Chemistry ~ Roy Tasker

The Cutting Edge—Educational Innovation, Disability Law, and Civil Rights ~ Emily B. Moore and Paul D. Grossman

Concerns Regarding Accessible Interfaces for Students Who Are Blind or Have Low Vision ~ Cary A. Supalo

Accessibility for PhET Interactive Simulations—Progress, Challenges, and Potential ~ Emily B. Moore

Periodic Table Resources for Teaching Visually Impaired Students

Evaluation of Existing and New Periodic Tables of the Elements for the Chemistry Education of Blind Students ~ Dennis Fantin, Marc Sutton, Lena J. Daumann, and Kael F. Fischer

Interlocking Toy Building Blocks as Hands-On Learning Modules for Blind and Visually Impaired Chemistry Students ~ Samuel Melaku, James O. Schreck, Kameron Griffin, and Rajeev B. Dabke

Biochemistry in the Classroom and Lab

Chemical Education ResearchImplementing an Active Learning Environment To Influence Students’ Motivation in Biochemistry ~ Camila Aparecida Tolentino Cicuto and Bayardo Baptista Torres

Team-Based Learning, Faculty Research, and Grant Writing Bring Significant Learning Experiences to an Undergraduate Biochemistry Laboratory Course ~ Hedeel Guy Evans, Deborah L. Heyl, and Peggy Liggit

Student-Led Development of an Interactive and Free Biochemical Methods eBook ~ Alyssa C. Hill, Logan M. Nickels, and Paul A. Sims

Laboratories

Searching for Synthetic Antimicrobial Peptides: An Experiment for Organic Chemistry Students ~ Thomas E. Vasquez Jr., Cristina Saldaña, Katy A. Muzikar, Debra Mashek, and Jane M. Liu

Purification and Electrophoretic Characterization of Lactate Dehydrogenase from Mammalian Blood: A Different Twist on a Classic Experiment ~ Linda S. Brunauer

Spectroscopy in the Laboratory

Gold(III)-Catalyzed Hydration of Phenylacetylene ~ J. Michelle Leslie and Benjamin A. Tzeel

Preparation of a Cobalt(II) Cage: An Undergraduate Laboratory Experiment That Produces a ParaSHIFT Agent for Magnetic Resonance Spectroscopy ~ Patrick J. Burns, Pavel B. Tsitovich, and Janet R. Morrow

Synthesis and Characterization of a Perovskite Barium Zirconate (BaZrO₃): An Experiment for an Advanced Inorganic Chemistry Laboratory ~ Todsapon Thananatthanachon

Determining the Energetics of the Hydrogen Bond through FTIR: A Hands-On Physical Chemistry Lab Experiment ~ Abby C. Guerin, Kristi Riley, Kresimir Rupnik, and Daniel G. Kuroda

Determining the Structure of Oxalate Anion Using Infrared and Raman Spectroscopy Coupled with Gaussian Calculations ~ Karen I. Peterson and David P. Pullman

Commentaries on Analytical Chemistry Topics

Clarifying Misconceptions about Mass and Concentration Sensitivity ~ Pawel L. Urban

My Dear Buret, Your Time Has Indeed Come! ~ Jonathan E. Thompson and Ly Brode

Resources for Teaching

Harnessing a Mobile Social Media App To Reinforce Course Content ~ Andrew L. Korich

ChemBrows: An Open-Source Application Software To Keep Up to Date with the Current Literature ~ Jean-Patrick Francoia and Laurent Vial

Using Least Squares To Solve Systems of Equations ~ Joel Tellinghuisen

Review of The Lost Elements: The Periodic Table’s Shadow Side ~ Jeffrey Kovac

Review of Early Responses to the Periodic System ~ Robert E. Buntrock

Review of ChemConnections Activity Workbook ~ Shannon Andrews

Distilling the Archives: Guided-Inquiry Experiments

In this issue, Nimesh Mistry, Christopher Fitzpatrick, and Stephen Gorman describe a laboratory in which students Design Your Own Workup: A Guided-Inquiry Experiment for Introductory Organic Laboratory Courses. Some guided-inquiry experiments from past issues include:

The Dynamic Density Bottle: A Make-and-Take, Guided Inquiry Activity on Density ~ Thomas S. Kuntzleman

Filling a Plastic Bag with Carbon Dioxide: A Student-Designed Guided-Inquiry Lab for Advanced Placement and College Chemistry Courses ~ Laura M. Lanni

A Guided Inquiry Liquid/Liquid Extractions Laboratory for Introductory Organic Chemistry ~ Margaret L. Raydo, Megan S. Church, Zane W. Taylor, Christopher E. Taylor, and Amy M. Danowitz

Like Dissolves Like: A Guided Inquiry Experiment for Organic Chemistry ~ Ingrid Montes, Chunqiu Lai, and David Sanabria

An Interdisciplinary Guided Inquiry Laboratory for First Year Undergraduate Forensic Science Students ~ Sarah L. Cresswell and Wendy A. Loughlin

Visualizing a Great Resource: JCE

With 93 volumes of the Journal of Chemical Education to see and experience, you will always find something informative—including the articles mentioned above, and many more, in the Journal of Chemical Education. Articles that are edited and published online ahead of print (ASAP—As Soon As Publishable) are also available.

Summer is here! Please consider submitting a contribution to the Journal of Chemical Education. Erica Jacobsen’s Commentary gives great advice on writing for the Journal. In addition, numerous author resources are available on JCE’s ACS Web site, including: Author Guidelines, Document Templates, and Reference Guidelines. The Journal has recently issued a call for papers on Polymer Concepts across the Curriculum, so consider submitting a contribution to our next special issue.

On June 20, 2016 at 6:34 P.M. E.S.T., our sun achieves the most northern point in its journey and stops. The summer solstice marks the moment when the sun stands still; a Latin derivative from the words sol, meaning ”sun”, and sistere, meaning “to come to a stop.” Imagine the wonder and curiosity associated with such a phenomenon in the ancient world! For many observing solar movement, time literally stood still. Ancient Chinese celebrated the yin, or femininity, on the June solstice. Ancient Egyptians believed the solstice signaled the coming of the annual flooding of the Nile River, which nourished their fields. Modern celebrations continue across the globe. This year, my soon-to-be chemistry students are celebrating on Schoology as they complete their summer assignments. You’re welcome, kiddos!

Last month, I explained my chemistry team’s plan to implement our first pre-course assignments for next year’s students. Thank you for your feedback! Our team read each of your comments, and we discussed your experiences and questions. We developed the courses in Schoology basically as described in my May blog post. You can view the students' checklist attached to this article. The students see the following four courses when they log in, and they find four to six assignment folders inside the appropriate course.

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While enjoying family time, I am loosely following the students’ progress in the three courses that I'll be teaching next year. Here are my most recent data points and observations:

DATA:

• 41 students have joined the Preparing for Chemistry 2016-2017 course on Schoology.

• 21 students have spent 20 minutes or more working in the course during the first two weeks of summer.

• On-level chemistry course data: 

  • Two students have completed the Metric System Review assignment and online quiz.

  • The average score is 80%.

  • No on-level students have completed the next assignment.

• Honors chemistry course data: 

  • Four students have completed the Metric System Review assignment and online quiz. The average score is 85%.

  • Two students have completed the Density Review assignment and online quiz. The average score is 100%.

  • Two students have completed the Dimensional Analysis assignment and online quiz. The average score is 88%.

• Year-long Honors and AP Combination chemistry course data:

  • Seven students have completed the Metric System Review assignment and online quiz. The average score is 91%.

  • Three students have completed the Density Review assignment and online quiz. The average score is 87%.

  • Three students have completed the Dimensional Analysis assignment and online quiz. The average score is 100%.

• Schoology Analytics data: 

  • Students have most commonly spent between 25 and 90 minutes working in the course thus far. 

  • Seven students have invested more than one hour of time.

  • Many students are accessing the "extra help" links, particularly simplifying expressions in algebra.

OBSERVATIONS:

1. The number of students currently enrolled is extremely low. The number should be five or six times higher.

2. One of the honors chemistry students ran out of time answering a dimensional analysis question in the online quiz. Will the three-minute time limit need to be increased? 

3. Two of the hyper-accelerated, honors/AP combination chemistry students made simple algebra mistakes when solving for mass and/or volume in the density online quiz.  Will this be a theme? How and when should I respond? Algebra is often an unexpected weakness in our hyper-accelerated math students. 

4. Schoology allows teachers to distribute "badges" to encourage and recognize student performance. I created and distributed a badge to each of the students who has spent over an hour in the course. I'm proud of their motivation. What can I do to encourage more? I'm only interested in positive reinforcement. 

I'm deeply interested in your wisdom and advice! Please leave a comment or idea. I'm also happy to share more details of our assignments if you have been encouraged to develop something for your students. Happy Summer! 

I published an article about an independent study unit I use with my AP Chemistry class two years ago, A guided group inquiry lesson on coordination compounds and complex ions. In the time since it was published, I have expanded the unit quite a bit and written some new assignments to go along with it. I use this unit every year as a post AP activity and am very fond of it. I thought some of my readers might enjoy seeing how it has changed and get access to the new assignments I have developed for it.

I like having a great amount of flexibility with this unit. All of us who teach AP understand that being the first exam of the two week program, we are then faced with nine days of rotating absences on the part of our students. Some days we have no kids in class, maybe one, and maybe all of them. So I set this assignment up and then let them work at their own pace. I have lots of very good one on one discussions with the kids when they are ready. I encourage them to form groups of four students each to work on it and then allow quite a bit flexibility depending on who is actually in the room on any given day.

My new schedule runs for ten days instead of six. I now have four assignments that I have written that are part of it. The first is a vocabulary assignment that is a hybrid of old and new terms for the students. It starts off with a discussion of terms they should remember from the course and uses them to help bridge into the new material.

vocabulary.pdf

vocabulary.pdf

The second assignment is a nomenclature exercise for complex ions and coordination compounds. I have taken an interesting turn with it and made the first question to actually list the rules for naming these species.

nomenclature.pdf

nomenclature.pdf

The third assignment deals with the structure of complexes, coordination compounds, and their isomers. It is self guided and worked very well this year.

isomers.pdf

isomers.pdf

The fourth is a challenging assignment dealing with the formation and reactions of complexes. It is modeled very much after former AP Chemistry questions and Chemistry Olympiad semifinal exam questions that deal with complexes. I found this to be very enjoyable for one on one discussions with the students.

reactions.pdf

reactions.pdf

For the two experiments, you can find one that I previously posted Complex Ions Lab,  and the second is called “The Chemistry of Complex Ions” and you can purchase this as a kit from Flinn. 

Note: If considering using this lesson, I recommend reading my original article on the topic for background information. 

Supporting Information:

A Bonding Theory/ The Werner-Jorgensen Controversy, A Review of a two part simulation published in the Journal of Chemical Education November,1993.

Werner and Jørgensen Bond Theory Software Simulation - Requires a ChemEd X subscription, but will be freely available for readers through May 31, 2017.

The Evolution of Bond Theory-Requires a ChemEd X subscription, but will be freely available for readers through May 31, 2017.

    In the June 6^th, 2016 Chemical and Engineering News magazine put out by the American Chemical Society, C&EN talks with Deborah Blum, journalist and author: From the article’s description, ‘The Poisoner’s Handbook’ writer talks about the beauty of chemistry and why she wants people to know more about it.

     If your unfamiliar with the book“The Poisoners Handbook: Murder and the Birth of Forensic Medicine in Jazz Age New York” or the video  “American Experience: The Poisoner’s Handbook", then I suggest you check out the links provided. I haven’t read the book but I have used the video in my high school classroom. I shared clips of the video with my students and it served as a great introduction into many chemical topics such as how chemistry began playing such an important role in forensics.  The video explores the pioneering work of Charles Norris, a medical examiner and Alexander Getler, a toxicologist and the importance of their work during such a unique time in American history.  If you’re a history fan, or a forensic science fan, or you want to share with your students the fascinating chemistry associated with this then I recommend you check it out.

      If you’re an amazon Prime member, then the video is free to watch using the link above, if you are not then I was able to find it on YouTube.  If your school blocks youtube then in the app store you can download the app PBS video.   With this app you can watch many shows from PBS including if you search for Poisoner’s Handbook it will pop up for you to watch.  Here is a link to the movie’s transcript.  Next here is a link for video questions and even experiments that you can set up yourself to simulate what was done in the video.  I hope your students enjoy as much as mine.  

What do you do when you don’t have any local or affordable opportunities for professional development? 

This is the situation I found myself in this summer when I started looking for local professional development on Standards-Based Assessment and Reporting (SBAR, sometimes called SBG or SBL). This past year I began the paradigm shift to a standards-based assessment model. I had been contemplating the change for several years when I attended a workshop by Rick Wormeli and resigned myself to making serious changes in my assessment practice. I was lucky to have a friend (and fellow chemistry teacher), Jeremy Horner, who is six years into using the model. He was a tremendous resource throughout the year, and would help me troubleshoot when challenges arose.

In February, I participated in a presentation on SBAL at our local science teacher’s conference. We had a good turnout and great conversations with teachers at all stages of implementing the model in their classrooms. As school was wrapping up I began looking for local opportunities for continued professional development on SBAL, but came up empty handed. There were meetings and workshops being held in other parts of the country, but in addition to the cost associated with travel, they came with a hefty registration fee.

One afternoon as we were discussing assessment practice (yes, I really do this) and the lack of conferences in our area Jeremy asked, “Why don’t we organize a conference?”

Yeah.  I should have thought of that.

That day we recruited Hugh Ross as our third facilitator and started planning and collecting resources. A month later we hosted the first (free!) Central Indiana Standards Based Learning Summit.

Our vision for this meeting was to provide a platform for local teachers to get together and reflect on their grading practices, share resources, and build a community of teachers who could support each other. We had no funding so we couldn’t pay teachers for their time, but we were offering the summit at no cost to anyone. I hoped to attract around ten teachers willing to share the day with us.   

I posted the information on a few groups on Facebook and on Twitter. There was a lot of interest and inquiries and in the end I had fifteen teachers register.  I was excited and little scared – I’ve hosted plenty of workshops before, but nothing like this. We also had two teachers coming from out of state to join us.  These teachers were giving up hours of their time to drive to central Indiana and staying in a hotel for a night, just to meet and talk about ways to improve student learning in their classrooms. I was really feeling the pressure to deliver something everyone would find useful and worthwhile. 

The day of the meeting ten teachers arrived from all different school districts and from a variety of disciplines. We spent the morning discussing ideal classrooms and thinking about how we would modify our current grading policies if we didn’t have any outside restrictions. We pulled readings from books and articles to help frame the discussions. We all reflected on why we have grades in the first place. We shared in small groups, and reported out to the larger group. We talked about how to give useful feedback and how to help students learn from the feedback we provided. 

In the afternoon we shared how we wrote learning objectives, how we handled reassessments, how we tracked progress, and how we calculated overall grades. We evaluated several types of rubrics and grade calculation methods. We shared our frustrations with current practice and we celebrated our victories. The teachers with the most experience offered advice and examples to those of us just starting out. 

At the end of the day, we compiled a shared folder with all the examples and resources from the day to be shared with everyone who attended. Most importantly, everyone walked away with contact information of the other teachers from the meeting. We all had great new resources to help us on our way to implementing (or improving) SBAL in our classes. 

While I could have framed this blog post as an article about SBAR or SBG (we have some great posts on this by the way) what I really wanted to share with everyone is the idea that you can create your own professional development. If there’s an idea you’re passionate about – go out and find others who share that passion. We have a tremendous number of social media resources where you can meet and collaborate with each other. Many schools don’t have the funds to help teachers with registration fees or travel expenses, but don’t let this deter you from seeking out ways to improve your classroom practices.  Check Facebook groups, twitter hashtags, organizations such as AACT, ACS, NSTA and their local affiliates – all of these places can be a place promote your idea and invite others to join you. You can even write a short article for ChemEdX and we'll post it to our site and promote it on twitter and facebook!

Sometimes, instead of waiting for opportunities, we have to create them.

For teachers interested in SBAL I suggest following Megan Moran and Aric Foster on twitter for great resources and inspiration. If you want to learn more about our summit, please leave a comment below and I can link you to the readings we provided.  

               Throughout the last ten years teaching both chemistry and Advanced Placement Chemistry I have realized that the concept of equilibrium does not receive enough attention in my first-year chemistry course. Sure, the concept of equilibrium is a topic mentioned and identified throughout the course however the dialogue in regards to conditions that would shift the chemical system is minimal at best.

                In the past, I have used simulations involving objects, such as coins or paper clips, to determine equilibrium constants however I have to wonder if the students really understood the big idea these manipulatives were supposed to represent. In addition I find that most students can define Le Châtelier's principle however struggle when asked to explain why shifts in the chemical system occur.

                In addition I have noticed that students have misconceptions about reactions before they arrive in first-year chemistry courses. For many, they developed the misconception that once something experiences a chemical change then the reaction is ‘complete’. In fact I have heard numerous students refer to all reactions as irreversible.

                As I reflect on both my own curriculum as well as student misconceptions it is obvious that I need to include more evidence on how conditions of a chemical system can change and therefore cause a shift in equilibrium. Although this is a concept that is regularly addressed in an AP class, how is it meaningfully incorporated into a secondary chemistry classroom?

                With many states recently adopting the Next Generation Science Standards, many teachers may have to redesign their curriculum as the standards place an emphasis on rates and equilibrium. In fact, two of the eight standards regarding matter and its interactions involve student comprehension of reaction rates and equilibrium. Although students are not required to calculate any equilibrium constants and/or concentrations they do have to recognize and explain the outcome of changing a chemical system.

                Despite whether or not your state has adopted NGSS, my question that I would like to build a dialogue around is: What do you do in your class to introduce and develop the concept of equilibrium?

                Please feel free to comment below and provide any student feedback, if available. 

This popped up on my Facebook feed the other day:

To be 100% transparent, I was planning to write this post. In light of seeing requests like this on the interwebs, I hope this personal reflection gives ideas and provides activation energy to begin on a gratifying, yet kind of daunting, task.

In my last post, I discussed my first year chemistry scope and sequence. Here, I continue with AP chemistry scope and sequence, and a little bit with how I developed it the year before, the summer before, and during the year. Keep in mind, I consider the work I do with students to always be a project in progress. I learn so much from working with them as they engage with the content through a different perspective than I have.

January-ish 2014: The School Year Before

Teaching at a charter school in its third year, my department chair came to me and asked for a list of supplies that needed to be purchased. I had never taught AP chemistry, and had no clue. While I wasn’t committing yet to Flinn’s lab kits, I did use them as a guide to determine glassware and instrumentation required for the course. (Side note- while I did order the Flinn kits for year one, I ended up gutting many of the kits to use different write ups).

June-July 2014: The Summer Before Teaching

So when did curriculum planning begin? First, I attended an APSI (AP Summer Institute) at the University of Tulsa. I was still intimidated by content I hadn’t seen in some time, even though by degree is in chemistry. I figured why make myself crazy in advance? After that experience, I dug into the standards. I found the PDF from the college board really unuseable. I found a spreadsheet of standards from the depths of the AP Chemistry Discussion board. After reviewing big ideas and sample scope and sequences from the College Board/people on the internet, here is where I landed:

To me, integral themes in the story of chemistry are “What do I have? How do I know?” Since spectroscopic techniques are used throughout the year, I just figured I had to start there.

Also, with this scope and sequence, virtually every topic was visited TWICE (yay spiraling content!). For instance, my students learned about voltaic cells, balancing redox reactions, calculating cell potential in Unit 3. They then see it again in Unit 8 second semester, when they have more thermodynamic tools available.

After this, I scoured for resources I already had in my possession, in addition to resources from the College Board - specifically, sample units from exemplar teachers. I just copied and pasted resources and essential questions into tabs in my organization hub - One Note. These scavenger hunts are fun to me, and it’s an excuse to play with a lot of new sims and encounter a lot of new ideas. Bonus: as I played with sims and scanned through activities, I totally (a) relearned and/or (b) deepened some of my content knowledge in advance. Granted, I learned a TON more when I actually started teaching it and my students engaged in the activities, but still. Every bit counts!

With this in hand, I felt my anxiety level shoot way down. A backbone to work with helped me select tasks for students. While timing didn’t go 100% as planned, we still finished content two weeks before so we could shut down and review.

August 2014 - May 2015: During the School Year

I also made friends who had taught AP Chemistry. The College Board Discussion board was just too intimidating, disorganized, etc. for me. While I was alone at my school, I had friends from the Knowles Science Teaching Foundation (KSTF). Our contexts were quite different:

• location (me in Colorado, one in Michigan, the other in Massachusetts),

• student demographics,

• personal choice in scope and sequence, and

• years of teaching,

these two people were lifesavers in so many ways throughout the year in terms of assessments, labs, and lab rubrics. Lab rubrics were the bane of my existence - easy to find labs, tough to find rubrics. As many of you may know, AP labs tend to get pretty complex pretty quickly and can take forever to grade. Having templates from friends to edit helped reign me in throughout the year. Oh, and it goes without saying they were lifesavers as I asked content questions too. I applaud the new AP Chemistry standards and assessments - they go deep. I needed help, and this was a safe space to get that help flying solo in my school and not brave enough to ask the general twitterverse.

This post is really about planning, right? Well, as overwhelmed as I was with the content choices, pacing, labs, assessments, grading, and (according to my students) collecting tears of my AP students, etc., I didn’t think about how my students would interact with the fast pace.

I am so grateful that a KSTF collaborator showed me one way she and her colleagues helped students navigate between the big picture and nitty gritty day to day. The first day of each unit students received a packet of content- guided notes, lab, practice sets. The first page of the packet had a general calendar, big ideas, and assignments with due dates. I absolutely could not commit to having everything ready by the beginning of a unit (and to this day I can’t do that), but I could tweak the idea for my context to share daily agendas with students.

The planning I did was in a giant google doc for each unit. My own personal reflections and scratch work for each unit went in One Note (look at the titles of the other tabs in the picture above), but daily tasks went in the google doc (screenshot of the first page below). My type A students LOVED the transparency in this document that our learning management system couldn’t quite capture. I felt like a wiki couldn’t quite capture the living nature of what I was creating, and formatting in wikis can just be awful. All assignments and such went in our learning management system but it all was based on the unit syllabus.

Throughout the year, I would plan about a week at a time on Sunday afternoons. Another tasset bonus here: Students also got to see the document grow throughout the unit and, I like to think, saw a tiny perspective of me as their teacher engage in this creative process and some of the agony that ensues. Often, I’d leave comments and notes to my future self on activities or assignments if things weren’t totally fleshed. Of course, students saw that too (and would sometimes leave comments in the document). Below is a screenshot from the entire document linked here.

Penultimate Thoughts

While preparing to teach a new course, even though AP Chemistry has been around for a very long time, was super gratifying. This work helped me continue to make tweaks to my first year chemistry course as well to start to develop one (relatively) cohesive story over the course of years.

Ultimate Thoughts

I learn so much from others, and am interested in your scope and sequence? How have you backwards planned for new courses?

Thank you SO MUCH for reading! On a side note, I am floored by the number of reads I get on each post. Thanks for reading, and thanks for engaging in the conversation at ChemEdX.

Chemical Mystery #7: Curious Cans

Q: Does an unopened can of soda pop float or sink in water?

A: It depends!

There are several factors involved in determining whether an unopened can of soda pop will float or sink: For example, what volume of gas is sealed in the headspace of the can? How much aluminum was used in making the can? How much soda is contained in the can? What is the composition of the beverage in the can? It is interesting that given all of these factors, almost all unopened cans of soda pop have densities very close to that of water: some a little bit higher, and others a little bit lower.¹ Of course unopened cans with densities higher than water will sink, while unopened cans with densities lower than water will float.

Several people are familiar with the classic experiment in which unopened cans of regular and diet soda pop are placed in water. When doing this experiment it is observed that diet sodas tend to float, whereas sugared sodas tend to sink. These observations can be explained on the basis of the amount of material dissolved in each type of soda. The addition of solute material to water tends to increase the density of the resulting solution. Inspection of the nutritional information on any sugared soda shows that these sodas tend to contain around 10% sugar by mass. On the other hand, only miniscule amounts of sweetener are added to diet sodas (less than 0.1% by mass)². Thus sugared sodas have higher densities than water and tend to sink while diet sodas have densities lower than water and tend to float. These observations are consistent with a paper which reported experimentally measured densities of unopened cans of soda:¹ regular sodas had densities higher and diet sodas had densities lower than 1.0 g mL^-1.  

While performing this classic experiment recently, I noticed some unexpected behavior. I won’t give away all the details just yet, because I’d like to share this unexpected result with you in Chemical Mystery #7: Curious Cans. Check out the video below, and see if you can solve the mystery of the curious cans! Be sure to share in the comments if you think you know what is going on.

References:

1. http://pubs.acs.org/doi/pdf/10.1021/ed086p209
2.  http://static.diabetesselfmanagement.com/pdfs/DSM0310_012.pdf

While I was teaching Introductory Chemistry years ago, the World News reported that the pretty actress Gwyneth Paltrow had shown up at a New York film premiere with odd circular hickeys on her shoulders and back.  It turned out that these were due to her use of an acupuncture technique known as “cupping” in which glass jars are warmed (with a candle, I think) and then placed on the skin.  As the air in the jar cools, it produces a partial vacuum.  This supposedly sucks “toxins” out through the skin.  My students and I had a good laugh at her expense – I probably should have turned it into a lab exercise. The Daily Mail photographed the same marks on Justin Bieber at the beach last year, and Jennifer Aniston, Victoria Beckham, Jessica Simpson, and David Arquette have endorsed the practice.

Over the years since then, I have seen Ms. Paltrow in many television interviews, and she nearly always has some diet or beauty tip to flog, along with her own most recent movie or tv role. Her recommendations are quite ridiculous and they are always given the utmost respect by the interviewer.  Of course, Ms. Paltrow is not the only celebrity trading on fame to promote highly questionable science. In political years like this, famous people also trade as much as possible on their celebrity to push political causes and candidates.  In “Is Gwyneth Paltrow Wrong About Everything?”, Timothy Caulfield investigates some of the claims by Paltrow and others about cosmetics, nutrition, and health. He even tries them out himself, enduring the 21-day “Clean cleanse” recommended by Paltrow, except for the daily coffee enemas part.  (You can buy the necessary vitamins and supplements for your own campaign for only $425.)

Caulfield also enjoyed a very pleasant spa facial ($250) that produced no objective change in skin appearance. He then tried a regimen in which he conscientiously treated his skin twice daily for three months with high-end cosmetic products – a cleansing-exfoliation gel, a second cleansing lotion to control bacteria, a morning moisturizer and sunblock, and an evening moisturizer especially for problem pores. Evaluation was done with the same “sophisticated” photography-based machine, before the regimen began by one expert, and afterward by another.  No objective difference. Shock!

One could argue that people who believe the celebrities and buy the products they hype are merely wasting their money.  But those products are not always benign, and there is absolutely zero oversight of nutritional claims or beauty products by the US government, so substantial harm is a real possibility.  Further, those same supposed experts on beauty engage in practices that are objectively dangerous – for example, smoking (images of Ms. Paltrow, Sandra Bullock, Katie Holmes, Julia Roberts, Jessica Alba, Ben Affleck, Ellen DeGeneres, Kate Beckinsale, Mila Kunis, Uma Thurman, Jennifer Anniston, Sean Penn with cigarettes or cigars can easily be found). Ms. Paltrow also advocates tanning: “We’re human beings and the sun is the sun - how can it be bad for you? … I don’t think anything that is natural can be bad for you”. Apparently she has not heard about hemlock, rattlesnakes, earthquakes, tornados and hurricanes, drowning, or asteroids (see my review of Naturally Dangerous, by James Collman, J. Chem. Educ., 2002, 79 (1), p 35).

“Is Gwyneth Paltrow Wrong” is written in a snarky style that its subject deserves.  I enjoyed reading it – at least, at least up to Chapter 6, which shifts to the industry that feeds on the illusion that “you too” can be a celebrity.  That part did not interest me as much, and I skimmed it.

What am I doing to help kids achieve?

How do I know when they are there?

What is the evidence?

  It all started with a class my son and I took together at Marc Adams School of Woodworking. To make a long story short, we started on a Saturday morning with nothing and left Sunday afternoon with a custom built longboard. (Think skateboard but...well...longer). It was a great class taught by Chris Gochnour. So what does this have to do with chemistry? The word spread after we got home. Nephews, nieces and friends wanted one. My princinpal even said, "Hey, we have a handful of kids who love skateboarding that we are trying to reach. Ever consider starting a club?" (That tends to be code for "Thanks for volunteering...") So the challenge was on. Would it be possible to make a decent longboard without a gold plated workshop and a master craftsman standing over my shoulder to answer any and all of my questions? Maybe...with the help of a little science...

  Most modern skateboards or longboards are made by a process called bent lamination. Essentially it consists of taking thin strips of wood called "veneer" and gluing them together. It is similar to creating homemade plywood. This has a couple of advantages. First, the process produces an extremely stable strong product that does not expand or contract in different weather and usually bends but does not break. Think "material science" in action. Another advantage is that once the veneer "sandwich" is glued together and before it dries, it can be placed over a custom styrofoam form. It will dry in the shape of the mold. It is much easier to shape and curve wood this way than to do the same with a large chunk of wood that would need to be steam bent or sculpted. There are also a great gas law applications in the process. The veneer sandwich and mold are placed in a thick plastic bag, sealed and the air is pumped out of the bag. In theory, the column of air above the bag is pushing down with a pressure of about 12 to 14 pounds per square inch. This is great for clamping the curved veneer to the mold. There is a problem. Most vacuum systems with the bag can run close to $1000. That is a big chunk of change for one skate board. However, there is a company in Canada called "Roarocket". Here is the genius behind their system called the "Thin Air Press". They provide a thick bag that has a tar like substance that completely seals the bag and a one way valve used for evacuating the air. A person can place the veneer and mold in the bag, seal it and start to pull most of the air out with a shop vacuum. This will not be enough. The shop vac pulls a large amount of air out quickly but it is low pressure. To get to higher pressures required for the pressing, there is a hand pump that takes small amounts of air out slowly but a person can get to higher pressures. Once most of the air is out, atmospheric pressure takes over and clamps down the veneer. It is only required initially for a person to check back every few minutes to make sure there is not a leak in the bag.The total time to evacuate the bag and get a good seal usually only takes a few minutes. The bag does not evacuate air to the degree of a professional system, but it gets pretty close, is a tenth of the cost and is "good enough". It is great to see gas laws and air pressure at work.

  Once the board is out of the bag, work is done to cut and sand it to its final shape. The problem now is the art work that is placed on the board or what people call the "deck". Honestly, I have little to no art ability. I do know something about intermolecular forces and chemicals. Steve Ramsey came across a simple and inexpensive way to transfer images from an ink jet printer to a piece of wood. It is all about utilizing the intermolecular forces involved. Steve takes a sheet of labels from a office supply store and takes off all the labels but saves the paper that was attached to the labels. The paper is really similar to a stiff wax paper and seems to be extremely nonpolar. Ink from the printer, on the other hand, is pretty polar. Steve feeds the label free wax paper into the printer, wax side up. The ink is on the paper but is wet and does not stick. He then carefully and quickly places the ink side of the paper on the wood. The somewhat more polar fibers of the wood immediately bond with the ink and the image is transfered to the wood. It pretty much soaks the ink up like a sponge. Next, a coat of polyurethane is placed on the wood. The polyurethane over time reacts with oxygen and the polyurethane chains are made even longer and with more tangles. The resulting coat is chemistry at work again. The result is long tangled polymers which end up being similar to coating the board in a protective plastic. This method works amazingly well. My nephew is a huge fan of the band The Gaslight Anthem. They have some great looking film noir type concert posters. I used this process to place these posters on the longboard and it turned out great. Caution... more chemistry occurs with polyurethane than most people know. Oxygen reacting with polyurethane is an exothermic reaction (again...more chemistry). There have been reports of people taking rags soaked in polyurethane and just throwing them in a trash can. In some cases the polyurethane reacts with oxygen and produces enough heat to start a fire...especially if saw dust is around.

     Next, it is time to put on the wheel assembly or what the skateboard community calls "trucks".  The key is to get the trucks placed exactly in the middle of the board at both ends.  Suppose you are dealing with some kids who hate math.  How do you teach them to use something they hate?  Simple.  You cheat and use geometry and don't tell them it is math.  The ancient world build some pretty cool structures and never used tap measures and auto cad.  How did they do it?  I do not have all of the answers but Jim Tolpin and George Walker have most of them.  For centuries people built tables, chairs and buildings really well without ever using a ruler.  Instead they used a sector, a divider and simple whole number proportions.  Jim demonstrates in this video called "Sector Basics" how to quickly, easily and efficiently find the center of any segmant, such as the width of a longboard, faster and probably much more accurately than I could ever measure with a tape measure.  It utilizes similar triangles and works like a charm.  It can get the dead center every time within seconds.

     Why bother will all of this???  I just had a conversation with a passionate teacher and good friend who really cares about her students.  She is struggling.  She sees the value of chemistry but how do you really convey that to a teenager that this "stuff" is important?  Why should a kid care?  What if that kid could use gas laws, chemical reactions, geometry and material science to make a really cool longboard that was custom built and their very own? Would they care then?  The job we do is hard and somedays feels like it is impossible.  We cannot always be reinventing the wheel.  This time now might be the right time to "tweek" a few things and try something new that might reach the kid that people may have thought could not be reached.  It can be fun, exciting, I get to learn new things, most importantly kids might get excited and when I test out the board, fall and break my arm I will be able to tell the doctor...."It's O.K....I'm a science teacher..."

Back to school time means back to lab time too. Students new to chemistry have a lot on their plates the first few labs—learning unfamiliar safety procedures, becoming accustomed to writing lab reports, even figuring out which glassware they’re looking for in their lab space. How can teachers help them to navigate this newness? Two articles in the July 2016 issue of the Journal of Chemical Education are useful resources for “back to lab” time.

Familiarity with Lab Equipment

Could your students pick an Erlenmeyer flask out of a glassware lineup? What about a watch glass? A drawerful of equipment that we find familiar can be a confusing jumble to others. Kavak and Yamak’s JCE article Picture Chem: Playing a Game To Identify Laboratory Equipment Items and Describe Their Use (available to JCE subscribers) starts with some of the most common glassware and lab equipment and turns their identification into a game with visual and text components. Students split into two teams, then take turns reading aloud definitions and functions of a piece of equipment from a card drawn from the game pile. An opposing team member attempts to identify the equipment’s name, but must also find its picture on the gameboard (see figure).

ed-2015-00857w_0003.jpeg

Instead of the gameboard, which would need to be projected or shared in a central location for teams to see, you could have an actual collection of your lab equipment at a table. You can also customize which cards to include in the game—if you don’t use separatory funnels, don’t use that card. The cards and gameboard are available to subscribers in the article’s online supporting information as a pdf. There are some spelling errors in the cards, plus a picture of the gameboard is used as a graphic behind the facts about each piece, making the text harder to read. The game was tested with chemistry pre-service teachers, who provided analysis of its strengths and weaknesses, along with possible extensions. I agree with the suggestion that it could be turned into an electronic version as well, for individual use.

For another resource, I appreciated Compound Interest’s post and downloadable infographic from last year: A Visual Guide to Chemistry Glassware. They are not all items you’d find in an introductory lab, but it’s an easy reference to a lot of common pieces.

A Meaningful Lab—No Experience Necessary!

Erdmann and March’s Laboratory Activity on Sample Handling and Maintaining a Laboratory Notebook through Simple pH Measurements (available to JCE subscribers) fills the common requirements of an early lab: students practice sample handling, collect and record data, and write up the lab. After learning a bit about pH, students are asked to predict how the pH of three ammonia concentrations (0.00625 M, 0.0125 M, and 1.0 M) would trend. Would pH increase or decrease with increasing concentration? The main technique is to qualitatively measure pH of ammonia samples using paper pH strips. 

If that's where it ended, this would just be a typical lab. The authors add a twist: students are informed that not all of the sample containers are properly labeled. This, along with the somewhat subjective nature of determining the color of a pH strip for samples that are close in pH, provides ample fodder for discussion within lab groups and for discussion as a class. Individual students test each sample three times, then work with their group to agree on a single pH value for each sample to report to the class. After all groups report, each is then given an unknown. After testing of the unknowns and reporting each group’s agreed-upon value again, a class discussion is held. The authors offer descriptions of likely discussion topics in the figure labeled “Box 1” in the article. Can students analyze patterns in the reported data to determine which samples are likely mislabeled? Did any students feel pressured to change their results so they matched the rest of their group?  What are the ethics associated with lab notebooks? What happens if a student forgot to record the code from his or her sample—is the experiment reproducible?

The article also has supporting information online. It includes a student handout, a table for mislabeling solutions, and an in-class assignment handout with rubric. There are both pdf and Word versions, if the instructor wishes to edit the wording to fit his or her situation.

Look for more resources in Mary Saecker’s post JCE 93.07 July 2016 Issue Highlights.

What Do You Use?

What do you use in your classroom during your first labs? Please share in the comments below, or in a separate post. Contributors can submit an article or share a "Pick" of another JCE article or other published resource. Submit a request to contribute. Questions? Contact us using the XChange’s contact form.

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In Chemical Mystery #7, a can of Coca-Cola was observed to sink in one container of water and yet float in another! This trick made use of the fact that the density of water changes with temperature. See the video below. For those that are interested, more information about this experiment can be found below the video.

Unopened cans of Coca-Cola have densities that are very close to the density of water. However, the density of cans of Coca-Cola will vary from one can to another. Although I have not tested this, it is my hypothesis that the variation in densities of unopened cans of Coca-Cola results primarily from variations in the volume of gas contained in the head space of each can. Unopened cans with larger headspace gas volumes will have lower densities than those with smaller headspace volumes (Figure 1). I think a great small research project would involve having students create and conduct tests to determine if this hypothesis – or any other explanation – is consistent with experiment.

cans of soda

Figure 1: Schematic of unopened cans of soda. The can on the left has a larger gas headspace than the can on the right. Thus, one would expect the can on the left to have a lower density than the can on the right.

Because of this variation, and because cans of Coca-Cola are very close to the density of water, some cans of Coke float – while other cans sink – in water. This observation alone makes for a great chemistry demonstration: add two separate cans of Coke to a single container of water (Figure 2). One can floats, while the other one sinks! Now how does that happen?

Do cans of Coca-Cola float or sink?

Figure 2: A Coke can with a slightly lower density floats in water at room temperature (left). However, most cans of Coke sink in water (right).

Now for the solution to Chemical Mystery #7: If we take the above demonstration a bit further, we can place the two cans of Coke into a container of very warm water. In this case, both cans sink (Figure 3). That’s because the density of water varies with temperature, becoming less dense as it is warmed. In the experiment filmed in the video above, one container of water was at 23^oC (D = 0.997 g mL^-1), and the other container of water was at 37^oC (D = 0.993 g mL^-1). I have never observed a can of Coca-Cola to float in very warm water, so essentially all cans of Coca-Cola have densities higher than 0.993 g mL^-1. However, I have found that roughly 10% of Coca-Cola cans float in water at room temperature. Thus, about 10% of Coca-Cola cans have a density somewhere between 0.993 and 0.997 g mL^-1.  

Coke cans in warm water

Figure 3: All unopened Coke cans sink in very warm water, which as a density that is lower than water at room temperature.

A word of warning here: if you plan to do this experiment in class, be certain to first find a can of Coke that floats in room temperature water. Occasionally I will buy an entire 12 pack of Coke cans and find that not one in the whole batch floats in room temperature water! It is helpful to use cold water (because of its slightly higher density) to identify the rare, floating Coke cans with lower densities. Also, be sure that no air bubbles become trapped underneath the cans. If this happens, the experiment won't always work as planned.  

If you present these lessons to students, consider pointing out that this experiment relates to how Galileo thermometers work. To make such a device, sealed glass bubbles of varying density – but close to the density of water – are enclosed in a column of water. The water in the container changes temperature with the surrounding air. As this occurs, the density of the water in the container also changes. As the temperature gets warmer, more of the glass bubbles sink. As the temperature cools, more of the glass bubbles float. By fine-tuning the glass bubbles with very specific densities, it is possible to tell temperature with a Galileo thermometer to within a single degree Fahrenheit. Wouldn’t it be really cool to make a Galileo thermometer using cans of Coca-Cola? Hmmm….maybe I’ll get some students working on this when they return in the fall…

The beautiful photographs in this publication just make you itch to go into the lab and try to reproduce them.  The structures appear to be ideal for lawn ornaments - delicate, colorful and very attractive.  Furthermore, they can be made with easily available materials, just sodium metasilicate, barium chloride, a flat piece of metal-coated glass, and carbon dioxide from the air. By controlling the pH, the temperature and the amount of CO₂ admitted, the authors were able to grow structures of precipitated SiO₂ or BaCO₃ on top of one another. Some of the complex structures they can grow strongly resemble green plants with red or purple flowers.

The shapes of the structures precipitated are the result of an intricate interplay of thermodynamics and kinetics.  Silicon dioxide and barium carbonate coprecipitate in aqueous solutions of barium chloride and sodium silicate in the pH range 8-12. In the experiment, precipitation is triggered by the diffusion of carbon dioxide into the solution to produce barium carbonate, and a gradient in pH is produced by the diffusion of CO₂ down from the surface of the solution.  The reaction that precipitates barium carbonate also lowers the pH of the solution near the crystals. This slows the formation of barium carbonate and triggers deposition of silica (SiO₂), which consumes acid and revives the barium carbonate reaction. The interplay of these reciprocal reactions forms various curved shapes, as the reagents are depleted regionally and hydrogen ions diffuse around the growing structures.  The higher the pH, the more carbonate is favored, but silica is most stable within a limited pH range. 

But wait a minute! How big are these structures?  The extended title of the article says that these are microscale, but the beautiful figures in American Scientist have no scale on them, so it is not possible to tell whether these can be seen with a magnifier or a microscope.  What about the colors? The solids precipitated in these reactions are SiO₂ or BaCO₃, both of which are colorless.  Where do the colors come from? What concentrations of reactants and what temperatures are used?  Unfortunately, none of the answers to these questions is found in American Scientist, and the published article also includes no references. The answers to the experimental questions can be found in Science2013 340, p. 832-836 and its Supplementary Materials. There, one learns that a typical “plant” is about 50 micrometers in size. The colors are all produced in the computer rendering, so they can be adjusted arbitrarily, and have no reality. After the solutions are degassed, carbon dioxide is introduced by partially uncovering the beaker in which the reaction occurs, and gas diffuses into the solution over a period of minutes, sometimes as small as two minutes.  Most of the reactions were run at room temperature (which was unspecified), but some structures were grown at 4 degrees Celsius.  Typical concentrations were 19.1 mM BaCl₂, 8.2 mM Na₂SiO₃, and a pH adjusted to 11.8. All of these growing conditions are accessible to even an amateur chemist, but an electron microscope is needed to see what you have grown.

Exploration of Instrument Design and Performance

The July 2016 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: cost-effective instrumentation, including 3D printed instruments and low-cost spectroscopy; laboratory instrumentation and equipment; effective teaching assistants in chemistry; laboratory experiments; resources for teaching; puzzles and games to introduce the periodic table.

Commentary

Marcy H. Towns and Thomas A. Holme examine the governance of the Division of Chemical Education over last 30 years in their Commentary The Division of Chemical Education Executive Committee, Board of Publication, and ACS Examinations Institute Board of Trustees: A Historical Perspective from 1985 to 2015.

Cost-Effective Instrumentation

Open Source Epifluorescence Microscopes: Cover Feature

Scientific inquiry need not be an expensive pursuit; many have successfully developed innovative yet economical scientific instruments or experiments for educational and other purposes. In Inexpensive, Open Source Epifluorescence Microscopes, Chris Stewart and John Giannini describe how to modify or build microscopes for fluorescent viewing using 3D printing technology or parts available at most hardware stores. Bright-field and fluorescent images of Tetrahymena thermophila cells taken using the 3D-printed version of the scope are shown on the cover. The cost-effective techniques discussed in this and additional articles listed below are intended to help promote and encourage scientific education, exploration, and innovation by students and teachers at all levels.

3D Printed Instruments

User-Friendly 3D Printed Colorimeter Models for Student Exploration of Instrument Design and Performance ~ Lon A. Porter, Benjamin M. Washer, Mazin H. Hakim, and Richard F. Dallinger

Transient-Absorption Spectroscopy of Cis–Trans Isomerization of N,N-Dimethyl-4,4′-azodianiline with 3D-Printed Temperature-Controlled Sample Holder ~ Dmytro Kosenkov, James Shaw, Jennifer Zuczek, and Yana Kholod

Low-Cost Spectroscopy

Teaching Beer’s Law and Absorption Spectrophotometry with a Smart Phone: A Substantially Simplified Protocol ~ Thomas S. Kuntzleman and Erik C. Jacobson

Optimization and Design of an Absorbance Spectrometer Controlled Using a Raspberry Pi To Improve Analytical Skills ~ Kristelle Bougot-Robin, Jack Paget, Stephen C. Atkins, and Joshua B. Edel

Construction and Characterization of a Compact, Portable, Low-Cost Colorimeter for the Chemistry Lab ~ Carrie M. Clippard, William Hughes, Balwant S. Chohan, and Danny G. Sykes

Low-Cost Instrumentation

An Inexpensive, Open-Source USB Arduino Data Acquisition Device for Chemical Instrumentation ~ James P. Grinias, Jason T. Whitfield, Erik D. Guetschow, and Robert T. Kennedy

Building a Microcontroller Based Potentiostat: A Inexpensive and Versatile Platform for Teaching Electrochemistry and Instrumentation ~ Gabriel N. Meloni

A Chemical Instrumentation Course on Microcontrollers and Op Amps. Construction of a pH Meter  ~ Nikos J. Papadopoulos and Andreas Jannakoudakis

Laboratory Instrumentation & Equipment

Laboratory Instrumentation: An Exploration of the Impact of Instrumentation on Student Learning ~ Don L. Warner, Eric C. Brown, and Susan E. Shadle

Picture Chem: Playing a Game To Identify Laboratory Equipment Items and Describe Their Use ~ Nusret Kavak and Havva Yamak

Laboratory Activity on Sample Handling and Maintaining a Laboratory Notebook through Simple pH Measurements ~ Mitzy A. Erdmann and Joe L. March

Effective Teaching Assistants in Chemistry

Chemical Education Research Characterizing Instructional Practices in the Laboratory: The Laboratory Observation Protocol for Undergraduate STEM ~ Jonathan B. Velasco, Adam Knedeisen, Dihua Xue, Trisha L. Vickrey, Marytza Abebe, and Marilyne Stains

An Intensive Training Program for Effective Teaching Assistants in Chemistry ~ Vera Dragisich, Valerie Keller, and Meishan Zhao

Development of an Advanced Training Course for Teachers and Researchers in Chemistry ~ Vera Dragisich, Valerie Keller, Rebecca Black, Charles W. Heaps, Judith M. Kamm, Frank Olechnowicz, Jonathan Raybin, Michael Rombola, and Meishan Zhao

Piloting Blended Strategies To Resolve Laboratory Capacity Issues in a First-Semester General Chemistry Course ~ Shayna Burchett, Jack Hayes, Annalise Pfaff, Emmalou T. Satterfield, Amy Skyles, and Klaus Woelk

Laboratory Experiments

Model Experiment of Thermal Runaway Reactions Using the Aluminum–Hydrochloric Acid Reaction ~ Suguru Kitabayashi, Masayoshi Nakano, Kazuyuki Nishikawa, and Nobuyoshi Koga

Studying Equilibrium in the Chemical Reaction between Ferric and Iodide Ions in Solution Using a Simple and Inexpensive Approach ~ Pavel Anatolyevich Nikolaychuk and Alyona Olegovna Kuvaeva

Electrochemical Study and Determination of Electroactive Species with Screen-Printed Electrodes ~ Daniel Martín-Yerga, Estefanía Costa Rama, and Agustín Costa García

Analysis of Two Redox Couples in a Series: An Expanded Experiment To Introduce Undergraduate Students to Cyclic Voltammetry and Electrochemical Simulations ~ Jay H. Brown

Using a Combination of Experimental and Mathematical Method To Explore Critical Micelle Concentration of a Cationic Surfactant ~ Jelena Goronja, Nataša Pejić, Aleksandra Janošević Ležaić, Dragomir Stanisavljev, and Anđelija Malenović

Facilitating Conceptual Understanding of Gas–Liquid Mass Transfer Coefficient through a Simple Experiment Involving Dissolution of Carbon Dioxide in Water in a Surface Aeration Reactor ~ Vivek P. Utgikar and David MacPherson

Investigating Bandgap Energies, Materials, and Design of Light-Emitting Diodes ~ Eugene P. Wagner

Resources for Teaching

Review of Planck: Driven by Vision, Broken by War ~ Jeffrey Kovac

Review of Top Drugs: Their History, Pharmacology, and Syntheses ~ Michael B. Jacobs

Using Balancing Chemical Equations as a Key Starting Point To Create Green Chemistry Exercises Based on Inorganic Syntheses Examples ~ John Andraos

Distilling the Archives: Puzzles and Games to Introduce the Periodic Table

Antonio Joaquín Franco-Mariscal, José María Oliva-Martínez, Ángel Blanco-López, and Enrique España-Ramos describe their research on A Game-Based Approach To Learning the Idea of Chemical Elements and Their Periodic Classification. This is related to a previous study on Students’ Perceptions about the Use of Educational Games as a Tool for Teaching the Periodic Table of Elements at the High School Level  by Antonio Joaquín Franco-Mariscal, José María Oliva-Martínez, and M. L. Almoraima Gil. In addition, past issues include numerous puzzles and games for introducing the periodic table:

Elements—A Card Game of Chemical Names and Symbols ~ Susan V. Alexander, Richard S. Sevcik, O'Dell Hicks, and Linda D. Schultz

ChemMend: A Card Game To Introduce and Explore the Periodic Table while Engaging Students’ Interest ~ Vicente Martí-Centelles and Jenifer Rubio-Magnieto

An Educational Card Game for Learning Families of Chemical Elements ~ Antonio Joaquín Franco Mariscal, José María Oliva Martínez, and Serafín Bernal Márquez

Cheminoes: A Didactic Game To Learn Chemical Relationships between Valence, Atomic Number, and Symbol ~ Luis F. Moreno, Gina Hincapié, and María Victoria Alzate


An Effective Method of Introducing the Periodic Table as a Crossword Puzzle at the High School Level
 ~ Sushama D. Joag


Developing and Playing Chemistry Games To Learn about Elements, Compounds, and the Periodic Table: Elemental Periodica, Compoundica, and Groupica ~ Eylem Bayir

At ChemEdX, you’ll find Dan Mayers’ periodic table board game.

A Cost-Effective Resource: JCE

Ninety-three volumes of the Journal of Chemical Education means you will always find something innovative—including the articles mentioned above, and many more, in the Journal of Chemical Education. Articles that are edited and published online ahead of print (ASAP—As Soon As Publishable) are also available.

Summer is here! Please consider submitting a contribution to the Journal of Chemical Education. Erica Jacobsen’s Commentary gives great advice on writing for the Journal. In addition, numerous author resources are available on JCE’s ACS Web site, including: Author Guidelines, Document Templates, and Reference Guidelines. The Journal has issued a call for papers on Polymer Concepts across the Curriculum, so consider submitting a contribution to our next special issue.

My students are bright and motivated. Most work hard and prepare for class and tests. They perform extremely well on district-wide tests and my own classroom tests. However, I see real weaknesses on cumulative assessments requiring high levels of application. My students simply do not retain the content knowledge. I want to restructure my course to exclude "unit tests" and include only cumulative assessments. I'll share my early ideas here, and I would love to hear your experiences.

In the past, I have given a traditional unit test at the end of each topic of study. The tests are comprised of 12-16 multiple choice questions and 5-7 free response questions. Students are not allowed to use calculators on the multiple choice, but they are free to use them on the free response. I have used online resources, exam test prep books, textbooks, and workbooks to get ideas for the questions. I also use released AP exam questions on the topic if they are available. In the end, I have between 20 and 25 questions to assess their understanding of that particular unit of content, for example, atomic structure.

My revised idea is regularly scheduled comprehensive tests assessing the student's ability to apply all of the content learned so far in the semester. The test period is 90 minutes. I envision my new tests having 20 multiple choice and 5 free response questions. The trick will be to write or find good questions that apply multiple concepts without requiring knowledge of ALL of the semester's content. I hope to find many in the released AP exam questions, but there simply aren't enough released questions for the re-written exam.

I would love to hear your thoughts on any of the following questions.

• Are your tests cumulative?
• How long are they?
• How often do you give a test?
• Where do you find the best questions?
• Do you have other tips for helping students retain knowledge?