I’m not sure if it was my first exposure to the Diet Coke and Mentos geyser phenomenon, but it was the one with the biggest impact—EepyBird’s Extreme Mentos & Diet Coke video, first released in 2006. I loved it. The jump from a single geyser to a choreographed Bellagio-style array of fountains of soda. The likable lab-coated pair releasing the Mentos. The music.

This demonstration has continued appeal. Even more than that, it offers a high-interest opportunity for student (and teacher) exploration. Research has uncovered some information about how the geyser works, but we don’t know everything about it. Tom Kuntzleman, a regular poster on this site, has continued to investigate. He and Trevor Sims authored the Journal of Chemical Education article Kinetic Explorations of the Candy–Cola Soda Geyser last year and now in the May 2017 issue of JCE, Kuntlzeman, et al. open the topic up further with New Demonstrations and New Insights on the Mechanism of the Candy–Cola Soda Geyser, referencing other work on the subject such as Mentos and the Scientific Method: A Sweet Combination by Eichler, et al.

At this point, I’ll leave it to Tom to further pique your interest in delving into the experiment on your own. Visit his blog post Exploring the Diet Coke and Mentos Experiment (packed with great videos!), which he wrote to connect with this Especially JCE column.

More Everyday Materials

If you’ve read some of my previous work related to the Journal, you might know that I’m a fan of chemistry activities that students and I can do with materials I can pick up locally, like at grocery, hardware, and craft stores. Because of this, my other instant “read me” item in the table of contents for this issue was Matsuoka’s Using Silica Gel Cat Litter To Readily Demonstrate the Formation of Colorful Chemical Gardens.

In this demonstration, metal salts (iron(III), cobalt(II), manganese(II), copper(II) chlorides) are added to an aqueous solution of sodium silicate. Silica gel cat litter puts a twist on the delivery of the metal salts. Pieces of litter are placed in each metal salt solution to soak. Then a piece from a solution is added to a test tube of sodium silicate. The author points out the benefits of the litter: “In addition to reducing the preparation time for instructors, the use of cat litter in place of metal salt crystals is superior in that it reduces the volume of reagent consumed.”

Student involvement would likely be limited to observations of the delicate tube-like structures that form in the chemical garden. Most needed materials wouldn’t be available locally. What is the draw for use? The author explains: “As the reaction mechanism in the chemical garden experiment is complex, the aim is not for students to understand the mechanism per se but rather to promote curiosity about science in students through visible tube growth using this experiment. … Furthermore, high school students may learn the sort of development content that may lead to the pursuit of scientific principles such as the difference in the solubility of various salts, the meaning of semipermeable membranes, and osmotic pressure.” For a quick look, take six seconds of your day to watch a time-lapse video showing crystal growth in several of the gardens, available in the demo’s online Supporting Information.

More from the May 2017 Issue

Mary Saecker offers her round-up of all the content from this month’s issue of the Journal. Visit JCE 94.05 May 2017 Issue Highlights. She included the two articles mentioned in this Especially JCE under the heading “New Twists on Classic Activities” and shared an additional link to a past JCE Classroom Activity about a crystal garden investigation.

Have something to say about a current or past article from JCE? We want to hear from readers! Start by submitting a contribution form, explaining you’d like to contribute to the Especially JCE column. Then, put your thoughts together in a blog post. Questions? Contact us using the ChemEd X contact form.

So this time of 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 am doing the classic Qualitative Analysis of Cations and Anions that is published by Flinn Scientific. If you are unfamiliar with it, it is a lab that takes many hours to do. It separates six cations and six anions by very chemical means. It was a mainstay of laboratory programs 50 years ago. Flinn has reworked it to remove a few troublesome ions (Mercury and lead but I think they should still be there).

The advantage to this lab for this type of activity is that it takes almost two weeks of my one hour class periods. The two weeks following the AP exam is pretty hectic and unpredictable for my students. They are all in a variety of AP classes and I do not ever know how many will be out on any given day. So I like that I can set this lab out and let them work at their own pace. It is a very nice opportunity for me to talk with each of them in depth to get a feeling for what they understand and what they don’t. It is a great time to talk with each about their lab skills and help them develop them further in a very relaxed atmosphere. I typically stay afterschool one day and give anyone who wants a chance for two hours of uninterrupted time to work on the lab if they need it. Kids work at their own pace and it is a nice relaxing way to spend to otherwise stressful weeks.

The grading of this activity is very simple for me. After the students have had a chance to run through the whole scheme I give them a bottle with three to four unknown cations and the same for anions. I have them identify what is present and give them five points for everyone they get correct and take off five for every mistake. It only takes me five minutes to grade an entire class set of this lab.

I do want to mention that setting this experiment up was no small undertaking. It required about ten hours and a great deal of money. Many of the chemicals needed to be ordered because they were not typically in my stock room and I needed to get three hundred dropper bottles to accommodate the 8 stations of 4 kids each that I run for lab. I also needed to get a table top centrifuge which I surprisingly discovered I had never purchased before. But the good news is that I figure after my initial outlay to set the lab up I can probably run it for 25 years without having to buy any more supplies. It takes a great deal of storage space but it sets up quickly and easily once mixed.

I am very fond of the phrase “Spending time to save time”. I love a good experiment that I can prepare and then box up for easy use next year.

By Andres Tretiakov and Tom Kuntzleman

A classic experiment involves use of the permanganate ion (MnO₄^–) to test for the presence of oxalic acid (C₂H₂O₄) in rhubarb stems. Oxalic acid reduces the colored permanganate ion, which contains manganese (VII), to the colorless manganese (II) ion. In the process, oxalic acid is oxidized to carbon dioxide:

2 MnO₄^–(aq) + 5 C₂H₂O₄(aq) + 6 H₃O⁺(aq) à 2 Mn²⁺(aq) + 10 CO₂(g) + 14 H₂O(l)

A video of this experiment can be seen below:

However, the common explanation¹ that oxalic acid is responsiblefor the color change may not be correct. While oxalic acid is certainly present in rhubarb, it tends to be concentrated in the leaf, and not the stem.^2,3 In fact, over twice as much malic acid (C₄H₆O₅) than oxalic acid is present in rhubarb stems.^2,3 Furthermore, malic acid is also oxidized by permanganate ion⁴ to form oxaloacetic acid (C₄H₄O₅):

2 MnO₄^–(aq) + 5 C₄H₆O₅(aq) + 6 H⁺(aq) à 2 Mn²⁺(aq) + 5 C₄H₄O₅(aq) + 8 H₂O(l)

Thus, it is likely the case that malic acid is the predominant cause of the reduction of permanganate ion when rhubarb is placed in solutions of permanganate. To test this idea, we decided to place some super sour candies⁵ in solutions of permanganate. These candies contain relatively large amounts of malic acid, which is the component that provides the extreme tartness. Check out the results of these investigations in the video:

Realizing that malic acid can reduce permanganate, we decided to test this idea further using apples. The tart flavor of apples comes from malic acid, which makes up 98% of the acid content of apples.⁶ As you might expect, the sour-tasting Granny Smith apple variety contains roughly 2.5 times more malic acid than the sweeter tasting Red Delicious apple.⁶

It is known that the malic acid content of apples decreases as they ripen. This is probably why unripe apples taste so sour. We think it would be fun to use this permanganate test to qualitatively compare the amount of malic acid in apples during the ripening process. Do you have suggestions for other investigations based on the experiments presented here? If you have any ideas – or better yet, try some experiments on your own – be sure to let us know!

In closing, we note that our investigations and experiments do not prove that malic acid is the main contributor to the loss of purple color when rhubarb is placed in permanganate solutions. However, they do strongly indicate that this is the case. What kinds of tests do you think we could conduct to strengthen the case that it is the malic acid in rhubarb which decolorizes permanganate in this classic experiment? We look forward to hearing from you!

Tom’s note: Andres Tretiakov, is a science technician at St. Paul’s School in London. He is a chemist and science enthusiast who enjoys making pyrotechnics and other energetic materials. Andres has shared with me several experimental ideas to share on ChemEdX. This blog post represents the results of investigating one such experiment. Hopefully, Andres and I will be able to share additional collaborations in the future. You can follow Andres on Twitter @Andrestrujado, and be sure to check out his YouTube channel.

NOTE: we used Jungle Brand Clear Water aquarium treatment (purchased at a local pet store) as a source of permanganate ion.

References:

1. http://www.sserc.org.uk/national-5/1131-chemical-changes-and-structure-n5/3065-rhubarb-rhubarb

2. http://www.compoundchem.com/wp-content/uploads/2015/04/The-Chemistry-of-Rhubarb.png

3. http://www.ct.gov/caes/lib/caes/documents/publications/bulletins/b424.pdf

4.https://www.researchgate.net/publication/283428415_Kinetics_and_oxidation_mechanism_of_lactic_and_malic_acids_by_permanganate_in_acidic_media

5. See, for example, http://www.impactconfections.com/warheads/

6. http://www.sciencedirect.com/science/article/pii/S0308814606006157

I try to examine activities an multiple levels. First on the list, I want to know if my students will be engaged and learn something. Second, how difficult is it for me as a teacher to actually pull it off? One of the most important questions...are the students learning chemistry or just having fun? This is the first year I have attempted the following activity.  tudents were engaged in the real world connection, they asked questions, it transitioned into some chemistry concepts and even some parents got involved. The activity involved acid, bases, pH and food.

Last year I had the honor of meeting Dr. Janet Marshall from Miami University Ohio at a regional ACS meeting.  Dr. Marshall teaches classes that involve food, chemistry and biochemistry. She actually received a grant to turn half of her chemistry lab into a kitchen. She shared a lab with us that involved chocolate muffins and chemistry (how can you not like this?). Here is the essence of the lab. Students have the chance to make three different types of chocolate muffins.  ust before they cook each of the batches they take some of the batter and test the pH. Each batch has a slightly different pH. One batch is slightly acidic (version #1). Another batch is slightly basic (version #3). This has an impact on the muffins. As it turns out, American cocoa can act as a levening agent and is slightly acidic. In version #1 there were more ingredients to react with the acidic cocoa and the muffins turned out a bit more dense in texture with a slightly different flavor. As the recipes changes  the cocoa has a chance to act more as a levening agent. The texture of the muffin changes (more "fluffy") as does the flavor. Dr. Marshall in an email correspondence was able to explain it much better...

"For the chocolate cake/muffins variations, version #1 was the most acidic (batter pH ~ 6) and version #3 was more alkaline (batter pH ~8). The reason has to do with the acidic/basic ingredients used to leaven the cake.  Specifically, American cocoa is rather acidic (pH ~5) due to the fermentation process. The ethanol produced during fermentation is oxidized to acetic acid so the cocoa provides a source of acid. The milk (either buttermilk or whole milk) also provides an acid source, primarily in the form of lactic acid (more in buttermilk). The baking soda (sodium bicarbonate) used in versions #2 and #3 reacts as a base to neutralize these acids. Lastly, the baking powder is balanced in terms of acid/base. Therefore, in version #1, the key acid/base ingredients are buttermilk, cocoa, and baking powder. The baking powder is essentially neutral and there is not an alkaline ingredient (such as baking soda) to counter-balance the acidic buttermilk and cocoa.  Therefore, version #1 is the most acidic of the three options. I hope this helps answer your question. I adapted these recipes from "How Baking Works" (reference provided on the handout) to develop this lab experiment.  - " May 21st 2017

So here is how the activity played out in the classroom: It was the last two weeks of school just after prom, after weeks of AP and state testing and I was trying hard to teach as summer was approaching and the weather was improving. I had never done this activity so I introduced it as an extra credit activity. Kids could cook these at home and I would need a picture of them with a parent or guardian to make sure they did not just buy some at the store. They would come in and we would "eat" the experiment. I also pulled in the current issue of "Chemmatters" and we served different coffees and tested the pH. Given the onslaught of previous testing the students had just survived most of the "assessment" questions were informal. We just sat around, drank coffee and ate muffins while talking about the acid base chemistry of it all and how pH can change texture and taste. I have several students who like to cook and I think appreciated the break from traditional work. Overall, I would consider it a success. I will post the lab from Dr. Marshall. I do not have a "key" because we did this more as an activity. Let me know what you think.

Are you are concerned about recent positions taken on climate change by political leadership in the United States? Do you agree with 97% of climate scientists who are convinced that human-caused climate change is an immediate, serious problem for our planet? Does it bother you that the issue of climate change has caused people to question the integrity of both science and scientists?

If you answered yes to any one of the questions above, I have a summer homework assignment for you:  

Take the online course entitled “Denial 101x: Making Sense of Climate Science Denial”, led by John Cook at the University of Queensland in Australia. The course is hosted on the edX platform, and you can take it for free! During this course, you will hear from several of the climate scientists who have their sleeves rolled up and are actively working on the problem. This course will teach you the reasons why 97% of climate scientists are convinced that the problem of human-caused climate needs to be dealt with now. Because the course covers how to effectively correct scientific myths and misconceptions, you can even pick up some techniques for teaching, Finally, you will learn about several topics in climate science that naturally connect to the chemistry curriculum such as:

Isotopes: Isotopic studies have shown that the ratio of ¹²C/¹³C in atmospheric CO₂ has increased in a manner consistent with the excess CO₂ in the atmosphere originating from fossil fuels.

Density: A significant factor in global warming-induced seal level rise is thermal expansion of water.

Atmospheric chemistry / chemical reactions: As the amount of carbon dioxide in the atmosphere increases, the amount of oxygen in the atmosphere decreases.

Kinetic-molecular theory: Increased global temperatures means increased precipitation, which means increased snowfall. That’s right, more snowfall can be expected in some areas due to global warming. Who knew?

Gas laws: Warmer temperatures in the lower portion of the troposphere have increased, causing it to expand. Conversely, lower temperatures in upper regions of the atmosphere have shrinking.

Quantum mechanics: Infrared light emitted by the earth is absorbed by atmospheric H₂O and CO₂ molecules, even though these molecules do not absorb visible light from the sun.

Henry’s Law / Equilibrium: About one quarter of the CO₂ emitted by fossil fuels is absorbed into the oceans, decreasing ocean pH.

Acid Base chemistry / K_sp: Lower ocean pH causes calcium carbonate in various organisms (coral reefs, sea shells) to dissolve.

Perhaps you feel a bit helpless about human-caused climate change. However, we science teachers need to recognize our great power regarding this important issue. We can teach future citizens and world leaders how to evaluate the evidence regarding our rapidly changing climate. We can help others recognize scientific myths, misconceptions, and science denial. Perhaps best of all, we can inspire the next generation of scientists who will go on to solve this problem.

It is my hope that science teachers of all stripes will work together to develop curriculum that will equip our students to do all these things and more (you can see an example of something I have tried along these lines in my chemistry classes here). I would encourage you to start thinking about ways to incorporate climate change and global warming – often – in your science classes. Taking the online course “Making Sense of Climate Science Denial” will provide you with numerous tools to do just that.

A voice piped up, “What if you tried it with a bigger marble?” I was thrilled to hear the third grader’s suggestion. It was a great extension to consider in the group experiment we were doing, but it was bigger than that. It was that the student had been automatically considering the “what if” possibilities of science, unprompted by me.

Blue Bottle Experiment: Learning Chemistry without Knowing the Chemicals (available to subscribers) in the June 2017 issue of the Journal of Chemical Education highlights the “what if” possibilities, on both the instructor and student sides of the classroom coin.

To begin, it shows the results of JCE authors considering “what ifs” related to the classic blue bottle experiment. If you haven’t seen it before, a solution in a plastic bottle undergoes multiple cycles of turning from colorless to blue and back again, as it is shaken and left to stand. They have developed resources for the use of what is often a demonstration so that students can use it in the laboratory. While the authors designed it to use with undergraduates (mostly nonchemistry majors) as a first lab experiment, it would also be an accessible experience for high school students. Each experiment also has suggestions for alternative procedures connected with certain parts. For example, they describe three different ways that you might provide a solution that has no air present in its container to help students realize that it plays a role in the reaction.

The “what ifs” for the students come in the series of suggested experiments. Students investigate the bluing process itself, finding that an atmospheric gas plays a role, but can then take it further by considering the way the solution is stirred, its temperature, and finally, other variations of their own choosing in a student-designed portion. The entire series was originally offered in a four-hour lab. I appreciate that the authors give a variety of experiments, but also understand that not all teachers will be able to use all of them. They provide tips for how you might pick and choose, and a suggested progression. They also include ideas for what students might consider during the open-ended investigation. Online supporting documents are included in Word format, so you can edit to your selected pieces.

In the abstract, don’t let the phrase “reaction mechanism” scare you off. The authors use a simplified treatment of the reaction, not sharing the specific compound names during the process. What they describe as a “mechanism” is more of a description of what happens, in an equation-style shorthand. For example, going from colorless (a leuco form of the compound, "L") to blue "B", through the addition of air "A" is shown as

L(aq) + A(g) à B(aq)

I have my own “what if…” I am curious as to how some of the suggested procedures would work with the chemicals used in the 2003 JCE Classroom Activity Out of the Blue. It used reactants available in stores, such as vitamin C powder and methylene blue and copper found in aquarium store products.

More from the June 2017 Issue

This post highlights just one piece of this month’s issue. Don’t miss the rest! Mary Saecker offers her summary of the content in JCE 94.06 June 2017 Issue Highlights.

Want to share your own “what if” moment related to an experiment or activity you’ve tried from the Journal? We want to hear! Start by submitting a contribution form, explaining you’d like to contribute to the Especially JCE column. Then, put your thoughts together in a blog post. Questions? Contact us using the ChemEd X contact form.

Engaging Participation and Promoting Active Learning

The June 2017 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: materials science and nanotechnology laboratories, promoting active learning, catalysis and kinetics, blue bottle reaction, cost-effective instrumentation, resources for teaching, from the archive: anchoring concept content maps.

Cover: Properties of Semiconductors

ZnO nanorods grown on conducting glass (upper left) can serve as an experimental introduction to crystal orientation (background scanning electron microscopy image and upper-right powder X-ray diffraction scan) and to semiconductor properties. When light excites electrons into the conduction band, changes occur: the change in photoelectrochemical current in the presence of UV light is shown center right; the large difference in resistance of the sample with and without illumination is shown lower right; the band edge in the absorption spectrum is shown center left; and the decolorization of methylene blue is shown lower left. For further details see the laboratory experiment, Properties of Semiconductors: Synthesis of Oriented ZnO for Photoelectrochemistry and Photoremediation, by Emma Koenig, Ari Jacobs, and George Lisensky.

For additional materials science and nanotechnology laboratories in this issue see:

Controlled Synthesis of Nanomaterials at the Undergraduate Laboratory: Cu(OH)₂ and CuO Nanowires ~ Anderson G. M. da Silva, Thenner S. Rodrigues, André L. A. Parussulo, Eduardo G. Candido, Rafael S. Geonmonond, Hermi F. Brito, Henrique E. Toma, and Pedro H. C. Camargo

Measurement of Chlorophyll Loss Due to Phytoremediation of Ag Nanoparticles in the First-Year Laboratory ~ Kurt Winkelmann, Leonard Bernas, Brendan Swiger, and Shannon Brown

Printing Silver Nanogrids on Glass ~ Wesley C. Sanders, Ron Valcarce, Peter Iles, James S. Smith, Gabe Glass, Jesus Gomez, Glen Johnson, Dan Johnston, Maclaine Morham, Elliot Befus, Aimee Oz, and Mohammad Tomaraei

Graphene Oxide as Mine of Knowledge: Using Graphene Oxide To Teach Undergraduate Students Core Chemistry and Nanotechnology Concepts ~ Izabela Kondratowicz and Kamila Żelechowska

Introducing Students to Surface Modification and Phase Transfer of Nanoparticles with a Laboratory Experiment ~ Alaaldin M. Alkilany, Sara Mansour, Hamza M. Amro, Beatriz Pelaz, Mahmoud G. Soliman, Joshua G. Hinman, Jordan M. Dennison, Wolfgang J. Parak, and Catherine J. Murphy

Exploring the Fundamentals of Microreactor Technology with Multidisciplinary Lab Experiments Combining the Synthesis and Characterization of Inorganic Nanoparticles ~ Noémie Emmanuel, Gauthier Emonds-Alt, Marjorie Lismont, Gauthier Eppe, and Jean-Christophe M. Monbaliu

Synthesis and Characterization of Zeolite Na–Y and Its Conversion to the Solid Acid Zeolite H–Y ~Terence E. Warner, Mads Galsgaard Klokker, and Ulla Gro Nielsen

Promoting Active Learning

Group Intelligence: An Active Learning Exploration of Diversity in Evolution ~ Christopher J. Parsons, Meisa K. Salaita, Catherine H. Hughes, David G. Lynn, Adam Fristoe, Ariel Fristoe, and Martha A. Grover (This article is available to non-subscribers as part of ACS AuthorChoice open access program.)

Engaging Participation and Promoting Active Learning through Student Usage of the Internet To Create Notes for General Chemistry in Class ~ Renee Monica Henry

Using Undergraduate Facilitators for Active Learning in Organic Chemistry: A Preparation Course and Outcomes of the Experience ~ Hannah E. Jardine and Lee A. Friedman

Cultivating Advanced Technical Writing Skills through a Graduate-Level Course on Writing Research Proposals ~ Brian D. McCarthy and Jillian L. Dempsey

Catalysis and Kinetics

Heterogeneous Catalysis with Renewed Attention: Principles, Theories, and Concepts ~ Franck Dumeignil, Jean-François Paul, and Sébastien Paul

Show Yourself, Asparaginase: An Enzymatic Reaction Explained through a Hands-On Interactive Activity ~ Josell Ramirez-Paz, Bonny M. Ortiz-Andrade, Kai Griebenow, and Liz Díaz-Vázquez

Bioelectroanalysis in a Drop: Construction of a Glucose Biosensor ~ O. Amor-Gutiérrez, E. C. Rama, M. T. Fernández-Abedul, and A. Costa-García

Lipase-Mediated Kinetic Resolution: An Introductory Approach to Practical Biocatalysis ~ Pamela T. Bandeira, Juliana C. Thomas, Alfredo R. M. de Oliveira, and Leandro Piovan

Enzyme Kinetics Experiment with the Multienzyme Complex Viscozyme L and Two Substrates for the Accurate Determination of Michaelian Parameters ~ Nelson Pérez Guerra

Synthesis of Dichlorophosphinenickel(II) Compounds and Their Catalytic Activity in Suzuki Cross-Coupling Reactions: A Simple Air-Free Experiment for Inorganic Chemistry Laboratory ~ Todsapon Thananatthanachon and Michelle R. Lecklider

Oxorhenium Complexes for Catalytic Hydrosilylation and Hydrolytic Hydrogen Production: A Multiweek Advanced Laboratory Experiment for Undergraduate Students ~ A. Ison, E. A. Ison, and C. M. Perry

Linear or Nonlinear Least-Squares Analysis of Kinetic Data? ~ Charles L. Perrin

Agreement, Complement, and Disagreement to “Why Are Some Reactions Slower at Higher Temperatures?” ~ Yingbin Ge

Blue Bottle Reaction

Blue Bottle Experiment: Learning Chemistry without Knowing the Chemicals ~ Taweetham Limpanuparb, Cherprang Areekul, Punchalee Montriwat, and Urawadee Rajchakit (See Erica Jacobsen's Especially JCE: June 2017 for a discussion of this article.)

Direct Visualization of Scale-Up Effects on the Mass Transfer Coefficient through the “Blue Bottle” Reaction ~ Patrick M. Piccione, Adamu Abubakar Rasheed, Andrew Quarmby, and Davide Dionisi

Cost-Effective Instrumentation

Inexpensive Miniature Programmable Magnetic Stirrer from Reconfigured Computer Parts ~ Conan Mercer and Dónal Leech

An Easily-Assembled Soxhlet Extractor to Demonstrate Continuous Extraction ~ Kevin M. Jones, Iain A. Smellie, and Iain L. J. Patterson

Resources for Teaching

pKa Values in the Undergraduate Curriculum: What Is the Real pKa of Water? ~ Todd P. Silverstein and Stephen T. Heller

A Python Program for Solving Schrödinger’s Equation in Undergraduate Physical Chemistry ~ Matthew N. Srnec, Shiv Upadhyay, and Jeffry D. Madura

From the Archive: Anchoring Concept Content Maps

This issue features a Comment on “Analyzing the Role of Science Practices in ACS Exam Items” by James T. Laverty, Sonia M. Underwood, Rebecca L. Matz, Lynmarie A. Posey, Justin H. Carmel, Marcos D. Caballero, Cori L. Fata-Hartley, Diane Ebert-May, Sarah E. Jardeleza, and Melanie M. Cooper. This letter is in reference to the article (available open access) Analyzing the Role of Science Practices in ACS Exam Items by Jessica J. Reed, Alexandra R. Brandriet, and Thomas A. Holme. This article was also recently discussed at the ChemEdX Conference, Chemistry Instruction for the Next Generation. Additional seminal work by Tom Holme and co-workers is the development of the Anchoring Concepts Content Maps as developed in the following articles:

Building the ACS Exams Anchoring Concept Content Map for Undergraduate Chemistry ~ Kristen Murphy, Thomas Holme, April Zenisky, Heather Caruthers, and Karen Knaus

The ACS Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map I: General Chemistry ~ Thomas Holme and Kristen Murphy

Updating the General Chemistry Anchoring Concepts Content Map ~ Thomas Holme, Cynthia Luxford, and Kristen Murphy

The ACS Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map II: Organic Chemistry ~ Jeffrey Raker, Thomas Holme, and Kristen Murphy

With over 94 years of content from the Journal of Chemical Education available, you will always discover something worth learning—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…do you have something to share and time to write it up for the Journal? For some advice on becoming an author, read Erica Jacobsen’s Commentary. In addition, numerous author resources are available on JCE’s ACS Web site, including updated: Author Guidelines, Document Templates, and Reference Guidelines.

A bit of background to serve as an introduction.

If you follow me on Twitter (@Thomsonscience) or read much from my blog here at ChemEd X: Thank you! And if you are in that category, you probably also know that I like using technology in my classroom to enhance the learning. I try to avoid using tech just to be using tech - but rather I hope to enhance and improve the classroom experience. 

Doug Ragan, a member of my Twitter PLN and a co-blogger here at ChemEd X, has inspired me over the years to experiment with resources such as the Atomic Dashboard, from Atomsmith Classroom. (Highlighted in a blogpost on ChemEd X) Based on this, and some Twitter interactions with Dave Doherty, I purchased the Molecule Lab App for my iPad. It's worth every penny of the current $9.99 price, in my opinion. I reviewed my use of the Molecule Lab App along with another online tool to help students understand Maxwell-Boltzmann energy distribution curves in a previous blogpost with an update here.

So enough background! In this Pick I would like to share a new product from Atomsmith, the Atomsmith Classroom Online. It's run in HTML 5, and thus no problems with Java, Flash, or any other system. Priced at $10.99/year for teacher access and $1.00/year per student, it is within reach of many school budgets. 

Along with many other features (given on a comparison page from Atomsmith), Atomsmith Classroom Online can be used for the following: 

• 3-D Live Lab/Gas Lab (modeling both ideal and real gas behavior) 
• Interactive 3-D Periodic Table (including properties such as atomic radius and ionization energy)
• Molecular Modeling of countless compounds, including the ability to search PubChem
• Within the molecular modeling, bond lengths and bond angles can be calculated anywhere within the molecule, and the 3-D Polar Surface can be shown, along with lines designating IMFs such as dispersion, dipole-dipole and hydrogen bonds. The model types include wireframe, stick, ball and stick, 3D Lewis Structures and Spacefill.
• Electron Configuration Lab
• Orbital Lab
• Reaction Lab

There is an entire collection of activities and experiments provided that can be used to guide the students through a number of topics. One characteristic of Atomsmith that I've always admired is the interactive nature of the company. I've had many interactions through Twitter and email with Dave Doherty, and some of these have led to new features. For example, Atomsmith Classroom Online now includes a Maxwell-Boltzmann distribution option when looking at a group of molecules in the Live Lab. Below is a screenshot using a sample of 20 atoms of helium and 20 atoms of xenon, showing the Maxwell-Boltzmann distribution of speeds after 100 picoseconds of simulation. The particles can also be labeled with their speeds, as shown here. That can get a bit crowded, but by pausing the simulation and moving the box around I was able to find the speed of each particle.

Image may be NSFW.
Clik here to view.

In summary, I think Atomsmith Classroom Online from Bitwixt is a phenomenal platform for enhancing the understanding of a variety of concepts in your chemistry classroom - and it should only get better as more features are added.

Say the words standardized test to most educators and you will likely notice a minor gag reflex. While I completely sympathize with this reaction given the frequently labeled testing culture that’s been far too often forced upon us within the past 15 years, I think it is appropriate to take a step back and recognize the meaningful role a standardized test can have on our curriculum and instruction. After a recent experience using an exam from the ACS Division of Chemical Education Examinations Institute¹, I was able to recognize that meaningful role. So, the purpose of this article is to provide useful information for anyone interested in the exam implementation process. I will follow a general “things I wish I would have known before ordering the exam” format.

Last year, I purchased the 2016 ACS High School Conceptual Chemistry Exam for a few reasons:

1) Since it’s a standardized test, I knew I could compare my students’ scores with the normative data gathered throughout the country².

2) The exam assessed students’ conceptual understanding, which is something I am always striving for as a teacher.

3) The exam contained 50 multiple-choice questions, which was convenient for scoring and implementation.

The process for ordering the exam is very simple. You request an order form online, fill out the paper order form indicating the quantity of the exam needed, and send it back to them. For scoring the exam, an answer sheet proof is provided and can be used to collect student responses. You can then choose to either send the paper copies or scans of the answer sheets back to the Institute which can usually be scored within a few hours. Once scored, the Institute sends back a nice statistical breakdown of your scores. Largely due to my own impatience, I chose to collect answers and score them using my own Scantron sheets.

I used the exam as a pre/post opportunity to measure growth, if any. I think using the exam in this manner has the potential for teachers to gain insight toward both content and pedagogical areas that they might not have previously emphasized as strongly in the past. For example, though my students’ scores improved, the average score on particle-based questions stayed relatively stagnate. I was surprised by this since I continuously stress a particle-based understanding in my instruction. But after thinking about it, I started to wonder that even though I show students particle diagrams all the time in my lectures, notes, and discussions, maybe I don’t provide them with enough opportunities to draw particle diagrams themselves. So, this summer, I am going to spend more time planning and creating these opportunities. The point is that this is an action I am taking because the exam shed some light on an aspect of my instruction that had not been previously visible in such a comprehensive way.

As for logistics, here is some general information about the test itself, pricing, and a brief description of what teachers might want to know if they are interested in implementing the test.

2016 High School Conceptual Exam Information:

• 50 multiple-choice questions
• Average time it took my students to complete was around 35 minutes (50 minutes is recommended)
• Though I’m not at liberty to discuss how many questions there are for each topic, I can say that the exam includes the following topics: Atomic Theory, Electromagnetic Radiation, Chemical Reactions, Gas Laws, Radioactive Decay, Bonding, Lewis Structures, Physical/Chemical Change, Solutions, Moles, Stoichiometry, Phase Changes, Kinetic Molecular Theory, Isotopes, Periodic Trends, Acids/Bases, Equilibrium, and Ionic Compounds.
• There are a number of particle-based questions, which align well with what the Modeling Instruction^TM curriculum emphasizes.
• The items are conceptually based rather than aligning to more traditional types of questions.

Pricing (exams come in sets of 5):

10-25: $2.00/each

30-80: $1.80/each

85+: $1.60/each

Pricing for other exams can be found here.

Things to keep in mind as a teacher:

• This is a highly secure exam. It is illegal to make copies of any kind. The exams must be kept secure at all times from arrival on campus, to storage of the exams, to use of the exams. Because of this, always keep the exams in a secure location and if you are allowing other teachers within your department to use the exam, make sure to communicate the importance of exam security and protocols for administration. During testing, the test must be kept secure meaning that students can only take the exam during a constantly proctored environment (being particularly careful not to allow students to capture any portion of the test as well – this specifically includes the use of cell phones or any device that would capture a digital image or copy of the test). Along with your purchase of the test, you will receive the policies and regulations for giving a secure exam.
• You will want to consider an appropriate time for giving the exam. I mistakenly gave the post-exam during the last week of school. In hindsight, I wish I would not have done this since the students were not in an appropriate state of mind to take the exam. Many expressed frustrations since completing the exam took time away from reviewing for finals. I won’t make this mistake next year.
• Make sure to effectively communicate to students why they are taking the exam. You really have to sell this. Students at my school often reflect the product of a “point grabbing” culture so I ran into several moments where students did not even want to try on the exam since it was not going to count toward their grade. If a student finishes the exam in less than 15 minutes, you know that no effort was applied and their score is inaccurate. I’m still thinking about ways to potentially incentivize the exam, since many students often lack the maturity to appreciate why this data is important to me. If you have any ideas on this matter, I would love to hear them!

If the High School Conceptual Exam does not fit your needs, no worries. The Institute has a number of exams available for different educational levels and those within different branches of chemistry (e.g. Analytical, Biochem, Inorganic, Organic, etc.)³. Though I’m sure there are other options out there, I found that using the ACS Examinations Institute was a great choice. Each exam goes through intense scrutiny and its creation is led by a committee of well-respected professionals that know what they are doing. I strongly encourage any chemistry educators out there to seek out an exam like this and use it to help make decisions about your own curriculum and instruction!

¹ "ACS Exams | ACS Division of Chemical Education Examinations Institute."https://uwm.edu/acs-exams/

² Since the 2016 High School Conceptual Exam is so new, there is not currently enough data collected for norming. However, it is only a matter of time.

³"Exams | ACS Exams - University of Wisconsin-Milwaukee."https://uwm.edu/acs-exams/instructors/assessment-materials/exams/

      I remember sitting in on Steve Sogo’s presentation and watching the video that accompanied his talk. As I watched the video, I saw something that didn’t necessarily have to do with the talk but had caught my eye. I noticed that certain laboratory glassware and equipment that was being shown while interviewing his students had been marked with colored tape and numbers. When I asked Steve about my observation he confirmed my observation and mentioned that this was the way that he kept his glassware and equipment organized for each of his different lab groups. I thought what a great idea.

    Fig. 1 - taken from Steve’s Youtube video: Benzoic Acid Lab 

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Now, I am sure I am not alone when I say it is frustrating when you have your students ready to start the lab and you have lab groups that are missing certain pieces of lab equipment from their lab drawers.  When your time in lab is limited to the time you have in class, then every minute is important. So I decided to take the time and to do some needed inventory.  I wanted to match equipment to its designated table.  Next, I wanted to make sure that each of my eight lab tables had the proper equipment needed to eliminate no more missing equipment.  Sure enough, as I began the inventory project, I had several tables missing equipment, so once everything was laid out and counted and organized then I had to make sure it was going to stay that way.  I had several rolls of colored tape and it was easy to then begin marking each of the pieces of equipment and glassware with tape.  Now a word of caution, don’t tape anything that will be directly heated.  As an example, the clay triangle and the crucible should not be taped.  However, the tops of beakers, graduated cylinders, and Erlenmeyer flasks, the bottom of Bunsen burners, and ring stands can all be marked.  Next, I placed a small piece of tape around the center faucet to designate the matching equipment to that table.  Also, I’m not concerned with the tape coming off as the equipment gets washed.  Overall, it didn’t really take that much time to tape everything once it was all set out.  On the plus side, by doing the inventory, I hope to move from four person lab groups to two person lab groups.  With four person lab groups, I was starting to see an increase in observers and a decrease in workers which led me to wonder how much learning was taking place in the lab. This is just my attempt to trying to keep things better organized in my lab which in return will help with safety as less students will have to move around the lab searching for equipment.  How do you keep your studnets laboratory equipment organized? If you have any other questions or further suggestions then please feel free to share. Thanks again to Steve Sogo for the idea.

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What are we doing to help kids achieve?

     POGIL stands for "Process Oriented Guided Inquiry Learning".  Over the years I have accidentally and somewhat intentionally been using POGIL activities. Students must work in teams, examine models and answer questions that become more complex based on the models and students hopefully build knowledge. I have had my ups and downs. It has been messy. Bottom line...here is what almost always happens...I eavesdrop on students talking like scientists. It is student centered and the comments would never come from students if I sat back and lectured. Somehow, I wound up at this conference for "advanced" POGIL practitioners. I am trying to keep it a secret that I have never really been advanced at anything and am hoping that by the time anyone figures this out the conference will be over.

     What truly amazes me is the phenomenal teachers who are thoughtfully trying to use solid pedagogy to help students. To be around these people is kind of like chicken soup for the science teaching soul. Everybody seems to have struggled with the best way to help students work in groups.Urik Halliday studied "postive interdependence" and applied it to his student groups. Lindsay Turk laminated a rubric that is used by groups during her POGIL activities. The groups constantly gain, lose and regain points based on how well they work together (I will definately road test this for a future blog).  She said it has changed her teaching and the culture of her classroom for the better. One teacher spends time with the students showing examples of great teams and compares them to groups of individuals. All are trying to inspire kids to work together to solve difficult science problems. They all care about the lowest and the highest performing student equally.

    One of the best parts, and it has only been day one, is how Urik Halliday was able to provide me some invaluable feedback on an activity I am trying to develop about solutions and solubility.  The students loved the "discrepant event" event but I was trying to put in about 15 concepts in one day. He provided wonderful insight on improvements to make it more managable and digestable for students without givng them the answer or being overwhelming.

     Bottom line...if you have not gone to a conference now is the time to give it a shot. It is hard to be a teacher and to keep a positive attitude. It helps and inspires one to be surrounded by those who struggle in a positive way. A conference with other science teachers is like giving your intellectual soul a gentle hug. You get to meet some amazing people and you can wear all of your nerdy chemistry shirts without any impunity from your kids. It is like Christmas in July and your students will grateful...give it a try and let me know how it goes....

As many school districts are moving toward incorporating student-centered curriculum and pedagogy, many teachers have found that it can be difficult to initiate a classroom culture that encourages students to embrace the change which calls for them to engage in discussions and take more responsibility for their own learning. Chemical Education Xchange (ChemEd X) is interested in learning about how teachers are creating a culture of student-centered learning in their classrooms. For this reason, we are initiating our content specific CALL FOR CONTRIBUTIONS centered on the concept of “Creating a Classroom Culture”.

Some examples of previous ChemEd X posts that fit the topic are linked here:

Some examples of items that you might contribute:

• Have you used a resource that you would like to recommend to help others create productive classroom culture? You might contribute a PICK review type manuscript. This manuscript type is generally one or two paragraphs in length.
• Share your experience of creating your own classroom culture within a blog post. Blog posts range between one and 10 paragraphs, are the least formal of ChemEd X manuscript types and are not peer reviewed.
• Share a project/lab/activity that you use to engage your students in an activity that helps promote a productive culture. It is recommended that the author include a student and teacher document. This manuscript type will be peer reviewed.
• You may want compile your own thoughts about creating a classroom culture including references to support those ideas in an ARTICLE. Articles are at least three paragraphs in length and are peer reviewed.

Please review the ChemEd X Contribution guidelines. We have provided a template that will help you organize your manuscript.

You can upload your submission using the Contribution page.

All submitted contributions are subject to peer review and acceptance by ChemEd X Editorial Staff.

Accepting contributions through August 20, 2017.

It's almost time for the Fouth of July here in the United States of America. In honor of my country, I'd like to share the following chemical mystery, which involves the colors red, white, and blue: just like the American flag! Check out the video below, and see if you can't solve the mystery of the colors appearing "out of the blue"! If you think you know how this trick works, be sure to share your ideas in the comments!

What are we doing to help kids achieve?

As mentioned in a previous blog, I just received a heavy dose of POGIL at NCAPP.

The part about POGIL that I previously glossed over was the “Process”. I saw the process of students thinking like scientists but what I struggled with, and I imagine many others do as well, is how students work together in groups. Yes...I know it is important but is this a big battle that I want to fight? I was fortunate to meet several people who have developed some wonderful “tricks of the trade” to help students work as “teams”.

First is the need to “sell” the idea of group work to students and parents. Teachers have found that there are times when one or both groups are less than enthusiastic about working as a team. Here are some ideas….

Laura Trout garnered the idea from “Circles of Learning; Cooperation in the Classroom” to have kids look at want ads in the newspaper that do not have to do with content specific jobs. What do the ads state? Almost all of them talk about teamwork….not just a bunch of individuals working as a group.

Many teachers challenge their students to examine winning teams and ask, "What do winning teams have in common?".

Several high school teachers discussed that they have honors and accelerated students who sometimes are opposed to working in groups because they want the “A” and don’t want to be dragged down by other people. The college professors responded with an interesting perspective. They often have freshman come in who were the top 5% in their class. They are now in a college class in which everyone is the top 5% and they are just seen as average for that class. This has a huge impact on their ego and performance. So if a student goes from “excellent” to “average” in the matter of a few months, what is the one thing they can do to stand out in a positive way? They can work well in teams. What college professor would not want that from a student?

Another teacher tells her students that when she places her students in groups and provides them defined roles (manager, technician, reporter...etc) it allows her to catch them doing things well that are not necessarily academic. This will help her be specific should she need to recommend them for a program. Most programs want evidence of student “soft skills” that many times can seem so intangible.

How do teachers implement group roles successfully?

The answer to this question varies from teacher to teacher based on the context of their situation and culture of their school. There are some common themes. First, as previously stated, there must be a reasonable rationalization for doing this. A key to “selling” the idea to students is that “you will need this in the future, whether it is in the workforce or college”.

Next, student teams must be given specific roles within the team and examples of what each member does. These roles are on posters or laminated sheets at every table. Different teachers use slightly different methods. Lindsay Turk from Sun Valley High School found that her students struggled with specific roles. She and a colleague came up with a unique twist. She has a simple three-point rubric with including roles that involve specific actions such as “Focus”, “Work Together”, “Help each other” and “Explain”. The sheet is laminated and each table gets one. As a group she quickly scores it with a dry erase marker. As the lab progresses she can change the score for better or worse and students can earn points back. If one group starts well they might get a 3 for “focus” but if they start talking about the homecoming game or dance, their score might go down to a 1. They still have a chance to raise this score if they get back on track. She has found that this method helps with “positive interdependence”.

Other instuctors use the specific roles suggested by POGIL. These roles are reflected in real world jobs.

Mark Morehouse from Fossil Ridge High School in Fort Collins has a great method to not only evaluate soft skills in students but also a way to provide positive feedback. Each group gets a sheet that has a number of categories such as “interpersonal skills”, “integrity”, “lifelong learning” and “professionalism”. Underneath each category is an example(s). As an example, under “Professionalism” is the statement “Demonstrates positive attitude toward work and others”. So the person in the group in charge of recording gets this form at the end of the lab, sees that his or her partner did this under “professionalism” and must write down a few words of evidence about demonstrating positive attitude toward work and others. Mark collects these throughout the semester. At the end of the semester he passes them back to students. Students see, and get positive feedback, about what they are good at and they notice the blanks. Mark asks students to write three paragraphs. The first paragraph should be about evidence showing good interpersonal skills (like “professionalism”). The second paragraph is about what they need to work on. The third paragraph should be about student insights and reflections. Students, in the end, get positive feedback and learn where they need to improve.

Urik Halliday proposed an idea that gives students incentives to work well together as a group. The incentive Mark uses is extra credit on an assessment about the activity. The extra credit is only given if every person in the group receives an A on the assessment. This extra credit has many advantages. One advantage is that it encourages students to help all the students in the group instead of leaving members behind. Members can get an “A” but are not penalized if one member is struggling. Supporting a struggling member helps to create a “positive interdependence”.

There seems to be common threads for teachers who successfully institute roles and teams in the classroom. First, they sell the idea based on how these skills help students in the future. They provide students with specific roles. Teachers then implement rewards.

Have you struggled with teamwork or roles in your classroom? Drop a comment and let’s share strategies. All are welcome…..

As part of a two-week Chemistry Modeling Workshop™ in Houston, TX, I had the opportunity to read the Journal of Chemical Education article “When Atoms Want” by Vicente Talanquer of the University of Arizona. I researched Dr. Talanquer and discovered he created a collection of simulations called Chemical Thinking Interactives (CTI). These digital tools illustrate many chemistry topics with a focus on the particulate nature of matter.

AP Chemistry teachers will no doubt be familiar with Talanquer’s photoelectron spectroscopy (PES) simulation. This resource became popular following the AP Chemistry redesign in 2013 and Jamie Benigna’s webcast for the College Board on PES that included it among the teaching resources. The new version, linked above, fixes the “stacking” problem that plagued the old version and makes students’ interpretations of the spectra much more efficient. Before this week, I was completely unaware this resource was part of a larger collection of excellent simulations that have the potential to hold a prominent place in any chemistry classroom.

The second simulation I want to highlight is entitled Activation and Temperature. This very simple simulation allows students to explore the connections between activation energy, chemical potential energy, and temperature. Most impressively, it explicitly connects the graphical, particulate, and symbolic representations of the reaction in a single screen so students can easily draw connections between the different representations as they watch the reactant molecules collide to form a transition complex and then product molecules. This will be a welcome addition to my kinetics unit this fall.

The third simulation that caught my attention is called Free Energy and Equilibrium. This simulation takes what is depicted as a static graph in many textbooks and allows students to manipulate the parameters to investigate the connections between the equilibrium constant, change in Gibb’s Free Energy, temperature, and entropy. This simulation would be useful as a demonstration, with an accompanying student worksheet, or as an avenue for students to explore at their leisure while they wrestle with the concept.

Also included are a student-friendly interface for graphing points and adding a line of best fit, an intuitive molecule illustrator for quickly drawing particle diagrams, and a particulate-level movie builder.

sim2.png

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I hope you take the time to explore the simulations available and share your thoughts. Which simulation do you think would be the most useful in your classroom? Does anyone already use these simulations and have activities or demonstrations designed around them?

In Chemical Mystery #10, plastic straws are observed to “magically” change color when waved in the air. Check it out in the video below:

This trick makes use of straws that contain thermochromic dyes,¹ which are dyes that display different colors at different temperatures.^2,3 The dyes in the straws happen to be colored (either red or blue) at cold temperatures but colorless at warm temperatures. It is obvious then, that the straws are colored when cool but colorless when warm.

But how is it that the straws only display color when they encounter one of two liquids and are subsequently waved in the air? Given the thermochromic nature of the dyes, one might guess that the color change somehow results because one of the liquids is cool, while the other is warm. However, both liquids are at room temperature! The difference results because one of the liquids is acetone, while the other is water. If you would like to see how I set up this experiment, check out the video below.

Room temperature is high enough to cause the thermochromic dyes in the straws to be colorless. Thus, straws placed in room temperature acetone or water will have no color. However, when a straw is removed from a liquid and waved in the air, residual liquid clinging to the straw evaporates off the surface of the straw. The energy to drive the evaporation (remember, evaporation is an endothermic process) come from the straw. Therefore, the straw loses energy – and drops in temperature – as the liquid evaporates. If the temperature drops enough, the thermochromic dye in the straw displays its color.

The color change only occurs in straws that have come into contact with acetone. Liquid acetone evaporates very quickly, due to the relatively weak intermolecular forces that exist between acetone molecules. Because of this, a straw dipped in acetone and waved in air will drop in temperature very quickly as acetone rapidly evaporates off its surface. The temperature drop is rapid enough to allow a color change to be observed in the dyes in the straw. Water molecules, on the other hand, have very strong intermolecular forces. As a result, a straw dipped in water and waved in the air will drop in temperature slowly: so slowly that the temperature of the straw does not drop quickly enough to register a color change.

This experiment allows for a discussion of the difference between thermodynamic and kinetic explanations. This experiment makes no sense if one compares the enthalpies of vaporization of acetone (31 kJ mol^-1 ) and water (44 kJ mol^-1).⁴ It actually takes MORE energy for water molecules to evaporate off of the surface of the straw than it does for molecules of acetone. Since this is the case, the greater temperature drop observed in the straws dipped in acetone must result from much more rapid evaporation of acetone molecules (as compared to water molecules) from the straw surface.

Be sure to drop me a line in the comments if you use this experiment in your classroom. If you do so, use caution when waving around the straw dipped in acetone, because droplets of acetone are often flicked off the straw in many directions. Thus, you should stand a safe distance from observers when conducting this demonstration.

Let me know if you fool your students!   

References 

1. http://pubs.acs.org/doi/pdf/10.1021/ed400578q
2. http://pubs.acs.org/doi/pdf/10.1021/ed076p1201
3. http://pubs.acs.org/doi/pdf/10.1021/ed100831p
4. https://en.wikipedia.org/wiki/File:Heat_of_Vaporization_(Benzene%2BAcetone%2BMethanol%2BWater).png The values cited above were taken at 300 K.

In a recent post, I shared sample quiz questions as to how I have differentiated assessment within the mole unit. Here, I will share a specific multi-day sequence within the stoichiometry unit. I have written extensively about the project that drives this unit (within the following blog posts: Why consider trying project based learning?, Backwards planning your PBL unit -­ An Overview of an Entire Unit and What ARE my students actually learning during this long term project (PBL)?), but very little about specific learning tasks. Below is a two day sequence of stoichiometry practice that I set up in my classroom. Stations are set up around the room and students rotate as necessary.

Brief unit context (elaborated upon in the links above surrounding the project): The first day of the unit, students are introduced to the Pharmaceutical Challenge- can they make 2.00 g of an assigned nutrient for a patient requiring IV nutrition? They have no idea what stoichiometry is (yet), but this gets them literally asking me to teach it to them.

After my students experience the entry event, they complete the Flinn POGIL activity on mole ratios. This activity uses analogies to get students thinking about relationships between numbers of items and mass, which leads to a definition of the mole ratio and a few simple exercises with mole ratios and maybe a mass to mole to mole relationship. Most of my students got the big ideas, but over the years I realized most kids needed a bit more scaffolding to take the leap to independent practice. So after the POGIL, we wrap up with a short lecture and work a few more examples together. In this lecture, I introduce before, change, after (BCA) tables as a scaffold - I have found it to be a very nice bridge that allows even struggling students to do stoichiometric calculations (here is a great post from Lauren Stewart describing use of BCA). My top students benefit because this thinking will support them in more challenging AP chemistry work down the line. Depending on the class, I do 2-3 sample problems as shown below. (Note: I used to get frustrated that I'd invest all of this time for my students to do a POGIL and still need to lecture. Sometimes guided inquiry is nice, sometimes it isn't. I'm choosy. However, for stoichiometry, I used to only lecture and would have to do a million lecture examples and kids on the by and by did not demonstrate they understood what was going on, even if they could memorize the mathematical steps. With the POGIL, kids are way more in tune with what's going on even though I still need to lecture a bit.)

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Then, students complete a mastery check (a self-graded mini-quiz to assess progress/mastery- this is mostly the provided POGIL check in with some tweaks).

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From there, I propose to students as to how they may proceed to get 1.5 hours (1.5 class periods) of solid “drill and kill” stoichiometry practice. You may have found in your practice that some students after doing a POGIL do not need any other sample problems, while others can follow the guided lecture practice but struggle to apply on their own. For me, it has been emotionally painful to watch the brightest students breeze through independent practice and not get challenged while, at the same time, trying to support students who get the basic logic but cannot apply the logic on their own without some support. Thus, this differentiated practice was born and honed over the course of a few years. Note the big question of the project, as well as these instructions, stay on the board the whole class period- even though I don’t make a big deal about the project, it is a reminder in the background that this is the purpose of all of the practice.

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There are five levels of practice. I push down the urge to micromanage this next part- student determine where to start. I give them a rough guide to use their mastery check- 100% or just small silly mistake? Start at level 3 or 4. Totally lost on the mastery check? Level 1. Got the basic idea but didn’t finish the mastery check? Start at level 2 or 3. However, this is a squishy description for me and I used to stress about students landing in the “right” place. Happily, for the most part, my agony was unfounded and students are, for the most part, challenged. [Interesting side-note/over-generalization: sometimes ladies choose a “level” lower than I think they should be, and boys choose a level “higher” than I would have assessed… not everyone, but some interesting cases.] Sometimes, if a student struggles for a LONG time, I might suggest moving down and then coming back to try again after a little more practice. It has never been a huge deal to ask a student to move.

As you peruse the practice problems, you will notice that level 1 is simply mole to mole practice. In level 2, I add  grams to mole and then mole to mole. Level 3 incorporates more units. Levels 4 and 5 are just fun problems that use mole ratios but require a bit more creativity and extrapolation of the basic ideas to solve.

My eight lab tables are roughly one-two for levels 1,4, and 5 and two- three for levels 2 and 3. There are labels and many copies of the corresponding practice set in a folder at the table. Here is a representative table label:

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When do students move to the next level? Students must check their work in a different color before checking in with me to record their progress in a spreadsheet. I can then ask questions about their annotations and use of BCA tables and such as I see fit.

What students see online is one succinct document shown below. Even though I print the blank practice problems, posting the originals is useful for students who are absent or want to work more at home (which does happen!).

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There is a whole-class incentive in addition to a personal incentive of a completion quiz grade (note: this is the ONLY completion quiz I ever use- that is the extent of my bribery to do a good job and it really works for the most part). The class chooses the incentive they work toward- the example class below chose for a few bonus points on their unit test, while other classes asked for bonus points on a project presentation or to drop the lowest quiz grade (for that last one, I upped the number of points needed as a class). Most classes meet the goal even if there are 1 or 2 absent students.

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What am I doing as students work? I am pacing the room, checking in individually with students or small groups of students for prodding, and just trying to encourage them to make progress and to keep pushing forward.

Finally, at the end of this practice work time, I force my students to take 15 minutes or so to gather their thoughts surrounding how this applies to their project at hand. The goal for this time isn’t so much to DO the math for their project than to summarize WHAT they will need to do.

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As I reiterate in almost every post, it has taken me years to build the flow and find problems that fit my students. This is a culmination of many things: my novice attempts at teaching with BCA tables, figuring out trouble points in their big old stoichiometry project, and more. Students still have an un-differentiated practice set before the unit exam, because in my mind, this still isn’t enough practice for all, but it’s a good start. Feel free to use this and try it in your classroom, or use this as inspiration to give your materials a remix. Thank you as always for your readership- it’s an honor to write for ChemEdX.

My first year teaching chemistry, I was looking for a soap-making lab or activity that I could run in my chemistry class with 25-30 students working at the same time. I usually do this activity right before spring break, as it provides enough time for the soap to harden and cure (high school students are impatient to use their soaps right away, which you should not do with cold process soap). I have used the activity at different points in the curriculum: during intermolecular forces, during acids and bases, and during stoichiometry. Although I know teachers who use soap making as a project during their stoichiometry unit, I chose to not emphasize the calculations as it would require more time than I have available. Simply making the soap easily fits in a 45-minute period.

I found the basic recipe from the blog “Reflections of a Science Teacher”¹, but I wanted to share how I have modified this procedure and other tips/tricks. I also provide students with background from a hot-process soap-making lab at Michigan State University². I thought that hot-process soap, while taking less time for the soap to be ready to use, was too complex and had too many safety concerns for me to use in my own classroom. So far, I have tried this activity for three years with two different recipes.

In a basic soap recipe, oils reacts with the sodium hydroxide (lye) to produce soap and glycerin. Most cold process soap recipes include “superfatting”, which simply means that the oil (the fat) is in excess to ensure that all of the sodium hydroxide is consumed.³ Both of the soap recipes that follow have 5% superfatting with reduced water (33% instead of 38%) because the recipes mostly use liquid oils, and I used an online calculator⁴ to check the amount of sodium hydroxide needed.

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Figure 1 - Pulling soap out of cup/mold.

The first recipe uses only olive oil and canola oil; this is the cheapest and easiest method to use. The original blog post referenced, Reflections of a Science Teacher, only olive oil; I chose to cut it with canola oil to reduce cost. A pure canola oil soap is also possible, but should be tested and the amount of lye required would need to be recalculated (there are plenty of lye calculators available online, such as SOAPCALC). The first recipe does not require the use of a hot plate to melt the oils. This soap takes a little longer to harden and should not be unmolded for at least two days.

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Figure 2 - Soap using coconut and olive oil.       Figure 3 - Soap using coconut and canola oil.

The second year I tried that we made soap in my course, I tried using olive oil, canola oil, and coconut oil. However, I found that the soaps were extremely soft. I wasn’t expecting this, as coconut oil usually produces harder soaps (as it is a solid at room temperature). I have not been able to find an explanation for this but I suspect that more glycerin is being formed, leaving the soap softer. Since then, I modified the second recipe to include only olive oil and coconut oil OR canola oil and coconut oil, and found that this recipe produces a nice hard soap that can be easily unmolded after a day of curing. The canola/coconut soap was also a little wet immediately after unmolding (see figure 1), but after a day or two of curing in air looked fine. A hot plate is required to melt the coconut oil before it is mixed with the liquid oil.

In either case, the soap must be emulsified properly before it can be poured into the molds (plastic cups). I have used two methods that both work well – students can either stir and then the teacher can use a stick/immersion blender to complete the emulsification, or students can mix the soap in a mason jar. With a stick blender, it takes about 1-2 minutes to reach trace. (“Trace” refers to the point in soap making that the oils and lye solution have emulsified and begins to thicken.⁵ In a tightly capped mason jar, 10-15 min of vigorous shaking will also completely emulsify the soap. I have usually done this lab before spring break, so the soaps will cure in the classroom for the week. Students can then unmold their soap when they return and wrap the soap in wax paper or place in a plastic bag to take it home. Technically, they should allow the soap to cure for at least another week before using the soap. This curing process allows excess water to evaporate and results in a harder soap. The pH of the soap will also continue to gradually decrease. The recommended curing time is 4-6 weeks for cold process soap. The longer the soap cures, the easier it will be to use, the longer the bar will last, and the gentler it will be on the skin.³ However, the soap should be safe to use after 2-3 weeks of curing.

If you choose to use this lab, I would recommend looking at the resources on Soap Queen³ (this is where I learned how to make soap at home). Note that “trace” for the soaps described here will be much less thick than the recipes on Soap Queen, particularly the version with only liquid oils. It really will look like vanilla cake batter. Also note that the students’ bars will be about half the size shown in the photos, because I just poured the entire batch into one cup when I was testing the recipe this year to see which would be the best to use. This past year, I used the first recipe because of its simplicity, but the olive oil/coconut oil recipe will produce the nicest soap. I have taken home the bars that I have made for samples and any of them are fine soaps to use for hand washing (I wouldn’t recommend them as a facial soap because they may be harsher than what we are used to). The longer the soaps sit before use, the harder they will be and the easier they will be to use.

An additional note: I have noticed that some students’ soaps remain very soft and sticky after a week and are almost like Playdoh, regardless of the recipe used. While I am still not sure why this happens, I suspect it has to do with how the oils and lye are mixed together. The softer soaps will harden properly after several weeks and are still safe to use.

Safety notes: I pre-weighed the sodium hydroxide so that students did not have to worry about directly handling solid sodium hydroxide. I suggest you set out the pre-measured NaOH in beakers, plastic cups or weigh boats (do not use paper cups since NaOH is highly hydroscopic). I also had students wearing safety aprons, but a strong lecture on the importance of safety before they start was sufficient to make them be careful. Having some vinegar on hand is a good idea as well, to deal with any spills. If students spill raw soap on their skin, they should quickly rinse with plenty of water. 

Also, the student resources include the following safety notes: 

• WEAR YOUR GOGGLES.
• Be very careful with the sodium hydroxide. If you spill any NaOH on your skin, rinse with water IMMEDIATELY and call your instructor.
• Be careful with the glass stir rod. If you are not gentle with it, it will break.

Over the past 30 years, numerous articles have been written about the importance of student teacher relationships. The National Education Association, NEA, offers advice for beginning teachers that includes establishing the classroom climate, conducting class efficiently, and reaching all students.¹ When teachers effectively connect to their students, discipline problems decrease and student engagement increases.^{2 3 4}

Teachers develop innovative ways to make connections and cultivate relationships. Some teachers’ writing assignments have students put themselves in the mindset of a character in a book or a historical figure. Other teachers spend hours decorating their classrooms to resemble Hogwarts or a Dr. Seuss book. Personally, I use my wardrobe.

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My collection of nerdy science shirts started innocently enough; my mother asked what I wanted for Chanukah, and I said that I wanted the “Heavy Metal” t-shirt from www.ThinkGeek.com. I could not have predicted that seven years later I would have accumulated a collection of about 60 nerdy science shirts. I also could not have predicted these silly nerdy science shirts would have become a part of my identity as a high school chemistry teacher.

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Like many teachers, I have a standard routine I use in my classroom. I begin with an opener, some sort of class activity, and try to conclude with a ticket to leave. On Fridays, however, I add an additional element into the class. After we discuss the opener, we always discuss my outfit. Why? Because every Friday I observe Nerdy Science Shirt Friday.

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What is Nerdy Science Shirt Friday? It is a holiday of my own invention where every Friday I wear a different nerdy shirt. My collection is large enough that I go through the entire school year without repeating a shirt. ]I try to match the t-shirt to something relevant to the students. Sometimes these shirts relate to the unit we are studying, other times, it relates to the school or secular calendar. For the first Friday of the school year, I often wear shirt from the XKCD comic: “Stand Back: I’m going to try science.” I choose this one because of the message it sends. Science is fun. Chemistry is fun. Science will not always be easy, but we are going to try and we are going to learn together. This shirt sets the tone to my students about how I am going to relate to them and how I am going to relate to chemistry. While I treat my students’ learning with great seriousness and care, we can laugh while we learn.

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Some of these shirts are terrible puns, as one student recently said “these are worse than dad jokes.” Others use the elements on the periodic table to spell words. Some have images of molecules or famous scientists. On the Friday my students practiced naming ionic compounds, I wore my shirt with iron(II) ions in a circle - a Ferrous Wheel. Mole Day is celebrated at work with the appropriate Mole shirt; but do not worry, when we get to the concept of the mole in class I have another one to wear. I proclaim the role of women in science with my shirts of Dr. Rosalind Franklin and Marie Curie. My ACS Green Chemistry shirt was the only appropriate shirt to wear for “Going Green” at Norfolk County Agricultural High School. While some teachers wear ugly holiday shirts in December, I choose one that says “Obey Gravity, It’s the Law” because Sir Isaac Newton was born on December 25. We rock on with a “heavy metals” shirt and “Le(a)d Zepplin.” We honor the “noble gases” and save the day with the “Chemical Avengers” On the Friday before the New England Patriots improbably won the Super Bowl, I, of course, had to wear my periodic table Boston shirt. When several of my students from the school where I previously taught asked me to come to their graduation and to hand them their diplomas, I wore a “graduated cylinder” shirt for them. They would not have had it any other way.

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These nerdy shirts enable me to bond with students, colleagues, and friends. One student, Trevor Ragas, wore his own geeky or nerdy science shirt almost every Friday we had class. Some students interrupt class to question me about my shirt if I had forgotten to explain it. Students, even those I did not teach, have reached out to me to let me know they loved and looked forward my shirts.

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Andrea Keith: “Your nerdy science shirts were the highlight of my Fridays! They always made me think, laugh, and contemplate buying my own if it was a really good one.”

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Macayla Paiva:“I LOVED your nerdy science shirts it made me look forward to having your class on Fridays and made me sad whenever our class skipped on Friday! They always made me laugh and realize just how many science puns can be made!”

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Shayla Shedin:“A lot of times they made us think about real world applications of the science we were learning in your class. It was great.”

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Meagan Audlee: “It was a good way to integrate learning and fun. It was something to look forward to each Friday. Each shirt would somehow connect with what we were learning.”

Darya Musatova: “Science and learning can be fun! It was something to look forward to and a great conversation starter. All knowledge and education starts with curiosity.”

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Though I have been observing Nerdy Science Shirt Friday in my classroom for several years, last year I expanded to celebrating it on social media by posting selfies on Facebook and tweeting them out. In doing so, I have started a trend. A business teacher and former colleague shares selfies of her geeky shirts every Friday. Recently graduated students commented “Finally nerdy shirt Friday” for the first Nerdy Shirt Friday of the school year and lamented how much they missed seeing my shirts in person on my Facebook page. Last April, a woman approached me in synagogue on a holiday and commented I was not appropriately dressed because it was Friday and I was supposed to be wearing a nerdy science shirt. Other chemistry teachers I only know through social media have begun sharing theirs as well. Friends often share with me shirts they think I should add to my collection, even if they are not school appropriate. Students have made me shirts I happily add to my collection.

My collection of nerdy science shirts have helped build lasting relationships with students, friends, and colleagues. Join me and others in observing #nerdytshirtfriday. And in case you don’t know where to start getting your shirts, I have found many at conference, museum shops and local stores, but I have also purchased shirts from the following places:

• Thinkgeek.com
• Woot.com
• 6dollarshirts 
• Neatorama.com
• teespring.com
• bustedtees.com
• teepublic.com

1. Zauber, K. Management Tips for New Teachers: Bringing Order to the Classroom (2003) Retrieved from http://www.nea.org/tools/management-tips-for-new-       teachers.html
2. Boynton, M and Christine Boynton (2005) Educator's Guide to Preventing and Solving Discipline Problems . Retrieved from http://www.ascd.org/publications/books/105124.aspx
3. Davis, H. A. (2003). Conceptualizing the Role and Influence of Student-Teacher Relationships on Childrens Social and Cognitive Development. Educational Psychologist,38(4), 207-234. doi:10.1207/s15326985ep3804_2
4. Sears, N. Building Relationships with Students. Retrieved from http://www.nea.org/tools/29469.htm

Acknowledgements:

Jacqueline Prester: Who challenged me to starting posting my Nerdy Science Shirts on Facebook and on Twitter.

To all my colleagues, friends, current and former students who have encouraged my observance of Nerdy Science Shirt Friday and have enabled my addiction by posting shirts that they think I should acquire.

I recently watched a video in which a chemist (who goes by the nickname “NurdRage”) activated a chemiluminescent reaction by vapor deposition. You can see a short clip of this experiment below:

Accessed at https://www.youtube.com/watch?time_continue=85&v=im_2OIs_mns (July 12, 2017)

Isn’t that cool? To create this effect, NurdRage soaked a card with a solvent containing hydrogen peroxide and a dye. He then opened a container of oxalyl chloride, (COCl)₂, which is quite volatile. As vapors of oxalyl chloride escaped the container, the oxalyl chloride dissolved into the fluid in the card and the following reaction occurred:

(COCl)₂ + H₂O₂à 2 HCl + 2 CO₂ + O₂

The chemical energy released in the reaction was gained by the dye in the card and released as light. Vapor activated chemiluminescence!

As soon as I saw this reaction I wanted to try it out for myself! Unfortunately, oxalyl chloride is toxic, corrosive, and a lachrymator. Thus, the experiment conducted by NurdRage needs to be conducted in a hood, and it is not particularly amenable to simple presentations. I began to wonder how I could create this vapor activated chemiluminescence using simple materials.

Luckily, I figured out how to create something similar to NurdRage’s experiment using just glow sticks, ammonia, filter paper, and plastic droppers. Here’s how it works. The reaction which provides energy to power glow sticks involves the base-catalyzed reaction between bis(trichlorophenyl oxalate) and hydrogen peroxide:

                                                                                                                                                       OH^-

C₁₄H₄Cl₆O₄ + H₂O₂à 2 C₆H₃Cl₃O + 2 CO₂

Ammonia is a base, so it can be used to catalyze the reaction that takes place in glow sticks. Ammonia also escapes aqueous solutions as a gas quite easily. Therefore, holding paper soaked in activated glow stick mixture above an opened bottle of ammonia should cause the glow stick mixture to emit more light! This is because the some of the ammonia vapors escaping the liquid will dissolve into the glow stick mixture, catalyze the reaction, and speed it up. Check out the video below to see how to carry out this experiment:

You will note that the experiment I conducted is an example of vapor catalyzed chemiluminescence in contrast to the vapor activated chemiluminescence achieved by NurdRage. Nevertheless, I think this experiment might be able to be used to show the effect of temperature on diffusion. For example, it might be interesting to try holding filter paper infused with glowing light stick mixture above ammonia that has been warmed and ammonia that has been cooled. Faster diffusion of ammonia out of the former should cause a greater increase in light emission than the latter. If you have any ideas on how to extend this experiment, be sure to share them with me. Happy experimenting!

Acknowledgement: My son, Jackson Kuntzleman, captured the film and helped to edit the video presented on the vapor catalyzed glow stick.