Evidence for the Effectiveness of Inquiry-Based, Particulate-Level Instruction on Conceptions of the Particulate Nature of Matter was published in the February 2012 issue of the Journal of Chemical Education. The authors, Chad Bridle and Ellen Yezierski, will lead off the ChemEd X Conference: Chemistry Instruction for the Next Generation with the first session. Bridle is a high school teacher in Michigan. He participated in the Target Inquiry Program at Grand Valley State University. Yezierski, now at Miami University, co-founded the program with Debbie Herrington. As the title of their article suggests, the authors focused on evaluating the effectiveness of several of the activities that were created by Bridle and other members of the cohort that focused on the particulate-level. 

If you register for the ChemEd X Conference:Chemistry Instruction for the Next Generation and attend Session #1, you can read the original JCE article, download the activities that are discussed in the article, find out what the authors have been doing since the article was published and engage in the conversation. 

The Conference opens on May 8th with an introduction from the organizers. The presentation for session #1 opens on this day as well. The session is open for discussion May 10 - May 12.

Are you familiar with the dynamic density bottle experiment? This interesting experiment was invented by Lynn Higgins, and is sold by various science supply companies.^1,2 Two immiscible liquids (usually salt water and isopropyl alcohol) and two different types of plastic pieces are contained within a dynamic density bottle. The plastic pieces display curious floating and sinking behavior when the bottle is shaken. Check it out in the video below:

The plastic pieces in the bottle have different densities. This difference, along with the different densities of the two liquids accounts for the differential floating and sinking behavior observed by the plastic pieces. Awhile back, I figured out how to make these bottles using simple household materials. I also figured out how to make the bottle work using LEGO pieces. LEGO pieces display sink-then-float behavior in a shaken density bottle. However, when two LEGO pieces are connected, an air pocket becomes trapped in between the two LEGO bricks. The trapped air confers a lower density to connected LEGO bricks as compared to unassembled LEGO bricks.

My students and I have continued to study the dynamic density bottle in a variety of ways. One thing we have done in particular is to figure out how to get the dynamic density bottle to work using unassembled LEGO blocks alone. In the video below you can see a bottle that works using only unconnected LEGO blocks:

Would you like to learn how we pulled this off? If so, consider joining Grazyna Zreda and me May 25 – 27^th during the “Chemistry Instruction for the Next Generation” online conference. During our session, we will be discussing this particular experiment. You can learn how to easily make your own dynamic density bottle. You can also learn how you can get the bottle to work using unconnected LEGO pieces. If you like colored chemistry experiments, you’ll certainly enjoy seeing how the two different liquids in the bottle can be differentially colored. Of course all of these activities will be connected to chemical principles such as intermolecular forces, density, solubility, and emulsions. Along the way, we’ll share several ides for inquiry-type investigations that you and your students can explore. After all, there’s almost always something new to learn about any chemical system.

Consider joining us, and be sure to check out all the other sessions that will be presented at this online conference. I hope to see you virtually during the conference!

References: 

1. https://www.flinnsci.com/salting-out---density-bottle-kit/ap7931/

2. https://www.teachersource.com/product/poly-density-kit/density

      Alchemie Animator By Alchemie, LLC is the latest creation from Julia Winter, CEO of Alchemie and the creator of the app Chairs. The free app is available in the itunes store and is currently designed for both iPhone and iPad.  I was told a computer version is in the works. This past week, I had the opportunity to participate in a live animator workshop hosted by Julia and saw some of the amazing things that are being done with this app. Next, I decided to check out YouTube to see what else Julia was doing with this app and what others were doing as well before I started brainstorming how else could I use this in my classroom.

     In the first video I saw by Julia entitled Methane Combustion, the animation looks at the combustion of methane to produce carbon dioxide and water.  

             The balanced equation is CH₄  +  2 O₂  --> CO₂  + 2H₂O  

I tried building this myself using the app as demonstrated in the video and it was relatively easy adding in each of the molecular substances and took very little time. I could easily see assigning this to my students to build. I thought this can be a great way to introduce balancing equations by having them build the molecular substances themselves and then later add in the bonds. We can also revisit again in the thermochemistry unit with making/breaking and bond energy. This could be useful in an AP class to check the molecular shapes as best as possible on a 2D plane. What was unique in this video is the fact that Julia builds the following:

 showing 2 CH₄ + 5O₂ --> ? CO₂  + ? H₂O  Since the ratio between the reactants is no longer 1:2 then something will be in excess. If you have been following some of the recent ChemEd X publications, you know a recent article, Using Visual BCA Tables to Teach Limiting Reactants by Melissa Hemling | Wed, 04/26/2017 mentions limiting reactants. Whether you calculate theoretical yield or the amount of excess reactant remaining is up to you. The topic of determining the limiting reactant and discussing why there may be some of both reactants remaining after the completion of the reaction is meaningful. Using the Alchemie animator may be an additional tool for helping your students build conceptual understanding. I myself have tested limiting reactants using particulate level drawings. This is another way to explain and show the topic of limiting reactants by allowing the students to move, manipulate, and then build the products of this methane reaction and discover for themselves what the actual yield is and what reactant is limiting and what is in excess. I have done this with my board magnets but now this allows every one of my students with the use of an iPad to do it themsleves.

As a result we see the following in the video,

 resulting in 2 CO₂ + 4 H₂O being produced with a single O₂ in excess and the two CH₄'s as the limiting reactant. If your students need another non-chemistry understanding then this clip is a favorite of mine from the movie Father of the Bride. See if you can figure out the correct combination for the superfluous buns and what is the correct ratio!

Next, in a previous post of my own, Building Molar Mass, 05/10/2015, I mentioned my use of different colored cubes to correctly build chemical formulas and then from that determine the substance's molar mass. I could see how the Alchemie app would be a great alternative instead of using the blocks. Similar to the blocks, the app allows for atoms to be different colors. Fifty two different colors to chose from to be exact. An advantage to the blocks is that with the text editor in the app a student can add in the chemical symbol on top of the circle and for an additional advantage they can add in the charges that are associated with each of the substances.  

In this example I built aluminum sulfate 

compared to with the blocks,

screen_shot_2017-05-08_at_12.29.26_am.png

Note: substances shown are those other than aluminum sulfate and later titles were added using text editing software. Again with the capability of adding in charges then oxidation and reduction reactions and assigning oxidation numbers to individual atoms can now easily be done with this app. There is even a built in template for building electrochemical cells. Now note that this application didn't require any animation but simply using the app to have the students build each of the chemical substances. Not that I would stop them, but the more advanced and familiar they become with the app then the more challenges you can introduce to them. Also, a nice feature with the app is that all work can be saved into files. Another nice feature is that the atoms can be made different sizes so if you wish to stress the size of metals versus the nonmetals or what happens to the size of an atom when it loses or gains electrons could easily be animated. Again, I have shown the diagrams to my students in the past regarding the size of an atom compared to its parent atom, but my feeling is that by building them and then adding animation allowing students to watch the sulfur atom become larger as it gains two electrons would be better than just seeing it via a diagram. Well, that's enough brainstorming for now. Other videos located on the Alchemie site include Boyles Law, an Aldol reaction, and even an electrochemical animation. Also, be sure to check out this video showing an example of the dissolving of table salt with Brittland DeKorver and other commentary by Michael Seery.

I first saw the Diet Coke and Mentos experiment during a science fair at an elementary school in 2005, and I was instantly hooked! To perform this experiment, Mentos candies are dropped into a bottle of carbonated beverage; Diet Coke tends to be the beverage of choice. In the video below you can see this experiment play out in slow motion. My son, John, captured the video from his second-story bedroom window:

The fountain results from the rapid formation and expansion of carbon dioxide gas bubbles in the beverage as a result of the addition of the candy. You have probably noticed bubbles of carbon dioxide form in the liquid any time a bottle of carbonated beverage is opened. However, the formation of these bubbles occurs very slowly because the activation energy for bubble formation in water is relatively high. The addition of Mentos candy to a carbonated beverage tremendously lowers this activation energy. That’s because pits and pockets on the surface of the Mentos candy, called nucleation sites, provide already-formed gas bubbles into which dissolved carbon dioxide can easily escape. Thus, adding Mentos candy to a carbonated beverage allows for rapid expansion of gas bubbles, which results in a fountain. You can watch this process in slow motion around a Mentos candy placed in a carbonated beverage in the video below:

In my opinion, Diet Coke and Mentos has all the hallmarks of a great science experiment for teachers and students: It is easy to set up and conduct, it can be accomplished using simple and familiar materials, it produces a dramatic and unexpected result, and it relates to a large number of physical and chemical concepts. It will come as no surprise to you that I have performed this experiment hundreds of times during class lectures, laboratory sessions, and demonstration shows (and also while just goofing around at home!)

Even better, I think this experiment provides a fantastic vehicle to involve students of all ages in small, hands-on and exploratory research projects. Like many others, my students and I have investigated various aspects of this interesting fountain. It’s fun, for example, to try this experiment with carbonated beverages that have been incubated at different temperatures:

Most recently, we looked into a curious phenomenon that we discovered: Fountains produced using flavored seltzer water (which contains water, dissolved carbon dioxide, and natural flavorings) go much, much higher than fountains produced using unflavored seltzer water (which contains water and dissolved carbon dioxide alone). Check it out:

Wow! That’s a big difference. The presence of natural flavorings causes an enormous effect on fountain height! It has been known for some time that the beverage additives aspartame and benzoate contribute to higher fountains, but we were quite surprised to learn that natural flavorings have the same effect. This led to several questions such as “how might natural flavorings lead to higher fountains?”, and, “what other substances might cause higher fountains?” So we began adding carefully measured amounts of all sorts of stuff to seltzer water: citric acid, sugars, alcohols, etc. By doing so we learned that we could dissolve just about anything in seltzer water to produce higher fountains, so long as enough of the material was added.

We also carefully looked at the bubble sizes formed during the experiment, and noticed that smaller bubbles formed when adding Mentos to carbonated water that contained dissolved materials. You can see this effect in the video below:

We worked on this for a while and were able to show a strong correlation between decreased bubble size and increased fountain heights in the Diet Coke and Mentos experiment. You can learn a lot more about our findings by checking out our article published in the Journal of Chemical Education or this infographic on the Compound Interest site. Both of these sources describe in more detail how smaller bubble size leads to higher fountains. The article also provides some suggestions for new and simple demonstrations that connect to the Diet Coke and Mentos experiment.

Speaking of new demonstrations, if you and your students have any suggestions for experiments to try, please let me know.  I’m always looking for new aspects of the Diet Coke and Mentos reaction to investigate, especially ones that can be explored in slow motion. Better yet, have your students get out there to try some experiments on their own and explain the results using chemistry!

Lasting Value and High Impact

The May 2017 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: project- and inquiry-based laboratories; measuring value and impact; research on core ideas and clickers; new twists on classic activities; understanding diffraction; acid-base chemistry; teaching informed by technology: flipped learning, biochemistry labs, and scientific computing for chemists; from the archives: chemistry helps feed the world.

Cover: Project- and Inquiry-Based Laboratories 

A recent transformation in the general chemistry laboratory courses at Michigan State University has yielded a series of project-based labs focused on the scientific and engineering practices from A Framework for K–12 Science Education. One such lab investigates the chemistry behind commercially available glow sticks. Shown on the cover are reaction mixtures with four different dyes before (top) and after (bottom) the addition of hydrogen peroxide, which drives the reaction. Dyes used (from left to right) are rhodamine B, rhodamine 6G, 9,10-bis(phenylethynyl)anthracene, and 9,10-diphenylanthracene. For further details see the laboratory experiment, A Glowing Recommendation: A Project-Based Cooperative Laboratory Activity To Promote Use of the Scientific and Engineering Practices, by Justin H. Carmel, Joseph S. Ward, and Melanie M. Cooper.

For additional inquiry-based labs in this issue, see:

Getting the Argument Started: A Variation on the Density Investigation ~ Joi P. Walker and Steven F. Wolf

Epoxidation with Possibilities: Discovering Stereochemistry in Organic Chemistry via Coupling Constants ~ Edward M. Treadwell, Zhiqing Yan, and Xiao Xiao

Measuring Value and Impact
Norbert J. Pienta and Marcy H. Towns discuss the metrics of Measuring Value and Real Impact of the Journal of Chemical Education. This topic is discussed in greater detail in: The Citation Index of Chemistry Education Research in the Journal of Chemical Education from 2008 to 2016: A Closer Look at the Impact Factor by Jon-Marc G. Rodriguez, Kinsey Bain, Alena Moon, Michael R. Mack, Brittland K. DeKorver, and Marcy H. Towns.

Research on Core Ideas and Clickers

Core Ideas and Topics: Building Up or Drilling Down? ~ Melanie M. Cooper, Lynmarie A. Posey, and Sonia M. Underwood (This article is available to non-subscribers as part of ACS Editors' Choice program.)

Chasm Crossed? Clicker Use in Postsecondary Chemistry Education ~ Rebecca E. Gibbons, Emily E. Laga, Jessica Leon, Sachel M. Villafañe, Marilyne Stains, Kristen Murphy, and Jeffrey R. Raker

New Twists on Classic Activities

New Demonstrations and New Insights on the Mechanism of the Candy-Cola Soda Geyser ~ Thomas S. Kuntzleman, Laura S. Davenport, Victoria I. Cothran, Jacob T. Kuntzleman, and Dean J. Campbell (Tom Kuntzleman discusses the background to this paper in his recent ChemEdX post, Exploring the Diet Coke and Mentos Experiment)

Using Silica Gel Cat Litter To Readily Demonstrate the Formation of Colorful Chemical Gardens ~ Masatada Matsuoka (To invistigate another chemical garden, try the "Magic Salt Crystal Garden" JCE Classroom Activity from the May 2000 issue of JCE.)

Understanding Diffraction

Teaching the Operating Principles of a Diffraction Grating Using a 3D-Printable Demonstration Kit ~ Paul A. E. Piunno

Quantum Interference: How To Measure the Wavelength of a Particle ~ Joseph M. Brom

Data Linearization Activity for Undergraduate Analytical Chemistry Lectures ~ James K. Harper and Emily C. Heider

Acid­-Base Chemistry

Acid–Base Poker: A Card Game Introducing the Concepts of Acid and Base at the College Level ~ Xuemei Zhang

Determining a Solubility Product Constant by Potentiometric Titration To Increase Students’ Conceptual Understanding of Potentiometry and Titrations ~ Lauren E. Grabowski and Scott R. Goode

Suggestion of a Viewpoint Change for the Classification Criteria of Redox Reactions ~ Seoung-Hey Paik, Sungki Kim, and Kihyang Kim

3-D Topo Surface Visualization of Acid–Base Species Distributions: Corner Buttes, Corner Pits, Curving Ridge Crests, and Dilution Plains ~Garon C. Smith and Md Mainul Hossain

Teaching Informed by Technology

Flipped Learning

Flipped Learning in Synchronously-Delivered, Geographically-Dispersed General Chemistry Classrooms ~ Michael A. Christiansen, Louis Nadelson, Lianna Etchberger, Marilyn Cuch, Trish A. Kingsford, and Leslie O. Woodward

Biochemistry Labs

iGUVs: Preparing Giant Unilamellar Vesicles with a Smartphone and Lipids Easily Extracted from Chicken Eggs ~ Víctor G. Almendro Vedia, Paolo Natale, Su Chen, Francisco Monroy, Véronique Rosilio, and Iván López-Montero

Green Fluorescent Protein-Focused Bioinformatics Laboratory Experiment Suitable for Undergraduates in Biochemistry Courses ~ Laura Rowe

Bring Your Own Device: A Digital Notebook for Undergraduate Biochemistry Laboratory Using a Free, Cross-Platform Application ~ Aaron R. Van Dyke and Jillian Smith-Carpenter

Scientific Computingfor Chemists

A Tractable Numerical Model for Exploring Nonadiabatic Quantum Dynamics ~Evan Camrud and Daniel B. Turner

Scientific Computing for Chemists: An Undergraduate Course in Simulations, Data Processing, and Visualization ~ Charles J. Weiss

From the Archives: Chemistry Helps Feed the World

Although Earth Day was celebrated in April, it's always timely to engage students with environmental chemistry. In keeping with the ACS's 2017 theme for Chemists Celebrate Earth Day, Chemistry Helps Feed the World, some ideas and suggestions for bringing environmental chemistry to students on agricultural and food chemistry, agrochemicals, and soil and water are available at ACS Axial.

Discover All the Value That JCE Has To Offer

With over 94 years of content from the Journal of Chemical Education available, you will always discover something useful—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 almost 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.

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.

Analyzing the Role of Science Practices in ACS Exam Items was published in the January 2017 issue of the Journal of Chemical Education. Tom Holme, a former ACS Exams Institute Director, authored the article along with Jessica Reed and Alexandra Brandriet. Their work considers how science practices have been incorporated into previously released ACS exams in the hopes of informing the creation of new assessment items that fit the expectations outlined by the NGSS.

If you register for the ChemEd X Conference: Chemistry Instruction for the Next Generation and the Session: Analyzing the Role of Science Practices in ACS Exam Items, you can read the JCE article and some additional notes offered by the authors. The session will be open for conversation May 15 - May 18. 

The College Board offers the opportunity to have access to guided inquiry "Building Block" performance tasks, "Building Block" digital assessments, and FRQ-style end of "Building Block" assessments directed specifically at nine "challenge areas." The "challenge areas" are organized according to the AP Chemistry six big ideas. I have used most of the resources available in AP Insight this year with my honors and AP chemistry students. Today, post-AP exam, I asked the students to provide me with feedback about the usefulness of those resources.

Student Evaluation of AP Insight Guided Inquiry Performance Tasks:

Question: Now that you've seen the AP exam, were the AP Insight guided inquiry packets helpful?

• "...The packets helped to train our minds to do the mental gymnastics College Board requires. They are good in a classroom setting, but are not enough on their own." (10th grade, male, AP Chemistry)
• "Yes. They were helpful. They taught the content with a higher level of thinking." (10th grade, male, AP Chemistry)
• "AP Insight was extremely helpful! It provided numerous examples and information that appeared similar to the exam (such as with diagrams) and helped me understand higher level concepts. (10th grade, female, AP Chemistry)
• "AP Insight on its own is not great, but if the teacher is capable of explaining the information in the packet well, then I think it is very helpful." (10th grade, male, AP Chemistry)
• "YES! They really mimicked the style of the exam. I felt comfortable with the style of the exam. I would use them as a teacher." (10th grade, female, AP Chemistry)
• "Independently, no. Without the teacher's aid and explanation, the AP Insight packets were kind of confusing and I wouldn't be able to complete the assignments." (10th grade, female, AP Chemistry)
• "...the packets were more difficult than the exam." (10th grade, female, AP Chemistry)

Student Evaluation of AP Insight Digital Quizzes:

Question: Now that you've seen the AP exam, were the AP Insight digital quizzes helpful?

• "The AP exam was nothing like the guided inquiry packets. The digital quizzes are worded just like the AP questions." (10th grade, female, AP Chemistry)
• "Yes, they were worded in the same way as the exam." (10th grade, female, AP Chemistry)
• "Yes, they gave me an idea of where I stood concerning the amount of information I understood and use to answer the questions. As a teacher, I would use them a lot." (10th grade, female, AP Chemistry)
• "They did help with multile choice and helped me understand wording and what they were asking." (10th grade, female, AP Chemistry)
• "I would use them if I were the teacher but not for a grade. I would probably use them as practice before tests or the exam." (10th grade, female, AP Chemistry)
• "I felt the questions were not like the questions on the AP test." (10th grade, female, AP Chemistry)
• "No, they just made me scared about the exam." (10th grade, female, AP Chemistry)

Student Evaluation of AP Insight FRQ-Style Challenge Area Assessments:

Question: Now that you've seen the AP exam, were the AP Insight FRQ-style challenge area assessments helpful?

• "There were very helpful. They always helped me understand/review the unit we were learning. I would use them to review the material, and I would discuss them in class if I were the teacher." (10th grade, female, AP Chemistry)
• "I loved the FRQ packets. They always took the material one step further which is excellent as the exam did the same. The AP exam focuses on harder topics. It expects you to learn the harder things and then throws completely new and even higher level thinking that doesn't seem possible. The questions did the same." (10th grade, female, AP Chemistry)
• "YES.  They were almost the same in the way they were set up/worded." (10th grade, female, AP Chemistry)
• "They were waaaaay harder than the AP exam." (10th grade, female, AP Chemistry) 
• "They summarized the unit well." (10th grade, male, AP Chemistry)

In summary, my students overwhelming report "AP Insight: Chemistry" is useful in preparation for the AP Chemistry exam. I guess we'll see in July if their scores support the claims.

For your information, here are the challenge areas addressed with the program.

• Big Idea 1: Structure of Matter
  • Challenge Area: Evaluate Scientific Models for Atomic Structure
• Big Idea 2: Properties of Matter
  • Challenge Area: Connect IMFs and Physical Properties
  • Challenge Area: Explain Chemical Bonds
• Big Idea 4: Rates of Chemical Reactions
  • Challenge Area: Evaluate Reaction Mechanisms and Rate Data
• Big Idea 5:
  • Challenge Area: Connect Changes in H, S, and G to K
  • Challenge Area: Represent and Model Energy
• Big Idea 6:
  • Challenge Area: Explain Equilibrium
  • Challenge Area: Relate Equilibrium Concepts to Acids and Bases
  • Challenge Area: Explain Buffer Systems

Erica Posthuma-Adams answered the Call for Contributions for the Journal of Chemical Education's Advanced Placement Chemistry Special Issue with her article, How the Chemistry Modeling Curriculum Engages Students in Seven Practices Outlined by the College Board. Erica has been using Modeling Instruction pedagogy for some time now. She serves as a workshop leader helping others learn about the pedagogy and is a member of the board of the American Modeling Teachers Association. In her presentation for the Chemistry Instruction for the Next Generation Conference, we will consider her JCE article. She also points attendees to three of the articles she wrote for ChemEd X. 

If you have not been attending the conference, you can still register for free. 

This session, highlighting How the Chemistry Modeling Curriculum Engages Students in Seven Practices Outlined by the College Board, will be open for conversation May 18 - 20. Be sure to choose the ATTEND button on the session to receive notifications and engage in the conversation. You can also follow the conversation on Twitter using #cexccingsess3.

When describing abstract concepts like chemical bonding, it always seems to feel far too easy for both teachers and students to resort to the “wants” and “needs” of atoms. After all, we understand what it means to want, need, or like something, so it often feels appropriate (and easier) to use a relatable metaphor or subtly anthropomorphize these atoms to accommodate our students’ current reasoning abilities. While predicting the types of bonds that will form and the general idea behind how atoms bond can be answered correctly using such relatable phrases or ideas, the elephant in the room still remains—do our students really understand why these atoms bond? 

The following explanation should feel rather familiar.

“Since chlorine wants 1 electron and sodium wants to lose 1 electron, chlorine will steal sodium’s 1 valence electron so that they both have a full outer shell and are stable.”

I don’t know about you but that feels awfully familiar to me and it’s not too difficult to realize why. I was taught that way, I taught it that way, my students learned it that way from me, and my students explained it that way to me for years. It wasn’t until a colleague of mine shared a great JChemEd article,¹ which focused on placing a greater emphasis on the electrostatic interactions in chemical bonding, that I started to really question the depth of understanding on this topic that I was expecting from my students. 

So for the first time ever in my career, I decided to pump the brakes on the wants and needs of atoms and instead focus more on the electrostatic interactions between atoms to account for chemical bonding. Much of this new approach was centered on a topic we had recently learned—electronegativity. However, I started to notice this whole idea of electronegativity difference wasn’t sitting so well with a significant portion of my students. It became obvious to me that many of them had just simply memorized the consequence of what would happen if one atom had a significantly larger electronegativity than another. For example, they might say that because fluorine’s electronegativity is so much larger than sodium’s, fluorine will end up taking sodium’s valence electron. Statements like this bothered me because they didn’t convince me that the student actually knew what was taking place. 

To satisfy this uncomfortable feeling, I proposed to them the following two scenarios that I knew couldn’t be correctly answered unless they understood what was going on at a conceptual level. 

Scenario 1:  If atom X has an electronegativity of 3.6 and atom Z has an electronegativity of 1.2, draw vectors to represent the attractive and repulsive forces present between the atoms.

Scenario 2: Using your understanding of attraction, provide an explanation for why phosphorus (P) and chlorine (Cl) form a covalent bond instead of an ionic bond.

In short, the majority of my students couldn’t accurately represent the attractive/repulsive forces present in the diagram. They would do things like draw a vector displaying that atom X was being pulled on by atom Z with more force or that the repulsive vectors were actually larger than the attractive vectors, which wasn’t accurate for the situation provided. In addition, for scenario 2, the vast majority of them resorted to explanations like “phosphorus is a nonmetal and chlorine is a nonmetal, so they form a covalent bond” or “the difference in electronegativity between phosphorus and chlorine is 0.9, which falls within the window of being polar covalent, so that’s why they don’t form an ionic bond.”

In order to deepen their understanding, I needed to take a different approach. That’s when a colleague of mine, Erica Posthuma (@eposthuma), told me about Seth Furlow’s (@Furlow_teach) video which modeled the idea of ionic bonding using film canisters, magnets, and washers in a way that I had never seen before.

It was then that I started to use phrases like “pull strength” or “strong/weak positive core” to account for electron transfer. In addition, I had shared the magnets and washers idea with a colleague in my department and that same day, he quickly assembled some old prescription pill bottles, magnets, and washers so that I could have my own items to model the concept with my students whenever I wanted. 

Having these pill bottles and magnets at my disposal completely changed everything for many of my students. There were numerous times when students would be struggling to understand something about this topic and I would sit right next to them and model it in front of their eyes. A typical conversation would look something like this.

Me: Ok, check this out.  I’ve got these two pill bottles and you see the one washer that appears to be stuck to one of the bottles?

Student: Yea

Me: Ok, well watch what happens when I slowly bring them together.

Once the pill bottles are close enough, the washer all of a sudden leaps from one bottle to the other.  Since I didn’t tell the students about the magnets ahead of time and they can’t see them, they are usually really surprised and it’s clear that they didn’t expect that to occur.

Me: So what happened?

Student: That pill bottle took the washer away from the other bottle. 

Me: Why do you think that happened?

Student: Do you have magnets under there or something? 

Me: Yea, I do. That explains why the washer was stuck to the original bottle and why it’s stuck to the new bottle. But why did the washer switch bottles?

Student: The magnet in that bottle (new bottle) must be stronger than the other magnet in the original bottle.

Me: True, I have a much stronger magnet in here.  But why does having a stronger magnet matter?

Student: Because the stronger magnet will pull on it with a greater force than the other magnet.

Me: Exactly. So why do you think sodium’s 1 valence electron transfers to chlorine without using the term electronegativity?

Student: Chlorine must pull on sodium’s valence electron with a greater force than sodium does.

Me: Awesome. So would you say that it appears as though sodium wants to give its electron up or that fluorine really wants an electron?

Student: Well….no, not really wants. I guess it’s more about whatever happens to pull with a greater force.

I must have had 15-20 conversations like this, which would not have taken place if I didn’t have the models with me. Sometimes I would even tell them to do it and allow them to literally feel the attractive force building until the washer transfer was made. From then on, I saw many more explanations centered on “pull strength” and forces to account for electron transfer or lack thereof. 

Not only did this open a new pathway for me to communicate an idea but it effectively allowed my students to visualize an abstract concept in a way that was far less likely to lead to a misconception or weak understanding due to oversimplification. 

I highly encourage you to make your own models!  All you will need are the following materials:

1. Film canisters (or pill bottles)
2. 2 magnets of different strength.  I attached 2 small neodynium magnets* together for the stronger magnet.
3. Glue or tape to keep the magnets attached to the inside of the canister lid.
4. 1 or 2 small metal washers.  

Thank you to Erica Posthuma (@eposthuma...You can also follow her ChemEd X blog) for giving me the idea in the first place and to Seth Furlow (@Furlow_teach) for making the video and allowing the idea to spread!

*I purchased my neodynium magnets from Amazon. The link provides several options.

¹ Venkataraman, B. Emphasizing the Significance of Electrostatic Interactions in Chemical Bonding. J. Chem. Educ. 2017, 94, 296−303.

What are we doing to help kids achieve?

     I tend to enjoy acid base titrations for several reasons.  First, students get to work with burettes, acids, bases and they see a nice "color change" when they reach an endpoint. Many times, students who tend to struggle with pen and paper testing excel at the "hands-on" approach. Titrations also dovetail well with stoichiometry which provides a nice review of information closer to the end of the year.

     This year in one of my classes we just did not have the chance to set up the burettes, standardized the base and find the concentration of the unknown acid. Instead, we went to "plan B". Everything was changed to microscale. Students first started titrating 1 M HCl with 1 M NaOH. Each time they just "counted drops" and because it was microscale they did multiple trials while checking multiple indicators to see which was the best.  Next, they had to solve for the concentration of the unknown HCl solution. I did a simple dilution on some of the bottles and just placed blue painters tape over the old labels. The unknown took just a few minutes to create.  Students could easily do multiple trials in a small amount of time. They also were able to count the drops required to form 1 mL of fluid and this lead to conversion factors. There was no broken glassware.

We also had time to add a titration. This involved solving for the percent of vinegar in acetic acid and then checking with the USDA's requirements for mustard and comparing answers. Most students were successful with the experiments. It also lead to allowing students to run their own experiments with less use of chemicals.

    Should this always be the way to go? Probably not. Students who are going on in chemistry probably should have the exposure with burettes. Should a teacher feel "bad" or "guilty" if he or she does not get to the burettes? That depends...are we teaching the students to be chemists or to think like chemists? I would suggest the latter. Both large scale and microscale have advantages and drawbacks. In an ideal world it would be great to always be able to put the experiments in the hands of the students with the best equipment possible...but if for whatever reason we can't, there is no shame in going to "plan B". Have you found a "plan B" that works better than you thought?  Don't be afraid to share...I would love to hear about it and I would bet so would others.  As an aside, most students had a 5% error when solving for the amount of vinegar in mustard just by counting the drops.......

It might be the case that today's blog post is a bit off-topic from my traditional blog posts. It's a bit of a personal narrative, and I hope that's OK.

You see, today is 21st May, 2017 and this date represents the anniversary of my dad passing away. And that is significant because my dad was my role model. He was an environmental chemist working for the State of Washington Department of Ecology for many years, including my time as a chemistry major at university. I would occasionally visit his lab and observe him "on the bench" as he called it. There is no doubt in my mind that my interactions with him played a big role in my choosing chemistry as a major - despite zero pressure from him to follow in his footsteps. I can say, though, that he beamed with joy at my graduation ceremony when he got to meet many of my chemistry professors.

My first teaching job was in Los Angeles, California. As a young teacher, I was full of enthusiasm and energy - but I lacked the nuanced style of the veteran teachers around me. Each day was a new experience full of challenges; I loved every minute of my time in front of the classroom. And luckily for me, I still love being a teacher. I can't think of anything more important - or rewarding! - to call my career.

Recently I was chatting with a friend about my time in Los Angeles and I recalled a story I would like to share. My dad came down to Los Angeles to visit me for a few days. And being a chemist, he joined me in the classroom. The lesson plan for the day involved calculating the number of waters of hydration in copper (II) sulfate pentahydrate. I would say this is a "classic" lab where the students heat a sample of the hydrated crystal until it is dry. They use the masses involved to calculate a mole ratio and determine the number of waters of hydration. Below are a few pictures from a recreation I set up today.

My dad loved being there with me and interacting with my students. He was working with one lab group that was finished, and in his gentle manner he said to the group, "Add a couple drops of water to your crystals." And so they did, observing something like what you will see in the video below.
 

Needless to say, in my world as a newbie chemistry teacher I never would have thought of having my students re-hydrate the crystals. Of course the response from the students was immediate and very vocal. "Cool!""Woah, what happened?" As word spread to the surrounding groups, my dad was called over by each of the remaining groups to show them the source of all the hubbub. I just stood back and smiled, learning a little something along the way. I now look for places where I can make connections between concepts. For example, with the rehydration the concept of reversible reactions comes into play. So often students think of reactions as a one-way street and this reaction is a nice reminder that this is simply not always the case. And of course the reaction is quite exothermic - so there is another connection to exploit. And colors of transition metal ions can be linked here as well. 

And now, over 20 years later, every time I rehydrate anhydrous copper II sulfate I think of my dad. And my smile becomes a bit bigger.

Who was your inspiration to become a teacher?

And what seemingly simple ideas did you overlook early in your career that you rely on now?

The 4^th session of the ChemEd X Conference highlights the Journal of Chemical Education article, Collaborative Professional Development in Chemistry Education Research: Bridging the Gap between Research and Practice. The article outlines the collaboration of a group of instructors from many levels of education led by Professor Hannah Sevian. The discussion runs through May 24^th. #cexccingsess4

Session #5 of the ChemEd X Conference, Chemistry Instruction for the Next Generation, highlights the Journal of Chemical Education article, Nature or Naughty: Bringing “Deflategate” to the High School Chemistry Classroom. Elizabeth Megonigal is a high school teacher and her activity is designed to provide real context to the chemistry content in her classroom. The session will be open for conversation May 24 – 26.

You can follow the conversation on Twitter using #cexccingsess5.

Session #6 of our ChemEd X Conference: Chemistry Instruction for the Next Generation highlights the Journal of Chemical Education article, The Dynamic Density Bottle: A Make-and-Take, Guided Inquiry Activity on Density. The author, Tom Kuntzleman, is presenting this session along with high school teacher, Grazyna Zreda. Kuntzleman and Zreda connected on Twitter and collaborated to extend the ideas shared in the original article. Kuntzleman published some of those extensions in ChemEd X posts that are highlighted in the presentation as well.

Session #6 will be open for conversation May 25 – 27. You can follow the discussion on Twitter using #cexccingsess6.

The inaugural ChemEdX Conference: Chemistry Instruction for the Next Generation is wrapping up this week. The first session was based on a Journal of Chemical Education article, “Evidence for the Effectiveness of Inquiry-Based, Particulate-Level Instruction on Conceptions of the Particulate Nature of Matter”, authored by Chad Bridle (Grandville HS, Grandville, MI) and Ellen Yezierski (Miami University, Oxford, OH). (This is an ACS Author’s Choice article, meaning that you can access it for free without a subscription to JCE.) This was great timing for me because my freshmen classes were just beginning to learn about physical properties and changes and I have used the “Change You Can Believe In” inquiry-based activity for several semesters now. In this blog post, I want to share how I incorporate the Target Inquiry activity for the first part of the unit.

On Day 1, I write out a flowchart for students to emulate to help define pure and impure substances; element, compounds, and mixtures; and homogeneous and heterogeneous mixtures. It looks similar to the following and I include definitions along with it.

matter_flowchart.jpg

Next, I introduce solutions and describe the difference between solute and solvent. I provide examples of solutions with varying states of matter (dependent on solvent state). My favorite example is a wet diaper since I have two daughters under age 2 at home. Kids might be grossed out until I get my “Instant Snow Polymer” out that I purchased at an NSTA conference years ago. “Instant Snow Polymer” is comprised of sodium polyacrylate (active ingredient in diapers) and it can expand to 40 times its original volume when water is added. Students love this demo, especially when they volunteer! 

By day 2, we begin a discussion of the states of matter and students work through the pre-lab portion of “Change You Can Believe In.” We discuss how one should approach particulate models and talk about their significance.

Day 3 and 4 consist of the “Change You Can Believe In” activity where students are tasked with understanding, describing, and demonstrating the differences between physical and chemical changes in the form of particulate level models. Here are some examples of the particulate models students look at:

change_you_can_believe_in_a.jpg

change_you_can_believe_in_b.jpg

change_you_can_believe_in_e.jpg

change_you_can_believe_in_h.jpg

Sample cards from the "Change You Can Believe In" activity.

We wrap up Part 1 of the unit by learning about gas laws (qualitative aspect) and the difference between heat and temperature (using the “Incredible Ice Melting Blocks” demo). Students often believe that ice will melt faster on the warmer block or at equal rates. Last semester and this semester I decided to give students an assessment halfway through the unit and then cover phase changes separately. In doing so this semester, I contacted Chad Bridle for example assessment questions that included more particulate models. I had been reflecting and realized that even though we were using them in class, I wasn’t assessing students with the models; this had to change because I have found that using particulate models within the assessments helps me better evaluate my student's conceptual understanding. 

Lots of educational research shows that the most effective learning occurs when the teacher and learner are both engaged, and communication occurs in both directions. Unfortunately, the most widely-used educational practice involves a monologue, wherein a single speaker provides information to an audience of passive listeners. In “A Global Warming Primer”, Jeffrey Bennett provides a different template for conversation about the most pressing global environmental issue of our time. His approach harkens back to a tradition of religious education, the “catechism”. A catechism is a prescribed exchange of questions and answers intended to indoctrinate children or converts, teaching them the tenets of the faith. The questions are predetermined by the church and the answers are intended to be accepted and preferably memorized by the learner. The catechism is the same as it was last year as it was a couple of hundred years ago. This doesn’t work that well in science, where the questions arise in the mind of the inquirer and the answers are based on data and reason. Acceptable answers can change over time, as more data is collected and models interpreting them evolve and improve.   

Bennett’s little (hundred page) and inexpensive book anticipates the questions that would likely arise in the mind of a student or a person skeptical that climate change is real or that it is caused by human activity. His question-and-answer book addresses all of the Big Questions: How do we know the climate is changing? How do we know that the changes are largely caused by humans? Is there anything we can do about it? The seventy-some questions in the Primer are organized in four sections: The Basic Science, The Skeptic Debate, The Expected Consequences, and The Solution. The result is a very convincing, understandable explanation of the problem.  In my opinion, the best part is the extensive use of graphs, maps, cartoons, and photographs that help to show “How do we know that?” Another terrific resource for presentations about climate change is the great ACS Climate Science Toolkit on the Web: https://www.acs.org/content/acs/en/climatescience.html, which I enthusiastically recommend.

      Alchemie Animator By Alchemie, LLC is the latest creation from Julia Winter, CEO of Alchemie and the creator of the app Chairs. The free app is available in the itunes store and is currently designed for both iPhone and iPad.  I was told a computer version is in the works. This past week, I had the opportunity to participate in a live animator workshop hosted by Julia and saw some of the amazing things that are being done with this app. Next, I decided to check out YouTube to see what else Julia was doing with this app and what others were doing as well before I started brainstorming how else could I use this in my classroom.

     In the first video I saw by Julia entitled Methane Combustion, the animation looks at the combustion of methane to produce carbon dioxide and water.  

             The balanced equation is CH₄  +  2 O₂  --> CO₂  + 2H₂O  

I tried building this myself using the app as demonstrated in the video and it was relatively easy adding in each of the molecular substances and took very little time. I could easily see assigning this to my students to build. I thought this can be a great way to introduce balancing equations by having them build the molecular substances themselves and then later add in the bonds. We can also revisit again in the thermochemistry unit with making/breaking and bond energy. This could be useful in an AP class to check the molecular shapes as best as possible on a 2D plane. What was unique in this video is the fact that Julia builds the following:

 showing 2 CH₄ + 5O₂ --> ? CO₂  + ? H₂O  Since the ratio between the reactants is no longer 1:2 then something will be in excess. If you have been following some of the recent ChemEd X publications, you know a recent article, Using Visual BCA Tables to Teach Limiting Reactants by Melissa Hemling | Wed, 04/26/2017 mentions limiting reactants. Whether you calculate theoretical yield or the amount of excess reactant remaining is up to you. The topic of determining the limiting reactant and discussing why there may be some of both reactants remaining after the completion of the reaction is meaningful. Using the Alchemie animator may be an additional tool for helping your students build conceptual understanding. I myself have tested limiting reactants using particulate level drawings. This is another way to explain and show the topic of limiting reactants by allowing the students to move, manipulate, and then build the products of this methane reaction and discover for themselves what the actual yield is and what reactant is limiting and what is in excess. I have done this with my board magnets but now this allows every one of my students with the use of an iPad to do it themsleves.

As a result we see the following in the video,

 resulting in 2 CO₂ + 4 H₂O being produced with a single O₂ in excess and the two CH₄'s as the limiting reactant. If your students need another non-chemistry understanding then this clip is a favorite of mine from the movie Father of the Bride. See if you can figure out the correct combination for the superfluous buns and what is the correct ratio!

Next, in a previous post of my own, Building Molar Mass, 05/10/2015, I mentioned my use of different colored cubes to correctly build chemical formulas and then from that determine the substance's molar mass. I could see how the Alchemie app would be a great alternative instead of using the blocks. Similar to the blocks, the app allows for atoms to be different colors. Fifty two different colors to chose from to be exact. An advantage to the blocks is that with the text editor in the app a student can add in the chemical symbol on top of the circle and for an additional advantage they can add in the charges that are associated with each of the substances.  

In this example I built aluminum sulfate 

compared to with the blocks,

screen_shot_2017-05-08_at_12.29.26_am.png

Note: substances shown are those other than aluminum sulfate and later titles were added using text editing software. Again with the capability of adding in charges then oxidation and reduction reactions and assigning oxidation numbers to individual atoms can now easily be done with this app. There is even a built in template for building electrochemical cells. Now note that this application didn't require any animation but simply using the app to have the students build each of the chemical substances. Not that I would stop them, but the more advanced and familiar they become with the app then the more challenges you can introduce to them. Also, a nice feature with the app is that all work can be saved into files. Another nice feature is that the atoms can be made different sizes so if you wish to stress the size of metals versus the nonmetals or what happens to the size of an atom when it loses or gains electrons could easily be animated. Again, I have shown the diagrams to my students in the past regarding the size of an atom compared to its parent atom, but my feeling is that by building them and then adding animation allowing students to watch the sulfur atom become larger as it gains two electrons would be better than just seeing it via a diagram. Well, that's enough brainstorming for now. Other videos located on the Alchemie site include Boyles Law, an Aldol reaction, and even an electrochemical animation. Also, be sure to check out this video showing an example of the dissolving of table salt with Brittland DeKorver and other commentary by Michael Seery.

I first saw the Diet Coke and Mentos experiment during a science fair at an elementary school in 2005, and I was instantly hooked! To perform this experiment, Mentos candies are dropped into a bottle of carbonated beverage; Diet Coke tends to be the beverage of choice. In the video below you can see this experiment play out in slow motion. My son, John, captured the video from his second-story bedroom window:

The fountain results from the rapid formation and expansion of carbon dioxide gas bubbles in the beverage as a result of the addition of the candy. You have probably noticed bubbles of carbon dioxide form in the liquid any time a bottle of carbonated beverage is opened. However, the formation of these bubbles occurs very slowly because the activation energy for bubble formation in water is relatively high. The addition of Mentos candy to a carbonated beverage tremendously lowers this activation energy. That’s because pits and pockets on the surface of the Mentos candy, called nucleation sites, provide already-formed gas bubbles into which dissolved carbon dioxide can easily escape. Thus, adding Mentos candy to a carbonated beverage allows for rapid expansion of gas bubbles, which results in a fountain. You can watch this process in slow motion around a Mentos candy placed in a carbonated beverage in the video below:

In my opinion, Diet Coke and Mentos has all the hallmarks of a great science experiment for teachers and students: It is easy to set up and conduct, it can be accomplished using simple and familiar materials, it produces a dramatic and unexpected result, and it relates to a large number of physical and chemical concepts. It will come as no surprise to you that I have performed this experiment hundreds of times during class lectures, laboratory sessions, and demonstration shows (and also while just goofing around at home!)

Even better, I think this experiment provides a fantastic vehicle to involve students of all ages in small, hands-on and exploratory research projects. Like many others, my students and I have investigated various aspects of this interesting fountain. It’s fun, for example, to try this experiment with carbonated beverages that have been incubated at different temperatures:

Most recently, we looked into a curious phenomenon that we discovered: Fountains produced using flavored seltzer water (which contains water, dissolved carbon dioxide, and natural flavorings) go much, much higher than fountains produced using unflavored seltzer water (which contains water and dissolved carbon dioxide alone). Check it out:

Wow! That’s a big difference. The presence of natural flavorings causes an enormous effect on fountain height! It has been known for some time that the beverage additives aspartame and benzoate contribute to higher fountains, but we were quite surprised to learn that natural flavorings have the same effect. This led to several questions such as “how might natural flavorings lead to higher fountains?”, and, “what other substances might cause higher fountains?” So we began adding carefully measured amounts of all sorts of stuff to seltzer water: citric acid, sugars, alcohols, etc. By doing so we learned that we could dissolve just about anything in seltzer water to produce higher fountains, so long as enough of the material was added.

We also carefully looked at the bubble sizes formed during the experiment, and noticed that smaller bubbles formed when adding Mentos to carbonated water that contained dissolved materials. You can see this effect in the video below:

We worked on this for a while and were able to show a strong correlation between decreased bubble size and increased fountain heights in the Diet Coke and Mentos experiment. You can learn a lot more about our findings by checking out our article published in the Journal of Chemical Education or this infographic on the Compound Interest site. Both of these sources describe in more detail how smaller bubble size leads to higher fountains. The article also provides some suggestions for new and simple demonstrations that connect to the Diet Coke and Mentos experiment.

Speaking of new demonstrations, if you and your students have any suggestions for experiments to try, please let me know.  I’m always looking for new aspects of the Diet Coke and Mentos reaction to investigate, especially ones that can be explored in slow motion. Better yet, have your students get out there to try some experiments on their own and explain the results using chemistry!

Lasting Value and High Impact

The May 2017 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: project- and inquiry-based laboratories; measuring value and impact; research on core ideas and clickers; new twists on classic activities; understanding diffraction; acid-base chemistry; teaching informed by technology: flipped learning, biochemistry labs, and scientific computing for chemists; from the archives: chemistry helps feed the world.

Cover: Project- and Inquiry-Based Laboratories 

A recent transformation in the general chemistry laboratory courses at Michigan State University has yielded a series of project-based labs focused on the scientific and engineering practices from A Framework for K–12 Science Education. One such lab investigates the chemistry behind commercially available glow sticks. Shown on the cover are reaction mixtures with four different dyes before (top) and after (bottom) the addition of hydrogen peroxide, which drives the reaction. Dyes used (from left to right) are rhodamine B, rhodamine 6G, 9,10-bis(phenylethynyl)anthracene, and 9,10-diphenylanthracene. For further details see the laboratory experiment, A Glowing Recommendation: A Project-Based Cooperative Laboratory Activity To Promote Use of the Scientific and Engineering Practices, by Justin H. Carmel, Joseph S. Ward, and Melanie M. Cooper.

For additional inquiry-based labs in this issue, see:

Getting the Argument Started: A Variation on the Density Investigation ~ Joi P. Walker and Steven F. Wolf

Epoxidation with Possibilities: Discovering Stereochemistry in Organic Chemistry via Coupling Constants ~ Edward M. Treadwell, Zhiqing Yan, and Xiao Xiao

Measuring Value and Impact
Norbert J. Pienta and Marcy H. Towns discuss the metrics of Measuring Value and Real Impact of the Journal of Chemical Education. This topic is discussed in greater detail in: The Citation Index of Chemistry Education Research in the Journal of Chemical Education from 2008 to 2016: A Closer Look at the Impact Factor by Jon-Marc G. Rodriguez, Kinsey Bain, Alena Moon, Michael R. Mack, Brittland K. DeKorver, and Marcy H. Towns.

Research on Core Ideas and Clickers

Core Ideas and Topics: Building Up or Drilling Down? ~ Melanie M. Cooper, Lynmarie A. Posey, and Sonia M. Underwood (This article is available to non-subscribers as part of ACS Editors' Choice program.)

Chasm Crossed? Clicker Use in Postsecondary Chemistry Education ~ Rebecca E. Gibbons, Emily E. Laga, Jessica Leon, Sachel M. Villafañe, Marilyne Stains, Kristen Murphy, and Jeffrey R. Raker

New Twists on Classic Activities

New Demonstrations and New Insights on the Mechanism of the Candy-Cola Soda Geyser ~ Thomas S. Kuntzleman, Laura S. Davenport, Victoria I. Cothran, Jacob T. Kuntzleman, and Dean J. Campbell (Tom Kuntzleman discusses the background to this paper in his recent ChemEdX post, Exploring the Diet Coke and Mentos Experiment)

Using Silica Gel Cat Litter To Readily Demonstrate the Formation of Colorful Chemical Gardens ~ Masatada Matsuoka (To invistigate another chemical garden, try the "Magic Salt Crystal Garden" JCE Classroom Activity from the May 2000 issue of JCE.)

Understanding Diffraction

Teaching the Operating Principles of a Diffraction Grating Using a 3D-Printable Demonstration Kit ~ Paul A. E. Piunno

Quantum Interference: How To Measure the Wavelength of a Particle ~ Joseph M. Brom

Data Linearization Activity for Undergraduate Analytical Chemistry Lectures ~ James K. Harper and Emily C. Heider

Acid­-Base Chemistry

Acid–Base Poker: A Card Game Introducing the Concepts of Acid and Base at the College Level ~ Xuemei Zhang

Determining a Solubility Product Constant by Potentiometric Titration To Increase Students’ Conceptual Understanding of Potentiometry and Titrations ~ Lauren E. Grabowski and Scott R. Goode

Suggestion of a Viewpoint Change for the Classification Criteria of Redox Reactions ~ Seoung-Hey Paik, Sungki Kim, and Kihyang Kim

3-D Topo Surface Visualization of Acid–Base Species Distributions: Corner Buttes, Corner Pits, Curving Ridge Crests, and Dilution Plains ~Garon C. Smith and Md Mainul Hossain

Teaching Informed by Technology

Flipped Learning

Flipped Learning in Synchronously-Delivered, Geographically-Dispersed General Chemistry Classrooms ~ Michael A. Christiansen, Louis Nadelson, Lianna Etchberger, Marilyn Cuch, Trish A. Kingsford, and Leslie O. Woodward

Biochemistry Labs

iGUVs: Preparing Giant Unilamellar Vesicles with a Smartphone and Lipids Easily Extracted from Chicken Eggs ~ Víctor G. Almendro Vedia, Paolo Natale, Su Chen, Francisco Monroy, Véronique Rosilio, and Iván López-Montero

Green Fluorescent Protein-Focused Bioinformatics Laboratory Experiment Suitable for Undergraduates in Biochemistry Courses ~ Laura Rowe

Bring Your Own Device: A Digital Notebook for Undergraduate Biochemistry Laboratory Using a Free, Cross-Platform Application ~ Aaron R. Van Dyke and Jillian Smith-Carpenter

Scientific Computingfor Chemists

A Tractable Numerical Model for Exploring Nonadiabatic Quantum Dynamics ~Evan Camrud and Daniel B. Turner

Scientific Computing for Chemists: An Undergraduate Course in Simulations, Data Processing, and Visualization ~ Charles J. Weiss

From the Archives: Chemistry Helps Feed the World

Although Earth Day was celebrated in April, it's always timely to engage students with environmental chemistry. In keeping with the ACS's 2017 theme for Chemists Celebrate Earth Day, Chemistry Helps Feed the World, some ideas and suggestions for bringing environmental chemistry to students on agricultural and food chemistry, agrochemicals, and soil and water are available at ACS Axial.

Discover All the Value That JCE Has To Offer

With over 94 years of content from the Journal of Chemical Education available, you will always discover something useful—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 almost 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.