I always find this time of year quite harrowing. I am right in the middle of academic competition season with Olympiads in physics, chemistry, biology, and math. I have science bowl and ocean bowl along with bridge building all on the same day. Why do we do this to ourselves?

Well I have some idea about why especially when it comes to Chemistry Olympiad. I have never been as motivated as I am when I am trying to prepare my kids for this event. I like teaching AP Chemistry but I do find that the syllabus makes me follow a pretty specific set of topics and the questions are going to come from that set of topics. Many people might jump all over that statement but I am not trying to start an argument. I am just saying we pretty well know what is going to be asked. Chemistry Olympiad is different. There are a really good number of surprises that pop up and over the past three or four years it has expanded nicely.

I know that my inner city students with very weak backgrounds in all skill areas are going to be challenged by this exam. They will not have the skills to just read Zumdahl once and get a good score. I have to work with them and train them to “think different” as Steve Jobs was famous for saying. I am teaching extra lectures now just focusing on material that is fair game on chemistry Olympiad and not likely to be on the AP exam. We are having a great deal of fun covering biochemistry, quantum mechanics, radiation, organic, simultaneous equilibriums, unit cells, complex ions, and transition metal chemistry. I am running laboratories that I do not do with my AP class and these labs last longer. How am I getting this done?

My kids have convinced me to run an after school program to accomplish this. Since it is after school anyone who wants to come is allowed in and not one student gets a grade. This relieves much of the everyday pressure kids experience. Students from other chemistry classes and even other schools are in attendance. I get so excited for this every week that I don’t care I am not getting paid for it. There may be teachers that will accuse me of being a martyr because I offer this time without pay. I am just trying to get a chance to teach some cool chemistry and enjoy it while I can. Each Friday I am getting about 35 kids dropping in for this class. Mostly it is the same kids each week but it changes from time to time. I have been running it for three years now and last year one of the most exciting aspects started to develop. Other teachers from the school began to join us.

I love team teaching. I have done it for years including a weekend course at UCLA I teach with two of the best chemistry teachers in the area. We love lecturing together and are always chiming in on each others explanations. Now I am getting to do this with one of the teachers from my own school. The best part might even be that she is British. Every time we go into something new she ends up saying “well when I taught in London we did this… or that” the kids absolutely love hearing this very different approach, different lab, and different style to the subject matter.

To me it is amazing how much energy I can have on a Friday afternoon! These events provide me with a different outlet and I get to work with other teachers I really enjoy working with.

About three years ago I had an idea.

I thought it would be fun to build a new Chemistry elective around the science of food. I floated the idea by some colleagues and students and everyone agreed; a Food Chemistry course could be an interesting and fun class for students looking for an advanced Chemistry course, but who weren’t necessarily interested in going the AP route. Encouraged by the positive responses, I set out to research and collect resources as I played around with how to structure the class content. Working in an Independent School, I am afforded a lot of freedom when designing the classes I teach. This freedom is both invigorating and terrifying. As I began to sketch out what I wanted the class to be I realized I could make this class anything I wanted! I wasn’t tied to any framework or state standards!

WAIT!?! THERE IS NO FRAMEWORK OR STATE STANDARDS!?! How will I know what to include? Where will I find activities and assessments? Who will I turn to when I inevitably get in over my head? How will I teach food science without a food-safe lab?

When the initial panic wore off, I turned to my tried and true source for teacher collaboration, Twitter. (Want to learn more about using Twitter for collaboration? Check out Lowell Thomson’s article) Of course, I found some brilliant and generous teachers who were willing to share their thoughts with me. Three different teachers from across the country tweeted at me and said they were willing to join in a conversation. We started a google doc and each of us contributed the ideas and resources we had collected over the years. Dana Hsi (@wwndtd), Kathryn Ribay (@kathrynribay), and Jason Olson (@jasonleeolson) graciously compiled the items they had collected, and engaged in thoughtful dialog on the best ways to introduce food science to high school students. The document we created would launch dozens of google searches and lead me down hours of food-themed YouTube rabbit holes.

After the google doc collaboration, I searched through the archives of the Journal of Chemical Education and came across two articles describing collegiate Food Chemistry courses designed for non-majors. The articles, “Science of Food and Cooking: A Non-Science Major Course” by Deon T. Miles and Jennifer K. Bachman and “Design of a Food-Chemistry Themed Course for Nonscience Majors” by Patrice Bell helped me piece together the framework that would become my class. I also attended two Food Chemistry Mini-Workshops at the Biennial Conference on Chemical Education (BCCE) in 2014 and 2016. (These workshops were organized by Elizabeth Pollock from Stockton College, Subha Das from Carnegie-Mellon University, and Sunil Malapati from Clark University) The BCCE experience showed me I could teach food science outside of a kitchen lab and I walked away with a new set of activities for my class. Instead of a traditional textbook, I have been pulling additional ideas and activities from three books I had on my shelf. What Einstein Told His Cook by Robert Wolke, What Einstein Told his Cook 2 by Robert Wolke and Marlene Parrish, and On Food and Cooking by Harold McGhee. I am also using YouTube videos from ACS Reactions and SciShow, as well as episodes of Good Eats with Alton Brown. After playing around with different formats, I decided to structure the course around food molecules. I plan to include four main units: Water, Lipids, Carbohydrates, and Proteins.

My first unit, Water, is outlined below:

Learning Goal(s) C.1.1 Properties of Water Describe the properties of water and implications to food science.

• I can qualitatively and quantitatively describe the properties of water such as polarity, solubility, vapor pressure, boiling point, and freezing point.
• I can quantitatively describe concentration of solutions.
• I can differentiate between solutions, colloids, suspensions, and emulsions - and discuss their applications to food science.

I began the class by reviewing the properties of the water molecule, namely polarity. I used the SciShow video, Does Water Go Stale Overnight? to engage the class in a discussion about tap water. We then discussed factors affecting solubility and colligative properties. My students practiced doing concentration calculations and conceptually explaining the process of solvation. I challenged them answer the question, “Does water boil at the same temperature in the microwave as it does on the stovetop?” They had to design an investigation to answer the question and collect data at home, then report back to the class. To finish out the first week I found a recipe for rock candy for the students to try over the weekend.

The following week we began a study of caffeine. I showed ACS Reactions videos, Caffeine: The World’s Most Popular Drug and Why Does Coffee Make you Poop? followed by SciShow’s Caffeine! The students then conducted a solvent extraction of caffeine in the laboratory. In the lab activity students learned a new procedure, solvent extraction, and were able to apply what they had learned about solubility from the previous week.

In the final week of the unit, we discussed emulsions, suspensions, and colloids. I introduced the terms in a brief lecture and then had the students break into small groups to practice making a foam and an emulsion. I gave each group an egg, a bowl, and a whisk. We used three types of bowls, stainless steel, plastic, and glass. The first challenge was separating the yolk from the white. Once each group had an egg white, they set aside the yolk and started whisking. I came around and added a different substance to each bowl. Students experimented with the effects of vinegar, tartaric acid, citric acid, baking powder, and lemon juice. They compared their results with the other groups. We discussed how the material the bowl was made of affected the foam and how the different add-ins changed the consistency of the egg white. We then moved on to the egg yolk and attempted to make an emulsion. They began whisking and added a small amount of vinegar. Some groups were instructed to add a cup of vegetable oil all at once, and some were told to drizzle it in. The results were distinctly different. The students then started offering ideas on why some foams worked better than others and why some emulsions failed, when others were successful. The next day we watched Season 1 Episode 10 of Good Eats entitled "The Mayo Clinic" and Alton Brown explained the science behind a successful mayonnaise emulsion. The students were challenged to make a mayonnaise at home, and include at least one “add-in” they thought would enhance the flavor. They wrote lab reports including their materials and procedure. 

Chem 101 is a FREE (for a limited time) app for any apple or android device designed to improve engagement in college chemistry courses. Although the intended audience is college level, there are modules appropriate for high school as well. Students can use the app to practice on their own, or instructors can create in-class or at home assignments. Topics included in the app are:

• Simple Lewis Structures
• Structures with Multiple Central Elements
• Formal Charge and Polyatomic Ions
• Exceptions to the Octet Rule
• Resonance Structures
• Electron Domain and Molecular Geometries
• Hybridization
• Sigma and Pi Bonds
• Molecular Polarity
• Conceptual Questions

The interface is user friendly, with fluid graphics and in app tools to help students visualize the relationship between Lewis structures and molecular shape. According to Justin Weinberg, CEO of 101:

• Chem101 was used by 2,000 students across 8 schools in Fall 2016 including Carnegie Mellon, Columbia University, and the University of Cincinnati.

• 40% of students said using Chem101 made them more interested in chemistry after using the product for just 2-3 weeks of the curriculum

• 77% said they preferred Chem101 over existing course tools, i.e. clickers

• Students who learned Lewis structures using Chem101 performed up to 200% better compared to those who used traditional learning tools (based on pre and post-semester testing)

I’m very excited to start using this in my classroom.  Learn more and download the app from www.101edu.co/.  

If you have read much of my past work here on ChemEd X, you know I am a big proponent of using Twitter for professional development. I owe many of my current teacher practices to my fellow chemistry teachers from around the world.

In December I got a Tweet from @Meachteach mentioning a book titled, "Argument-Driven Inquiry" and he reflected on his first experience using the book and the Claim Evidence Reasoning (CER) framework. Needless to say, I was intrigued. (Honest note: I haven't bought the book yet, but it's on my birthday Wish List!) But in reading through Ben's ideas, I was inspired to try using the CER framework with my own students. I have been looking for a way to add some depth to my students' lab experiences and this framework looked promising.

More recently, Ben published a detailed blog "Implementing the Claims, Evidence, Reasoning Framework in the Chemistry Classroom" about his use of the CER framework. That information sets up my own reflection in this post of using the framework for the past two months quite well.

My First Experience Using CER 

I modified a gas laws lab I have used with the Vernier pressure sensors for a few years by adding some details to reflect the CER framework. The lab investigates four relationships: pressure and volume; pressure and temperature; volume and temperature; and pressure and number of molecules. Typically I assign separate groups to handle different tasks and then present their findings to the class. Two years ago my directions were pretty simplistic. "Be ready to present next class." Last year I went a bit further and created the following expectation:

DATA ANALYSIS

1. Create organized data tables for your section of the lab.

2. Create a graph for your section of the lab that clearly shows the relationship being studied.  Use your own data for these graphs.

3. For your part of the experiment, write an equation using the two variables and a proportionality constant, k (e.g., for Part I, P = k ´ V if direct, or P = k/V if inverse).

With your group, create a whiteboard (or series of whiteboards) to show each of the following.

After all the data is collected and the whiteboards have been written, we will have a “Board Meeting” where groups will share their results and their whiteboards. I will take pictures of all of the whiteboards and share them in the Topic 1 Google Drive Folder.

This certainly helped, as it created some good discussion. But what was lacking from this was an explanation of the relationship being studied. Therefore, based on idea I had learned from Ben, I modified the lab again to include the following Data Analysis:

DATA ANALYSIS

With your group, create a whiteboard (or series of whiteboards) to show each of the following.

Your “Claim” is essentially the conclusion based on your data.

Your “Evidence” is your data and a GRAPH of your data. You should also include an equation that models your system. [For example, write an equation using the two variables and a proportionality constant, k. (e.g., for Part I, P = kV if direct, or P = k/V if inverse.)]

Your “Reasoning” is an explanation of the evidence. Why is this relationship valid? Include some particle-level discussion and diagrams.

After all the data is collected and the whiteboards have been written, we will have a “Board Meeting” where groups will share their results and their whiteboards.

I will take pictures of all of the whiteboards and share them in the Topic 1 Google Drive Folder.

Unfortunately, I was absent at a conference when the "Board Meetings" would take place. So I had students video their meetings. Due to the privacy policy of my school, I am not able to share these videos. However, I will say they were informative. I learned a lot about how the students processed the ideas. But I wasn't there to push their thinking with questions. So I was looking for another venue for the CER framework.

My Second Experience Using CER

In his ChemEd X blog post, Ben discusses the idea of when and how to use the CER Framework:

#2 - Is this only for lab reports or can I use this for homework, quizzes, tests, presentations, etc. too?

The answer to this can be whatever you want it to be. During my 1st year of implementation, I only used CER in the lab setting. I regret that decision because the nature of our content provides opportunities for students to practice and reflect on their scientific explanations pretty much daily. Adhering only to the lab setting may allow students to think that somehow their explanations of findings in the lab have a fundamentally different structure than the answers I ask them to provide on an assessment. This year, for the first time, I have started to incorporate CER into my quizzes, tests, labs, and homework.

I would like to respond directly to that idea, because the second attempt at CER did not involve a lab. We were in the middle of our Energetics unit (Topics 5 and 15 for the IB Syllabus). While studying enthalpy of hydration I normally present some data and ask students to draw a conclusion and "be ready to discuss next class" within my video lesson on enthalpy of hydration. I did that the same this year as I had done before. But instead of a standard class discussion, I organized my students into groups and had them work through the data using the CER framework. The question posed was, "What factors affect the enthalpy of hydration for ions?"

Below is the set of directions given:

Question

What factors affect enthalpies of hydration for ions?

Directions

Use the data below to generate at least two claims relating to factors affecting enthalpies of hydration for ions.

Generate a Whiteboard with four sections:

• Question

• Claim

• Evidence

• Reasoning

Note that your evidence should include one or more graphs. You can create one whiteboard per claim, or put multiple claims on the same whiteboard. 

Note: The data provided here comes from your textbook. Consider alternative sources of data for your graphs. (Translation: To be really effective at providing evidence, you will need data that is not provided here.

I won't go into the chemistry here, but the patterns are typically quite obvious to the students. The difference with this year's attempt at this discussion is the attention given to focused evidence that directly supports the claim(s) made and reasoning that links the evidence to the claim, providing a plausible "mechanism" (for lack of a better word) for the trend. In my mind, this is one of the great benefits of this framework: Evidence only works if it directly supports the claim. This forced my students to really evaluate the quality of their graphs (as you can see below). I can imagine that with more practice using this framework, their explanations will improve. 

Below are some student-generated whiteboards. Since I wasn't present for the first attempt, as mentioned, I really considered these my first chance to give feedback on the spot to the students and actually modify any misconceptions. The discussions were quite robust, with students asking clarifying questions as well. I will admit, though, that by the last group we had heard just about all we could hear about the topic at this level and the activity stagnated a bit. I can only imagine that with the gas laws lab this would not have happened as there were four different relationships to discuss.

Just yesterday we were discussing a lab related to Hess's Law and evaluating an error associated with leaving solid sodium hydroxide on the lab counter for a few minutes before dissolving it. I asked the students to make a claim about the error and how it would affect the results. They then had to provide some evidence and reasoning about the claim. It wasn't "perfect" CER, but having used the framework with them just last week I found that it helped the students give a bit more depth to their evaluation.

Ben is hosting a Webinar through AMTA about CER on February 22, 2017. Given the time difference with UTC + 7 for me in Bangkok I'm not yet sure if I can join, but I'm hopeful! I hope that he will continue to share more of his expertise with us at ChemEd X as well. 

Have you implemented  CER or any similar framework to help discussions? I would love to hear about it.

What are we doing to help kids achieve?

     This summer at BCCE 16 George Lisensky and Emma Koenig from Beloit College presented a workshop on how to use LED lights to demonstrate periodic properties. They designed a lab for college students and presented the ideas and theories to teachers (these are the slides they presented). I must admit, I have a love affair with all things periodic table and I had never seen this idea. I was excited to try to develop a version of what they did for high school students.

     Here is the idea behind the lab. First, students need to understand how LED lights work. Essentially, every LED light has a "band gap". Electrons are pushed into an empty orbital which is negative and then the positive end of the circuit attracts the electrons. As they go down in energy through the band gap, they emit light. The larger the band gap, the more energy, the smaller the wavelength and the closer to the "blue" end of the spectrum. So, the key is to try to control the band gap and thus control the color of light. As it turns out, the carbon family is the perfect group of elements to use because of the crystal lattice structure.  There is only one problem...the band gaps are either too large or small and emit light that cannot be seen. Scientists decided then to make "solid solutions" of elements on either the right (boron family) or left (nitrogen family) of the carbon family. These solid solutions were developed so that on average, elements have four valence electrons similar to the carbon family.

     So....as an example, here is the composition of two LED lights. One light is a solid solution that is composed of GaP_1.00As_0.00 and the other one is composed of GaP_0.40As_0.60. The way these are interpreted is that there is Gallium which is in the Boron family and there is a mix of Phosphorus and Arsenic from the Nitrogen family. There is one part Gallium and one part Phosporous in even amounts in the first LED light with no Arsenic. In the second LED light there is a "solid solution" made up of 1 part Gallium, .4 parts Phosphorus and .6 parts Arsenic. The key is that the ratio of the Boron and Nitrogen family constituents are 1 to 1 but within that ratio, there may be different amounts of elements in the same family such as .4 parts Phosphorus and .6 parts Arsenic as compared to 1 part Phosphorus and 0 parts Arsenic.

     Here is where the periodic table comes into play....in general, the greater the ionization energy and the greater the electronegativity, the larger the band gap and the higher energy photons. Students can examine the two lights mentioned. In general a solid solution that has more gallium and more phosphorus and no arsenic has more atoms with a higher electronegativity and ionization energy than a solid solution with the same amount of gallium but .4 parts Phosphorus and .6 parts Arsenic. Therefore, the first LED light would have a larger band gap and light closer to the blue end of the spectrum. In fact, this LED light is green. The second light composed of elements that overall have a lower ionization energy and electronegativity compared to the first have a smaller band gap with less energy and photons closer to the red end of the spectrum. This light is red.

    At the high school level we first had to cover trends in the periodic table. Next, I assigned students to create a one page "infographic" that answered two questions. How do LED lights work and why do they have different colors? Finally I provided them with six LED lights in which they were given the compositions and had to predict the wavelengths from "shortest" to "longest". They first had to develop a theory and then test only two of the lights. They then had the chance to keep their theory or change it based on the test and then they could test all six lights.

     For a first time activity, it went well but there were a few rough spots. Some students just googled the compositions to try to predict the colors. I told them that the prediction was only a small portion of the problem. They had to come up with the "why" and explain it to me. The best part of the activity was when two of my smartest students tested the first two lights and their predictions were proven wrong. We talked through it and they came to the conclusion that they confused the band gap idea. They thought that a smaller band gap would produce light on the blue end of the spectrum. Once they re-examined their results they figured out the problem and corrected it...with little guidance from me.  

     Overall, this was a good activity on several levels. It did take some time to order the LED lights and set up the power sources. It is my hope to have the finished activity posted in this site in the activity section in the future. Do you have a novel and unique lab or activity that your kids get excited about? Why not share? I look forward to hearing from you.

I would like to thank Dr. George Lisensky and his student, Emma Koenig, of Beloit College, Beloit, WI for their 2016 BCCE presentation. I received permission from Dr. Lisensky by e-mail to use the materials from their presentation.

In an effort to better understand my high school students' knowledge of what is happening during phase changes, heating curve calculations, and the ever popular can crush demo, I run them through a series of activities. First, I ask my students "What Temperature Does Water Boil At? This is in reference to the same question mentioned in the infographic What Temperature Does Water Boil At? by Compound Interest.

What Temperature Does Water Boil At? Compound Interest Infographic

We discuss the importance of atmospheric pressure and how that relates to changes in a substances boiling point. This is then followed by boiling water at room temperature in a bell jar with a vacuum pump and of course then using the vacuum pump to run several other demos. 

Second, with a class set of iPads, I have them view the heating curve activity from AACT. It is a members only simulation activity but the diagram can be found in most chemistry textbooks or on line if you search heating curve of water.  

heating curve AACT

Heating Curve Simulation - AACT Solutions

We discuss the flat lines found on the graph during the phase changes and why on the side of a box of Hamburger Helper the cooking times are different if you live at high altitudes. Third, I run my students through the calculations associated with specific heat of ice vs water vs steam and the Heat of Fusion and Vaporization during the phase changes. The simulation allows us to check our answers. However, what was really unique about using the AACT simulation was that as we clicked on the parts of the graph we saw a visual representation on the particulate level of what the water looks like at that location marked in the boxes as T₁ and T₂. As you can see below, water is depicted as a single circle, but what my students noticed was the so called "trail lines" that were associated with the circles. My students quickly understood that the greater the number of trail lines means that the particles are moving faster. We noticed that some of the circles in the same pictures had the same number of lines but some were shorter than others. Students understood this to mean that not all particles in the same phase are moving with the same amount of energy. I don't know if that was intended, however it got the concept across so I was excited to see where this would go next.

Particle level representation found on the AACT Heating Curve Simulation.

Lastly, I performed the can crush demo for my students. I wanted them to describe what was happening on the particulate level as the little amount of water inside was heating up and then quickly condensing as the can was inverted into the water.. By using a desktop camera to simply project the image of the can before and after crushing on a magnetic board without the screen pulled down I asked my students to represent what was happening on a particle level during each part of the demo using magnets, colored markers, water molecule models, or snatoms. I was fascinated that many of the classes included those "trail marks" that they had seen previously in the simulation we had used. Other groups used arrows like I have seen used in Modeling Instruction. I have included several pictures representing the activity and some of the representations my students created. I invite you to comment or ask questions below.

Using Snatoms on the projection of the AACT simulation heating curve.

If you have never used the CAN CRUSH demo, check out Steve Spangler's Can Crusher video and directions.

This week, one of my students alerted me to some mobile apps featuring chemistry. One, in particular, seems to be mostly free and incorporates a hands-on approach to conducting virtual laboratory experiments. The app is called BEAKER - Mix Chemicals and is offered by THIX on the Apple and Google Play Stores. My student demonstrated how the app works and I gotta say - it's pretty sleek. 

According to the developer, "you can hold it, shake it, heat it up, cap it, add in chemicals, pour out, or pour between BEAKERS via AirMix." AirMix allows two phones running BEAKERS to wirelessly pour liquid from one BEAKER into another if in close proximity. Furthermore, the developer includes the opportunity to test 300+ reactions using 150 chemicals. This might be worth checking out if your classes have limited lab time or capability.

The developer has 2 additional mobile apps available: Chemist and Space.

In this post I’ll be sharing a bit about the chemistry of the Berry food color found in McCormick’s Color from Nature food coloring. I will also describe some experiments and demonstrations that can be done using this food color. This post is the second in a three-part series in which the chemistry of McCormick’s Color from Nature food dyes are described. In Part 1 of the series, we explored Sky Blue food dye. A box of McCormick’s Color from Nature food dyes contains three packets of dyes: Sky Blue, Berry (red) and Sunflower.

The Berry food color is intended to impart a red color to foods. The ingredients list for the Berry food coloring lists “beet juice color”, and this is likely the component responsible for the bright red color observed when Berry dye is dissolved in water.

1 Betanin is an acid base indicator, displaying various shades of red and violet at different pH values. I added the McCormick berry dye to buffers at pH 2, 4, 7, 10, 12, and 14. Upon doing so, I noticed the dyetook on a red color at pH 2 – 7, and a purple color at pH 10 – 12. At pH 14, the colorant changed yellow.

Chemical structure of betanin

Figure 1: Chemical structure of betanin, the main pigment in beet juice color.

The pK_a values reported for the various acidic protons on betanin² (Figure 1) and the fact that betanin is cleaved to the yellow betalamic acid at high pH³ are fairly consistent with these observations. I also noticed that the Berry dye lost its color upon addition of Cu²⁺ ions. This is consistent with the fact that betanin oxidizes quite easily in the presence of oxygen in a process that is sped up by the addition of metal ions.⁴ Finally, the berry dye dissolves well in water but not acetone, consistent with the charged nature of betanin. You can watch some experiments I carried out with the Berry dye in the video below.

Like the Sky Blue dye, it is easy to obtain the absorption spectrum of the Berry dye dissolved in water (Figure 2). As I expected, the absorption spectrum observed is similar to the absorption spectrum of betanin.

Absorption spectrum of berry dye

Figure 2: Absorption spectrum of Berry food dye in water

I spent quite a bit of time in stores trying to find commercial products that contained beet juice color. Specifically, I looked for beverages that contained this dye. Interestingly, I could only find dairy products which contained beet juice color. I suspect that this is because betanin degrades easily upon exposure to light.^3,6 Thus, betanin-containing beet juice color would be amenable as a dye for foods that are opaque (or enclosed in opaque packaging), which would limit exposure to light. Indeed, dairy foods tend to have these characteristics. As an interesting side note, I did purchase one bottle of strawberry milk that listed red beet juice color as an ingredient. When I opened the bottle to observe the contents I expected to see pink colored milk, but it was completely white. I think this observation might indicative the beet juice color in the milk was oxidized. This is in line with the reported ease with which betanin is degraded under various conditions.

Please let me know any interesting observations you make if you try out any experiments with the Berry food dye or foods that contain beet juice color. I look forward to hearing from you. Happy experimenting!

References:

1. Gandia-Herrero, F.; Simon-Carillo, A.; Escribano, J.; Garcia-Carmona, F. J. Chem. Educ.2012, 89, 660 – 664. 

2. Gliszczynska-Swiglo, A.; Szymusiak, H.; Malinowska, P. Food Additives and Contaminants2006, 23, 1079-1087.

3. Reshmi, S. K.; Aravindhan, K. M.; Suganya Devi, P. Asian Journal of Pharmaceutical and Clinical Research 2012, 5, 107-110.

4. Wybraniec, S.; Starzak, K.; Skopińska, A.; Szaleniec, M.; Słupski, J.; Mitka, K.; Kowalski, P.;  Michałowski, T. Food Sci. Biotechnol. 2013, 22, 353-363.

5. Harmer, R. A. Food Chemistry1980, 5, 81 – 90.

6. http://yadda.icm.edu.pl/yadda/element/bwmeta1.element.baztech-695f9783-a...

After spending the start of the year using a modified version of the Modeling Instruction curriculum (density and physical properties, followed by gas laws, followed by energy and phase changes), we don’t actually start talking about what’s inside atoms until December. I love that by this point students are already familiar with some of the habits of mind needed to reason abstractly about atoms -- thinking proportionally, explaining macroscopic observations at the particle level -- and we are ready to layer on both more abstraction and the symbolic level. By January, we are ready to explore electron configurations.

The seventh grade science teacher at my school does a great job introducing students to fundamentals like protons, neutrons, and electrons, the general structure of the Bohr model, and using the periodic table to find valence electrons. By the time students reach my class in 10th grade, I want to elevate their work beyond the memorization and application of patterns and into a deeper thinking process.

Inspired by the inimitable Kelly O’Shea, I introduced students to the word “epistemology” this year. I tried to frame it not as a dry, required vocabulary term that must be memorized, but as an exciting project with some snazzy vocab: how do we know what we know about atoms?

To get students to think about not just what electrons are present but where they are, and the fact that they are different, I adapted some materials from POGIL and the Modeling Instruction curriculum. First, students explore a POGIL¹ on coulombic attraction to determine the major factors that affect the force of attraction between protons and electrons: distance and quantity. The next day, students applied this to data about ionization energy, trying to figure out how the ionization energy (a proxy for force of coulombic attraction) can give insight into the positions of electrons. In small groups with guiding questions, they start to uncover that a high ionization energy must indicate electrons that are close to the nucleus, and that the different groups of electrons they see in the data must reflect different positions. (This also nicely coincides with students’ work with piecewise functions in Algebra II.)

It’s really cool to see the moment when students connect the energy data to the Bohr model diagrams they encountered in middle school, and to recognize that models come from evidence, not just out of the blue. It’s even cooler when some of them realize (independently!) that the subtle patterns in the data indicate limitations to that model. These limitations lead us into studying the s, p, d, and f subshells and a more detailed form of electron configuration.

Before last year, I never even tried to teach anything beyond the Bohr model in detail. (I never tried to teach the term epistemology, either!) But once I started using this data-driven approach to electrons, I got hooked. Don’t get me wrong -- this hasn’t been the easiest shift. I’m still seeking more hands-on and lab activities to go along with this work. In my co-taught classroom, the supports my special education co-teacher provides remain crucial. What’s more, I am still searching for ways to help students become more independent in processing this data, relying more on each other or a few guiding questions than me. But with an increased focus on the NGSS science practices at my school, it’s been exciting to find meaningful ways beyond lab reports to emphasize skills such as using models and interpreting data. I have also found that the open-ended nature of this task has made differentiation easier: all students can find simple groups of atoms, but there is enough richness in the data for students to seek out subtler patterns (such differences between “s” and “p” electrons) or to work backwards to predict ionization energy data from a model atom. And most importantly, I love how empowering it is for students to finally be able to say that they can explain why scientists represent electrons in different locations, and that they themselves figured it out, too.

¹“Electron Configurations.” POGIL Activities for High School Chemistry.  Trout, L. ed. Batavia, IL: Flinn Scientific, 2012. Available from Flinn.

Women’s History Month (March 1 - 31, 2017) honors the contributions of women to American culture and society. The American Chemical Society has selected some women scientists that contributed to important discoveries during times of rampant gender discrimination. Rachel Holloway Lloyd was the first woman to earn a PhD in chemistry. Ellen H. Swallow Richards is best known for her advances in sanitary engineering. Alice Hamilton was known as the "first lady of industrial medicine". Gerty Theresa Cori and her husband were the first to outline the process of sugar metabolism. These are just a handful of the stories available. You can find the full list to explore on the ACS website.

The American Chemical Society is offering a new service in hopes of making science more accessible to the public. Each week they issue a short collection of science articles, written in an interesting and engaging style, that you might use with your students to help them make connections between the curriculum and their own lives. The service is called Discoveries!, and it is free. At this point, the articles are not available on a website, but are emailed to ACS members. I am posting examples of the articles below with permission.

I am always on the lookout for science articles that I can share with my own students. I appreciate that these are written at a level any of my students can handle. Even better, if my students want to investigate further, they can access the original full text version.

Corralling stink bugs could lead to better wine

Journal of Agricultural and Food Chemistry

To wine makers, stink bugs are more than a nuisance. These tiny pests can hitch rides on grapes going through the wine making process, releasing stress compounds that can foul the smell and taste of the finished product. Now, in a study published in the Journal of Agricultural and Food Chemistry, scientists report the threshold of stink bugs per grape cluster that will impact the integrity of the wine.

In vineyards, brown marmorated stink bugs feed on grapes, reducing their yield and quality. And because they are small and blend in, the insects hitchhike on the grapes and wind up in the winery, giving off stress compounds that sometimes affecting the quality of the wine and juice. Pesticides used in the vineyard are not completely effective, so attention is being focused on ways to reduce the presence of the insects in wineries post-harvest. To find out exactly how grape processing impacts the release of stink bug stress compounds and how this affects wine, Elizabeth Tomasino and colleagues took a closer look.

The researchers placed varying numbers of live or dead stink bugs on grapes and measured the release of insect stress compounds as wine was produced from the fruits. The found that pressing was a key step in the release of two of the most common stress compounds — tridecane, which is odorless, and (E)-2-decenal, which produces an undesirable musty-like, coriander or cilantro aroma. Interestingly, white wine was contaminated less often than red. The researchers suggest that this is because these two wines are pressed at different points in the winemaking process. The team concludes that if winemakers could limit stink bugs to no more than three per grape cluster, the levels of tridecane and (E)-2-decenal in wine would be below the consumer rejection threshold.

The authors acknowledge funding from the National Institute of Food and Agriculture, U.S. Department of Agriculture and the U.S. Department of Agriculture, Northwest Center for Small Fruits Research.

Download Full Text Article.

Expanding point-of-care disease diagnostics with ultrasound (video)

ACS Nano

Fast, accurate and inexpensive medical tests in a doctor's office are only possible for some conditions. To create new in-office diagnostics for additional diseases, researchers report in the journal ACS Nano a new technique that uses ultrasound to concentrate fluorescently labeled disease biomarkers otherwise impossible to detect with current equipment in an office setting. The markers' signal could someday be analyzed via a smartphone app.

Ultrasound is a safe, noninvasive, inexpensive and portable technique best known for monitoring pregnancies. But these high-frequency acoustic waves can also be used to gently handle blood components, cells and protein crystals at the microscopic level. With an eye toward point-of-care diagnostic applications, Ton Huang, Zhangming Mao and colleagues wanted to harness these sound waves to help detect even smaller particles and biomarkers for diseases such as cancer that often require special laboratory equipment to detect.

The researchers developed an acoustofluidic chip that, though vibrations, can form a streaming vortex inside a tiny glass capillary tube using a minimal amount of energy. Testing showed that the vortex could force nanoparticles ranging in diameter from 80 to 500 nanometers to swirl into the center of the capillary. The nanoparticles captured biomarkers labeled with a fluorscent tag, concentrating  them in the capillary to boost their signal. This increased brightness could make the signal readable with a smartphone camera.

The authors acknowledge funding from the National Institutes of Health and the National Science Foundation.

Watch the Headline Science video here explaining the diagnostic technique.

Download Full Text Article.

Using E. coli to detect hormone disruptors in the environment

ACS Central Science

Endocrine disrupting chemicals (EDCs) have been implicated in the development of obesity, diabetes and cancer and are found in a wide array of products including pesticides, plastics and pharmaceuticals. EDCs are potentially harmful, even at low concentrations, equal in some cases to mere milligrams dissolved in in a swimming pool full of water. Now researchers report in ACS Central Science that they can quickly detect environmentally relevant concentrations of EDCs using engineered E. coli bacteria.

Detecting EDCs can be tough because the classification is based on their activity — disrupting hormone function — instead of their structures. Thus the term encompasses a broad spectrum of chemicals and often, health risks arise from aggregate exposure to several different species. Because many EDCs act on the same hormone receptors on a cell's surface, researchers have been developing tests that detect the compounds based on their ability to interfere with hormones. But these methods currently take days to produce a result or involve many complicated and expensive steps. Here, Matthew Francis and colleagues overcame these challenges by using E. coli in their device.

Non-toxic, dead E. coli cells display an estrogen receptor on the surface of the researchers' portable sensor. A protein on the sensor surface recognizes the EDC-E. coli complex, producing an electronic read-out in minutes. The inexpensive device can determine the concentration of many known EDCs individually and overall concentrations as mixtures. They tested the detection in water and in complex solutions like baby formula. It also can detect EDCs released into liquid from a plastic baby bottle following microwave heating. The team notes that their test is suitable for use in the field and can be modified to test for other types of chemicals that act on human receptors.

The authors acknowledge funding from the HoundLabs, the National Science Foundation and the Beckman Foundation.

Download Full Text Article.

Watching water freeze (video)

ACS Omega

Every winter, snow and ice dusts mountains and makes roads slick in cold climates. This phenomenon is ages old, but a detailed explanation for how ice crystals form has eluded us. In a study appearing in the journal ACS Omega, scientists now report a method to visualize ice in three dimensions as it grows. This knowledge could have a range of potential uses in materials science, geophysics, biology and food engineering.

What scientists know for sure is that ice shape and size depend on a number of factors, such as pH, the speed at which the temperature drops and the composition of additives. They have tried controlling ice shape by adding a variety of compounds, including sugar, ethanol and naturally occurring anti-freeze proteins from fishes, plants and insects. But to gain a deeper understanding of how ice forms — and potentially to have better control over the process — scientists have been working on new ways to watch crystals grow in real time. Several methods have been attempted, but none have provided reliable 3-D visualizations. A team of scientists from the Ceramics Synthesis and Functionalization Lab in France took a different approach.

The researchers demonstrated that confocal laser scanning microscopy and image analysis can rapidly capture a series of pictures showing the ice crystals growing. The images can then be used to measure how fast the crystals expand and lengthen. The approach has promise for further studying ice growth under varying conditions and with the addition of polymers, proteins or other compounds, the researchers say.

The authors acknowledge funding from the European Research Council.

Watch ice crystals form in this video.

Download Full Text Article.

How do you support growth in your students’ writing and communication over time? There are so many things: Claim, Evidence, Reasoning (CER) scaffolds, sentence starters, and more. How might all of these tools used in introductory courses come together in an upper-level course? In this post, I will focus upon my AP Chemistry lab notebook set-up.

Inspiration:

• http://chemistry.oregonstate.edu/writing/WritingGuide2000.htm
• http://avogadro.chem.iastate.edu/SWH/Lab_report.htm
• Tom Nichols, Denver South High School (via Dr. Carey Johnson, University of Kansas)

I require my students to purchase a composition notebook and a folder. I try to keep the cost down (e.g., no carbon copy notebook), as they also have to purchase their own textbooks, review books, exam fees, and class t-shirt. Why the folder? They keep their rubrics and any lab packets that accompany their work in one handy place.

Here is what I give my AP students on day 1 of class. They tape this in the inside of their composition notebook and set up their notebook (most students bring their supplies day 1- I have a few extra composition notebooks lying around for any stragglers).

Pros:

• Everything is in one place for both me and students.
• Reduces anxiety on lab reports for some students - they know they are in for a lot of work in AP chemistry, and for some reason, hand-writing reports for some reduces the “scary” barrier. (This might also have something to do with the super long reports they were required to write for me in first year chemistry, but I digress.)
• Leaving the left-hand side of each page for scratchwork is a genius idea - I wish I could take credit. Some students used it all the time, some never used it. However, it allows me to see more of the progression in thinking, instead of the cleaned-up final product. Note: I did allow students to draw arrows to what they wanted me to grade on the left side so they did not have to rewrite everything.

Cons:

• If I want to document student work, I had to take pictures or re-type their work.
• In our increasingly digital world, I have gotten used to packing light. Those folders and notebooks are huge and are a pain to move around (e.g., take home to grade). (This is a personal problem and feel free to laugh at my laziness.)
• This method can be tricky for some POGIL-like labs, and I have had to learn to be very clear to students how this translates into their notebook. My students have told me that without posting the individual lab rubrics, a lab packet with embedded questions in addition to the final notebook write-up can be a bit confusing.

Day 2 of AP Chemistry is their first lab - decomposition of NaHCO₃ as a stoichiometry review (basically the Flinn lab with a few edits, posted below along with the rubric) and practice using their lab notebooks right away.

What have you found that works or doesn’t work (just as valuable to share) in your context? Please share below!

"What are we doing to help kids achieve?"

     Formative assessment can be a double edged sword. It can be and often is extremely helpful. Some quick short three or four well worded questions at the beginning of a unit provides information about student abilities. A teacher can skip teaching information that kids already know or the teacher can discover concepts that he or she assumed students know but do not. Formative assessment about "Moles" can provide data that is hard to deal with. Can the students handle scientific notation? How well are students at basic math skills? Are students able to use dimensional analysis? Can students reason proportionaly? Here is the really hard part...what do you do if for every question asked you get a class that is all over the map? At what point do you tell a student that he or she has some basic math skills that need to be addressed and this is chemistry class?

     The struggle can be overwhelming. It is too easy to get caught up with "paralysis by analysis". Everything can be so overwhelming that one gets stuck doing nothing or following the path of least resistance.  So, if mistakes are going to be made, why not at least try to stick with what research says works and hope for the best?

     First, research says to start with a hands on activity. We attempted to do a "beans" lab. Students found relative masses of beans and found that if they had a "pot" of beans based on relative masses of beans it was always about the same number of beans. They attempted to do simple calculations. Then we tried to compare the "pot" to "moles".

     It was a struggle. A student said that if there was a mole of marbles that it would cover the Earth nine miles high in marbles. He was being completely honest when he said he just could not conceive of such a large number and thought that it was incredible that we had a jar of sulfur that was a mole of sulfur. It is honestly difficult to reason with concepts that are so large that they are hard to imagine.

     Second, I understand that this might be a statement some have strong feelings about, but if a student shows the work, labels the numbers and explains how he or she got the answer, does it really matter what method is used? Is there really only one right way that should be accepted? Why not show several methods to the students, provide the pros and cons of each and let them use the one that works for them?

     Here is another practice that I am not sure about and am having second thoughts....is it O.K. to say, "We are going to do some worksheets with these problems (after experiments and demonstrations). Pretend I am stupid and show me how to solve the problems."

     Regardless...I have students with a wide variety of mathematical and reasoning skills. So the question is, where do I go from here now that we are headed into stoichiometry? Well, I have a possible place to start. I am going to tell students that we are going to cook smores. The "balanced" equation for a smore is two pieces of chocolate, one marshmallow and two small graham crackers yields one smore. I challenge my students to tell me exactly how much money I need to spend on supplies so each student gets one smore. If they do, then we will cook smores. Teenagers find that food and bunsen burners are powerful motivators.

    Last but not least...students still need to balance equations and do stoichiometry. Stephanie Kimberlin of Project TIMU developed a wonderful activity called "Balancing the Particulate Way" specifically designed to help students develop stoichiometry skills when they struggle with math. In other words....gotta keep on trying...the students are worth it.

     Do you have a mole or stoichiometry activity that works well with students?  Please comment or post it...we would love to hear from you.

HCl and NaOH, a strong acid - strong base titration? Citric acid and NaOH, a weak, triprotic acid - strong base titration? Do your students standardize the NaOH solution as a first step?

As a second year AP teacher, I am full of questions about acid-base chemistry pedagogy. College Board's AP Insight program lays out guided inquiry activities to address this core "challenge area." The activities build students' conceptual understandings of the following topics:

• Strong acids
• Bronsted-Lowry theory
• Weak acid and weak base net ionic equations
• Significance of strong conjugate acids and strong conjugate bases producing additional H⁺ and OH^-
• pH and pOH calculations
• Dissociation equations and ICE charts for weak acids and bases
• Neutralization equations and ICL charts for strong acids and bases
• Titrations curves (equivalence points, half-equivalence points, buffering regions)
• Bond strengths and understanding acid-base strength
• How buffers work
• Setting up a buffer

These performance tasks have helped me tremendously this year, and I am feeling more confident about my students' conceptual knowledge.

However, the AP exam seems to regularly ask a free response question about titration. Like everyone else, we are pushed for time. Some veteran AP teachers suggest using a virtual lab, some suggest doing a demonstration, others suggest a full standardization of NaOH with a strong acid titration, and still others have encouraged a weak acid titration as they believe buffer systems are only understood when experienced. Can my students be successful if we don't titrate a weak acid? Can my students adequately answer the free response question if I wait to titrate in lab until after the exam? What is your opinion? I can't be the only new AP teacher wondering, right? 

     If this is a site all about chemistry teaching, what in the world does a book called "10% Happier" have to do with anything? Let me explain....I'll try the short, condensed, one page executive summary.

     Dan Harris is a T.V. anchor who is in front of millions of people every day. You can imagine the problem he faced when he had a panic attack live, on air and in front of about 5 million people. A doctor checked him out and concluded that it was not physical problems, but mental. Meditation was recommended. Dan thought it was crazy but decided to investigate it because that is what he does. This is his story. It is funny, scary and a good read. So what does this have to do with chemistry?

     Dan went on a weird journey and discovered meditation. This is the same meditation, or "mindfullness", that is practiced by top executives across the world, prescribed by doctors for stress reduction and has been studied since the mid-seventies and has been found to have substancial benefits. The Marines now have a program to have their soldiers meditate....no kidding. This book also has an app and a podcast that goes with it. Before I get into the chemistry part...here is what meditation or "mindfulness" won't do for you.

     It won't provide a miracle cure over night. It won't make you better looking, help you lose 100 pounds in three weeks or turn you into a zombie. You won't have to wear a robe, burn incense or sit for hours on end. Here is what it might do for you. For about fifteen minutes a day, you will "hack" your brain. It allows you to be aware of what is happening inside your head. Then, when you are not meditating, you can have moments throughout the day in which when everything is coming at you at a hundred miles an hour, you can put your brain on pause for half a second, be mindfull of the good, bad and ugly and choose the most usefull. You can learn to respond instead of react. It is does not work all of the time, but most of the time if you work at it. I don't know about you but even if I can respond better some of the time it is worth it. So here is what happened to me....

     I started using the app for free. Each fifteen minute session starts with a two to three minute video in which Dan asks a meditation expert questions that anyone would ask who knows nothing about meditation. Then the expert usually replies in a simple no nononsense way. The expert then leads you on a ten to twelve minute meditation. The first time I tried this, my mind started to wander during the first three seconds of meditating. Strange as it sounds, this is normal and it means that it is working. The fact that I could tell my mind was wandering means that I am aware of my thinking and this is the point. Next, the plan is not to block out anything, but to take everything in, make a mental note of it in a non judgemental way and then move on. So if you have an itch, it is not that it is good or bad or that you should scratch it or avoid it. The plan is to be aware of it, make a note of it and then usually it will pass and you move on. It takes some practice but it works. Now...how does this apply for when someone is not meditating?

     I was talking to a fellow teacher about an idea I had. This person suddenly and unexpectedly became negative and hostile toward the idea. I could feel my blood pressure rising and started getting defensive. Suddenly, and just for a second, I was able to recognize the behavior, identify it, label it and move on. It gave me a split second to decide what is useful and what is not. It helped me to make the choice to respond and not react. Later I decided that my decision should be based on what research says is best for students and not my emotional state.

     If you are an inolved teacher of chemistry, chances are your classroom, and thus a significant part of your professional life, is "messy". You have kids orally defend their position instead of just doing a worksheet. You may want them to develop their own models instead of giving them the answer. You challenge them instead of just giving them a grade. On top of that there are the kids on 504's, IEP's, phone calls, formative assessments and lab set ups and break downs and you try to take it seriously. And while you are working with one group to have them explain the data, another is texting and trying to find the answer key on their phone. You want to do the demonstration instead of just decribing it the experiment.  Sometimes it goes well...but sometimes it does not. You might get challenged because you don't just "give them the answer". Then students are coming in to make up tests, labs and grades after school but there is also a faculty meeting. Most days it is mentally exhausting and if not carefull over time the stress in dealing with all of this can seem like a "corrosive drip". You may not notice it at first, but over time the "corrosive drip" of the stress can turn a person into someone that behaves in a way that is not always positive or in the best interest of the students. This book is meditation for the masses and can be one of many tools that is a small life preserver for the involved chemistry teacher. It helps the teacher mentally and in a non judgemental way simply be aware of all that is and then decide what is useful....again, it helps one to respond instead of react.  It helps to prevent the corrosive drip of the stress of being bombarded with questions and commitments. This lowers the stress and eventually helps us stay focused on why we started teaching in the first place, because of the students and the love of science.

     Sound like someone you know? Sound like this is worth fifteen minutes a day? What if a normal person could walk you through a method that would allow you to push a mental "pause" button, be aware of what is around you, and then allow you to choose that which is most useful? If interested...take a look at "10% Happier". It is well worth the time and investment.

Promoting Problem-Solving and Discovery Learning

The March 2017 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: protein chemistry; making connections in in chemical education research; chemical bonding; importance of non-technical skills; courses built on reactivity; periodic table; heterocyclic compounds; teaching resources; from the archives: Using Wikipedia and Wikis to teach.

Cover: Protein Chemistry

Students often have difficulties understanding that proteins routinely exist in both folded and unfolded states, and that protein unfolding is not equivalent to irreversible denaturation or aggregation. In Naked-Eye Detection of Reversible Protein Folding and Unfolding in Aqueous Solution, Tess M. Carlson, Kevin W. Lam, Carol W. Lam, Jimmy Z. He, James H. Maynard, and Silvia Cavagnero describe a novel, simple, and visually engaging illustration of the reversible interconversion between folded and unfolded protein states and of the dramatic effect of pH, temperature, and stabilizing/destabilizing cosolutes on protein conformation.

Protein chemistry is also explored in these articles:

Proteins and Drug Design

Drug Design Workshop: A Web-Based Educational Tool To Introduce Computer-Aided Drug Design to the General Public ~ Antoine Daina, Marie-Claude Blatter, Vivienne Baillie Gerritsen, Patricia M. Palagi, Diana Marek, Ioannis Xenarios, Torsten Schwede, Olivier Michielin, and Vincent Zoete

Demonstration of AutoDock as an Educational Tool for Drug Discovery ~ Travis R. Helgren and Timothy J. Hagen

Using an in Silico Approach To Teach 3D Pharmacodynamics of the Drug–Target Interaction Process Focusing on Selective COX2 Inhibition by Celecoxib ~ Maurício T. Tavares, Marina C. Primi, Nuno A. T. F. Silva, Camila F. Carvalho, Micael R. Cunha, and Roberto Parise-Filho

Protein Experiments

Development and Implementation of a Protein–Protein Binding Experiment To Teach Intermolecular Interactions in High School or Undergraduate Classrooms ~ Sadie M. Johnson, Cassidy Javner, and Benjamin J. Hackel

Utilizing Mechanistic Cross-Linking Technology To Study Protein–Protein Interactions: An Experiment Designed for an Undergraduate Biochemistry Lab ~ Kara Finzel, Joris Beld, Michael D. Burkart, and Louise K. Charkoudian

Unboiling an Egg: An Introduction to Circular Dichroism and Protein Refolding ~ John P. Hoben, Jianing Wang, and Anne-Frances Miller

Capillary Zone Electrophoresis for the Analysis of Peptides: Fostering Students’ Problem-Solving and Discovery Learning in an Undergraduate Laboratory Experiment ~ Jessica C. Albright and Douglas J. Beussman

Op-Ed

Editor-in-Chief Norbert J. Pienta asks How Do We Measure Success in Introductory College Chemistry?

Jonathan S. Rhoad suggests using a pair of writing assignments that challenge students to gain a deeper understanding of underlying concepts and to read their textbook critically in the Commentary Written Assignments in Organic Chemistry: Critical Reading and Creative Writing.

Making Connections in Chemical Education Research

Development of the Connected Chemistry as Formative Assessment Pedagogy for High School Chemistry Teaching ~ Mihwa Park, Xiufeng Liu, Noemi Waight

Unraveling the Complexities: An Investigation of the Factors That Induce Load in Chemistry Students Constructing Lewis Structures ~ Jessica M. Tiettmeyer, Amelia F. Coleman, Ryan S. Balok, Tyler W. Gampp, Patrick L. Duffy, Kristina M. Mazzarone, and Nathaniel P. Grove

Chemical Bonding

In Emphasizing the Significance of Electrostatic Interactions in Chemical Bonding, Bhawani Venkataraman describes a pedagogical approach to help students understand chemical bonding by emphasizing the importance of electrostatic interactions between atoms. A previously published article by Bhawani Venkataraman with Elinor Gottschalk, Visualizing Dispersion Interactions,uses an animation and accompanying activity to help students visualize how dispersion interactions arise.

Courses Built on Reactivity

In Reactivity III: An Advanced Course in Integrated Organic, Inorganic, and Biochemistry , Chris P. Schaller, Kate J. Graham, and Henry V. Jakubowski describe a new course that presents chemical reactions from the domains of organic, inorganic, and biochemistry that are not readily categorized by electrophile–nucleophile interactions. This is built on two previously published articles:

Reactivity I: A Foundation-Level Course for Both Majors and Nonmajors in Integrated Organic, Inorganic, and Biochemistry ~ Chris P. Schaller, Kate J. Graham, Brian J. Johnson, T. Nicholas Jones, and Edward J. McIntee

Reactivity II: A Second Foundation-Level Course in Integrated Organic, Inorganic, and Biochemistry ~ Chris P. Schaller, Kate J. Graham, Edward J. McIntee, T. Nicholas Jones, and Brian J. Johnson

Importance of Non-technical Skills

Anne E. Kondo and Justin D. Fair reveal in Insight into the Chemistry Skills Gap: The Duality between Expected and Desired Skills that companies value effective teamwork and communication skills. These non-technical skills can be achieved when a strong foundation of interprofessional skills has been taught and applied in scientific settings, such as through undergraduate research.

Periodic Table

Clarifying Atomic Weights: A 2016 Four-Figure Table of Standard and Conventional Atomic Weights ~ Tyler B. Coplen, Fabienne Meyers, and Norman E. Holden

Technetium: The First Radioelement on the Periodic Table ~ Erik V. Johnstone, Mary Anne Yates, Frederic Poineau, Alfred P. Sattelberger, and Kenneth R. Czerwinski

Heterocyclic Compounds

Synthesis and Characterization of 2-Phenylimidazo[1,2-a]pyridine: A Privileged Structure for Medicinal Chemistry by Brandi S. Santaniello, Matthew J. Price, and James K. Murray, Jr. describes a straightforward hetrocyclic synthesis. The authors point out that heterocyclic compounds, in particular N-heterocycles, are pervasive in compounds of medicinal and biological interest, as revealed in:

A Graphical Journey of Innovative Organic Architectures That Have Improved Our Lives ~Nicholas A. McGrath, Matthew Brichacek, and Jon T. Njardarson

An In-Pharm-ative Educational Poster Anthology Highlighting the Therapeutic Agents That Chronicle Our Medicinal History ~ Elizabeth A. Ilardi, Edon Vitaku, and Jon T. Njardarson

Teaching Resources

Understanding Chemical Equilibrium: The Role of Gas Phases and Mixing Contributions in the Minimum of Free Energy Plots ~ J. Pablo Tomba

Interactive Simulations To Support Quantum Mechanics Instruction for Chemistry Students ~ Antje Kohnle, Cory Benfield, Georg Hähner, and Mark Paetkau

Calculating the Confidence and Prediction Limits of a Rate Constant at a Given Temperature from an Arrhenius Equation Using Excel ~ Ronald A. Hites

From the Archives: Using Wikipedia and Wikis To Teach

Michael D. Mandler dicusses Glaring Chemical Errors Persist for Years on Wikipedia and encourages timely fact-checking and editing by the chemical community in order to make Wikipedia a more useful resource. Other articles that have discussed using Wikipedia and Wikis to teach include:

Using Wikipedia To Develop Students’ Critical Analysis Skills in the Undergraduate Chemistry Curriculum ~ Eric Martineau and Louise Boisvert

Improving Information Literacy Skills through Learning To Use and Edit Wikipedia: A Chemistry Perspective ~ Martin A. Walker and Ye Li

Using Wikis To Develop Collaborative Communities in an Environmental Chemistry Course ~Laura E. Pence and Harry E. Pence

Using Chem-Wiki To Increase Student Collaboration through Online Lab Reporting ~Edward W. Elliott, III and Ana Fraiman

Improving Science Education and Understanding through Editing Wikipedia ~ Cheryl L. Moy, Jonas R. Locke, Brian P. Coppola, and Anne J. McNeil

A Wiki-Based Group Project in an Inorganic Chemistry Foundation Course ~Kathleen E. Kristian

A Collaborative, Wiki-Based Organic Chemistry Project Incorporating Free Chemistry Software on the Web ~Michael J. Evans and Jeffrey S. Moore

Promoting Everything 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.

Do you have something to share? 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 recently updated: Author Guidelines, Document Templates, and Reference Guidelines.

Throw the phrase “chemistry class” at someone to get their reaction. What do you predict it would be? A chalkboard full of stoichiometry problems? Wading through the atomic masses on the periodic table? Bubbling beakers? Something else? In any case, I’m guessing his or her first answer would not be, “Creative writing.”

The March 2017 issue of the Journal of Chemical Education matches up these two phrases in the article Written Assignments in Organic Chemistry: Critical Reading and Creative Writing (freely available to all). The author’s specific application is within a university organic chemistry class, but the article could apply to the high school chemistry classroom as well. Rhoad includes two types of what he terms Journaling Assignments in his course, with a goal of increasing students’ depth of conceptual understanding of the material, as well as “develop[ing] in students better critical reading skills that should be applicable in whatever field they choose.”

Of the two types he uses, the one where creative writing comes into play is “SEE–I,” or statement, elaboration, example, illustration. The instructor gives a certain chemistry concept, then students journal each of the four pieces. Creative writing is needed in the fourth step, since the illustration should not use chemical terms, but rather paint a picture that helps one to understand the concept. One example from the online supporting information is an illustration for tautometers, which likens them to two fishing boats, describing the relation of their slightly different arrangements to each other. The topics selected could be easily adjusted to fit one’s specific chemistry curriculum. It is the most difficult step, Rhoads admits, but can also give “the most indication of student understanding of the topic.” The exercise reminded me of part of my son's middle school writing curriculum, Classical Composition. One step of each essay is to develop an analogy that compares an action to a dissimilar action that has the same effect, such as a comparison of preparing for war with developing soccer skills. It is a step that takes some serious thought, but appears to deepen his consideration of the writing topic. I like the idea of integrating this type of writing into chemistry, even in a limited way, as one slightly different way of touching on a concept. 

Writing, this time for educators and others in the chemistry community, is also the focus of a letter from this month’s issue, Glaring Chemical Errors Persist for Years on Wikipedia (freely available to all). Mandler speaks to a past article (available to JCE subscribers) about teaching students to critically read a Wikipedia article and to correct it if they find errors. A more recent article, mentioned in the March 2016 Especially JCE post, has a similar suggestion. Mandler brings up specific instances of structural errors (albeit in portions high school students are unlikely to reference at a general chemistry level) that have lingered on Wikipedia even after they are reported. He encourages those in the chemistry community (industry, government, academia) to become Wikipedia editors, so that the resulting pages there reflect what is seen in peer-reviewed literature. Work from the chemistry community is needed so that accurate information can be passed along to readers such as students and the general public who use Wikipedia.

More from the March 2017 Issue

Don’t miss Mary Saecker’s JCE 94.03 March 2017 Issue Highlights for further content from this month’s issue of the Journal. She includes a great “Using Wikipedia and Wikis To Teach” list with multiple articles from the JCE archives.

Have something to say about a current or past article from JCE? We want to hear! Start by submitting a contribution form, explaining you would 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.

In 2006, The Division of Chemical Education endowed an award program, the Regional Award for Excellence in High School Teaching, to recognize and inspire outstanding high school chemistry teachers. Each of the ten Regions of the American Chemical Society solicits nominations for this award. The winners receive $1000, an engraved plaque and travel expenses to the meeting where they are honored.

I am writing this post to encourage nominations for these awards. I dare say that there are hundreds of worthy candidates in each region, but the nominations are lacking. If you know an outstanding teacher of chemistry, please nominate them for this prestigious award. Also, I hope you will share this information with your chemistry education network. Awardees do not need to be members of ACS.

You can find more information about the specifics of the Region Awards on the ACS Division of Chemical Education website.

To help facilitate this effort, I have drafted three documents: Being an Effective Nominator, Do I Need a Curriculum Vitae? and Writing a Teaching Philosophy Statement.  You can find the links under Supporting Information below the post. I hope that you and the teacher you nominate will find them useful.

You can view a table of past award Region Award winners on the American Chemical Society website along with more information related to the award.

I was at a workshop recently, when a friend suggested I read, Chemistry: A Very Short Introduction by Peter Atkins, Oxford University Press. The friend suggested the book would not take long to read, and given the name included the phrase "A very short introduction" who was I to argue? So I bought the Kindle Version of the book for about $7 U.S. and got to reading.

The book, published in 2015, has only seven chapters, each with compelling connections to the world around us. The chapters are as follows:

Its origins, scope, and organization

Its principles: atoms and molecules

Its principles: energy and entropy

Its reactions

Its techniques

Its achievements

Its future

In the first chapter on origins, scope, and organization, Atkins gives us some brief background on significant figures in chemistry such as John Dalton. But the focus is on the progression of ideas within chemistry, not the people involved. He concludes this section with a look at what we would probably call branches of chemistry, such as organic, physical, and analytical chemistry.

In chapter two, Atkins delves into the atomic and molecular world, starting with the development of the periodic table and Mendeleev's contributions. The following quote really resonates with me:

"The Periodic Table portrays an extraordinary feature of matter: that the elements are related to one another. We are now so familiar with the table that that feature is easily forgotten. But imagine yourself in an era before the table had been formulated. Then would you have known of the gas oxygen and the yellow solid sulfur, and would almost certainly not have dreamt that there could be any relationship between them."

The chapter continues with a discussion of bonding and the importance of electrons in this endeavor. He touches on ionic, covalent and metallic bonding, and the relationship between the electrons in the bonding and the properties that result from this.

Chapter 3 was quite relevant to me at the time I was reading it, as my year 1 IB Chemistry students were learning about energetics (Topic 5 and 15 for those of you that teach IB). He delves briefly into the First and Second Law of Thermodynamics. He touches on enthalpy and entropy, and gives a brief hint about Gibb's Free Energy, although not by name. I appreciated the idea that entropy is a "signpost of change" as he called it. This chapter continues with a discussion of rates of reaction and equilibrium. I quite like how it ties all of these ideas together. At the conclusion of many of the chapters there was a small section, usually titled something approximately like, "Where we are, and where we are going." It was a nice bit of closure on the current chapter and a short preview of things to come.  And with that, he leads us to the next step, the atomic rearrangement of reactants that leads to products.

As suggested, Chapter 4 deals with reactions. I found it instructive in many ways, as he distills the veritable plethora of reactions into four major types:

Proton transfer: acids and bases

Electron transfer: oxidation and reduction

Radical reactions

Lewis Acid-Base Reactions

I will be the first to admit here that I have not yet begun to integrate this into my teaching - but I'm planning to do so on Tuesday with my Year 1 students. And my Year 2 IB students will be getting a taste of this summary after mock exams as a way to help tie things together during their review.

One of my favorite chapters came next, with a look at the techniques of chemistry. I have always had a bias toward analytical chemistry. In truth, it may have come from early visits to my dad's laboratory, when he worked at a local hospital running blood and urine assays before the days of automation. Then later, in college when I was choosing chemistry as a major he had moved to a state Department of Ecology lab as a water quality chemist. He always talked about his love for "being on the bench" as a chemist, and he passed that love to me. So Chapter 5 was a trip down memory lane - and I loved every minute of it. After a brief introduction, Atkins delves into NMR, Mass Spec, X-Ray diffraction, and picturing surfaces using atomic force microscopy and scanning tunneling microscopy. He concludes the discussion with a look at modern synthetic chemistry - especially in drug discovery.

Throughout each chapter, Atkins relates chemistry to history, and brings us on a journey of discovery from our early understandings of the atomic world. But in Chapter 6 he focuses on the achievements of chemists. The list of achievements discussed is quite lengthy, but of course given the "short introduction" we are receiving by Atkins it only touches the surface. But he doesn't shy away from controversy either. For example, Fritz Haber gets a mention for his contribution to agriculture, and some scorn for being, "…a leader in the development of poison gas." He also discusses many environmental issues caused by the use - and misuse - of chemicals.

And the final chapter about the future of chemistry gave just a glimpse of the possibilities in front of us related to chemistry. Of course nanotechnology gets many lines of print, but looks at other areas of growth such as catalysis and molecular biology.

His last paragraph sums things up quite well:

Such is the joy, the intellectual pleasure, that modern chemistry inspires. I hope these pages have erased to some extent those memories that might have contaminated your vision of this extraordinary subject and that you have shared a little of that pleasure.

Yes, Dr. Atkins, I have indeed!

Overall, there are very few chemical formulas, and as you would expect there isn't a lot of depth to the discussion. But that's not the point here. Rather, I felt this gave a very good "big picture overview" of the world of chemistry. And while this book is really intended for non-chemists to get a peak into our world, I found it enlightening in many ways.

I plan on finding ways to share this with my class. I have even put in a budget request to get a class set so we can do some reading together and look at the ideas in their simplest forms in order to get that "big picture overview" that I just mentioned. I don't see this book as a way to learn new ideas, but rather to consolidate what we know and enhance the connections between the topics that our students often struggle to make.

Beyond all that, I'm just as intrigued with the suggested "Further Reading" at the conclusion of the book. Atkins offers a few suggestions from his own collection of 70+ books, but there are a few other suggestions that I will be adding to my "To Read" list. Next: Four Laws that Drive the Universe, also by Peter Atkins.

What are you reading right now that is chemistry-related? Any suggestions for my book collection?

As our Gas Laws unit was coming to an end, it was time to create the test. As I thought of potential test questions that were both challenging and in alignment with the learning objectives we had previously identified for the unit, I was reminded of a multiple-choice question I had been shown in an old Modeling Instruction^TM resource.

Which of the following samples of gas will have the greatest pressure if they all have the same volume?

  A. 10 moles at 80 ⁰C        B. 10 moles at 70 ⁰C        C. 5 moles at 81 ⁰C       D. 2 moles at 82 ⁰C

I loved this question because it required a particle-level understanding of pressure. Since we continuously try to connect the macro level with the particulate level, it served as a useful conceptual question. More specifically, there is no memorized equation/formula that could potentially mask understanding and no mnemonic device to rely on. Instead, it just requires a moment in which you must stop and think about how the two variables, moles and temperature, relate to pressure. In other words, the only thing students need to do is ask themselves, “which of these answers would produce the most amount of collisions¹ with the inner walls of the container?”

To be honest, I was pretty confident in my students’ ability to answer this question correctly. After all, the idea of pressure came up frequently throughout the unit which meant we had multiple opportunities to explain why pressure would increase or decrease from a particle-level perspective. Within these opportunities, feedback was provided with the hope that it would be used to improve future explanations and overall understanding. In fact, I saw the majority of students citing the concept of particle-wall collisions much more frequently after they were given time to acknowledge previous feedback.

However, as I was grading the tests, I started to notice something—many students were choosing answers that I had previously thought would have been easily dismissed. After I was done grading the tests, I decided to look at the data.

Which of the following samples of gas will have the greatest pressure if they all have the same volume?

  A. 10 moles at 80 ⁰C        B. 10 moles at 70 ⁰C        C. 5 moles at 81 ⁰C       D. 2 moles at 82 ⁰C

Out of 160 students:

16% (26) chose B—10 moles at 70 ⁰C

17% (27) chose D—2 moles at 82 ⁰C

How was it possible that 1/3 of my students got this question wrong?! After reflecting on this for a bit, here is what I think happened and how it reflects a recurring issue especially in science education.

Answer—10 moles at 70 ⁰C

Of all the answers available, I thought this one was going to be the easiest to dismiss. After all, if answers A and B both had the same number of moles but one was at a lower temperature, how could the answer with a lower temperature possibly cause a greater frequency of collisions? It wasn’t until I started to look at some of the tests that I noticed some of the “work” students were doing on the side. Students were literally plugging in temperature values from answers A and B to a memorized equation (Gay-Lussac’s Law or the Combined Gas Law) which lead through a line of reasoning that appeared to go something like this:

screen_shot_2017-03-20_at_3.51.07_pm.png

The bigger the bottom number (temp) the smaller the answer will be. Therefore, the smaller of these two temperatures will result in the greater pressure.

Forget the fact that it’s a complete misuse of Gay-Lussac’s Law or the Combined Gas Law. Forget the fact that the mathematical reasoning they were trying to use doesn’t even make sense. My biggest concern here was that the moment they saw some numbers, they instantly resorted to an equation, which was completely misused.

In case you’re wondering, nobody tried using the Ideal Gas Law.

To be clear, it’s not that I’m necessarily against using an equation to prove an answer to a conceptual question that could have easily been solved for after a moment of thinking about it. What is most interesting to me is the number of students that were SO RELIANT and SO CONFIDENT in their memorized formulas, that using them completely blocked out the thought process that would have allowed them to see the obvious contradiction in their answer.

So, what about the students that chose the other answer?

Answer—2 moles at 82 ⁰C 

I think the thought process that would lead someone to choose this answer is much easier to explain. Students knew about the directly proportional relationship between pressure and temperature. They reasoned that the higher the temperature, the more collisions. Therefore, they chose the answer with the highest temperature.

Though these students showed no evidence of plugging values into memorized formulas, I consider their error in reasoning to fall within the same category as the other group. Instead of resorting to a memorized formula, they instantly resorted to a memorized procedural relationship: As temperature increases, pressure increases. In doing so, it completely blocked out any consideration of the effect that the number of moles present in each sample would have or even the small discrepancy between temperature values among the answers available. Not only that, like the students from the other group, they misused the concept of Gay-Lussac’s Law by forgetting the fact that it’s only true when both volume and moles are held constant.

The two groups of students that I identified are made up of students with reasoning skills all over the spectrum and earned grades on this test anywhere from an A to a D. To make it even weirder, this specific test had the highest performance of any test we have had throughout the year with an average of 82.5%.

So Why Am I Even Bringing This Up?

Regardless of the topic being taught, we can all think of situations or concepts that students typically resort to a more procedural way of thinking. Though the reason so many students approach many chemistry concepts this way is a topic that has been extensively researched,^2-4 I still find myself continuously “battling” with students to overcome the attraction to constantly approaching problems with an algorithmic or procedural mindset. Not only does this happen with students, but with colleagues as well—though it’s a bit more refined conversation.

Just to clarify, I did use a question from a Modeling Instruction^TM resource as the basis of this post. I have been trained in Modeling Instruction^TM but I am unable to use a full-blown version of the provided curriculum in my current teaching assignment. I do try to use many of the practices of Modeling Instruction^TM  but I neglected to use the PVnT tables that Modelers often use in the gas law unit. After seeing the above results, I am anxious to incorporate the PVnT tables into my gas law unit next year and compare the results for this question to what I saw this year. 

What are some strategies you use to not only promote a conceptual understanding but also teach students when algorithms are beneficial and when it’s potentially inappropriate to use them? How do you convince your students and colleagues that just because students may arrive at the correct answer, that doesn’t mean they understand what’s going on. In other words, why is it so difficult to convince people that quantitative correctness doesn’t automatically suggest understanding? If you have any thoughts or recommendations on the matter, I would love to hear them. Though this was just one example, it’s one of many that occur throughout the year and I want to do anything I can to promote thinking skills and overall reasoning ability.

¹Since pressure is not universally defined this way, I just wanted to provide a bit of clarity here. In Modeling Instruction^TM, the concept of pressure is explained using a model that primarily focuses on the frequency of collisions between particles and inner walls of the container. The more collisions, the more pressure and vice versa. For example, we can account for the increase in pressure when the temperature of a system is raised since the particles have a higher average kinetic energy which leads to an increase in the frequency of collisions between the particles and the inner walls of the container that hold them. You can learn more about Modeling Instruction^TM at http://modelinginstruction.org (accessed 3/20/17).

² Cracolice, Mark, John Deming, and Brian Ehlert. “Concept Learning versus Problem Solving: A Cognitive Difference.” Journal of Chemical Education 85-6 (2008):873-878

³ Gallet, Christian. “Problem-Solving Teaching in the Chemistry Laboratory: Leaving the Cooks…” Journal of Chemical Education 75-1 (1998): 72-77

⁴ de Vos, Wobbe, Berry van Berkel, and Adri Verdonk. “A Coherent Conceptual Structure of the Chemistry Curriculum.” Journal of Chemical Education 71-9 (1994): 743-746