chemical education

The Blogversation Continues: A New Approach to the Fear of Chemicals and for a Course of Action

This post is part of an on-going dialogue between chemists on Twitter in an effort to unite the chemistry community do something about negative portrayal of chemicals in a positive and productive manner. I responded to Renee Webster’s kick off post and we’ve gotten a lot of excellent feedback both on Twitter and from bloggers. I’d like to respond to all these amazing ideas by way of a response to bloggers Dr. Dorea Reeser (Chemicals Are You Friends) and Dr. Luke Gamon (A Radical Approach) who have upped the ante with their contributions to the blogversation. These posts are a wake-up call to the chemistry community by way of a completely new take on the situation.

Before I read these responses I wanted to figure out what to call the fear of chemicals in such a way that it didn’t lend itself to ridiculing people’s legitimate fear. I’ve argued that (#)chemophobia not only falls short of this but it perpetuates a negative image of chemicals. There was also the matter that (#)chemophobia inaccurately describes the way that the media and advertising capitalizes on this fear. I joined other chemists on Twitter in their search for alternatives but felt odd with our second attempt: (#)chemsploitation. Why is a term/hash-tag so important? I am of the opinion that it provides a way of checking that we do not damage our credibility with the way we represent ourselves. These responses elegantly change the focus on the debate on whether or not we need to get rid of (#)chemophobia.

Dr. Reeser explains that she avoids using the term chemophobia because it sends out the wrong message and because to those outside the debate and non-chemists, the term suggests something having to do with chemotherapy. She proposes the term/hash-tag (#)ChemMisConcept both to describe those that fear chemicals and those that perpetuate that fear. It meets all the criteria that I discussed in my previous response and has the added bonus of working in all contexts. The concept of chemical misconception(s) is as specific as it gets and this changes the way we approach the real problem: the fear of chemicals. This fear of chemicals is very real and rational considering that people have these misconceptions given the information they can access. Dr. Reeser reminds us that we have to acknowledge that chemical(s) include: dangerous substances which we should have a healthy fear of; substances where the danger depends on the dosage and those substances that are completely harmless. I agree that it is our job as chemists to explain which is which.


Dr. Gamon* agrees with Dr. Reese when he states that the energy that’s going into debating the word could be put to better use. He calls all chemists to take action with a cool head and in a respectful way and I couldn’t agree more. (#)Chemophobia just doesn’t serve this purpose and the term has outlived its use. Dr. Gamon reminds us that we are all brand ambassador, and I agree that we need to act like if we are going to take back the word chemical.


Dr. Gamon’s response agrees with a post Dr. Reeser directly cites, and I would be remiss for not addressing Chemophobia-phobia by Dr. Chad Jones* (@TheCollapsedPsi). Dr.Jones also suggest that we should hold ourselves, government agencies and other chemist/companies to higher standards. Education/information, policies and enforcement should be directly informed by evidence-based chemistry. I’d add that as chemists we need to make sure that this evidence is accurate. Dr. Jones and I don’t necessarily agree on our approach (we battle it out in #chemopocalypse, a podcast prosposed by @Chemjobber and had under the supervision of @ScienceIsntScary [link pending]) but I am 100% behind this idea.


Whether we have two terms to accurately define how people use the word chemical, is still insufficient to get chemists to act instead of react. In our pod cast, Dr. Jones warns that when we take on another term (say #chemsploitation) we run the risk of falling into the same attitudes as before. So as catchy as the catch phrases we have are, and whether or not we make sure to use them respectfully, they are still not inspiring action to reclaim the word chemical. Let’s retire them, accurately address the misconception and with taking back the word chemical.


Thus far @CompounChem’s marvelous info graphics are an excellent start. I enjoy them as a chemist and the non-chemists I’ve shown them to have loved understanding a little more about the chemicals that they enjoy every day (coffee, etc). They are a great way to start discussions. I am open to more ideas on how we can start educating folks about what chemical (and other appropriated words) really means, thoughts? What are some ways we can start doing this now? The more ideas we have, the merrier, and the more resources that we have to talk with different audiences. Do any non-chemists out there have suggestions for what they would like to see?

*The people that I refer to as doctors here have their doctorates or are close enough for me to respectfully add the title.
By February 10, 2014 6 comments chemical education

Rethinking the Jablonski Diagram

I am teaching a course titled “Spectroscopic Characterization of Molecules, Materials and Photovoltaics.” The first few lectures were on molecular photophysics and included a thorough introduction of the Jablonski Diagram (For anyone interested, my lecture ppt slides are available here).

The Jablonski diagram, first introduced by Aleksander Jabłoński in 1933, is a graphical depiction of the electronic states of a molecule and the transitions between those states. The y axis of the graph is energy, which increases from the bottom (ground state or S0) to the top (singlet and triplet excited states or Sn and Tn). The transitions between the states—like excitation, internal conversion, fluorescence, intersystem crossing, etc—are depicted as arrows. Because of its simplicity, the Jablonski Diagram is a starting point for many discussions about the events that occur following electronic excitation of a molecule.

Plain Jablonski

I am new to teaching and spent a lot of time thinking about what homework I should give my students to both facilitate learning and gauge their understanding of the content. An idea hit me when I saw Mark Lorch’s revamping of the periodic table to mimic an underground rail system.

We’re all familiar with the most common depiction of the periodic table because it’s hanging in every chemistry classroom on the planet. Yet, there is no inherent physical reason we have to map the elements in that particular way. The underlying motive for this common form is to show the periodic nature of the properties of atoms as defined by their number of protons. But there are many possible ways to fulfill that goal. Non-traditional periodic tables can provide a new perspective on the relationships between atoms that are not obvious in the traditional drawing.

With that concept in mind, I decided to ask my students to rethink the Jablonski diagram.

The exact wording of the assignment was to “draw a Jablonski diagram that includes singlet and triplet excited states.” I was hoping to inspire some creativity so I pointed to the periodic table on the wall and then showed them a number of non-traditional periodic tables. I even said, “If you can express the nuances of the Jablonski Diagram through interpretive dance I would love to see it.”

No one choreographed a dance, but I was still blown away by my students’ response to the assignment. Below are some of their awesome creations.

Here is one, by Tian Zhao, depicting the lowest energy species on top and increasing energy as you go down. I like to think that it is expressing the cyclic nature of the excitation/relaxation process under steady-state conditions.


This next submission, by Hadi Fares, is similar to the Bohr model of atoms and their electron orbitals that show the lowest energy state at the center and energy increasing outward. Unfortunately, this static image does not do justice to the animations he incorporated into the diagram.

Second image

This next diagram is similar to the one above but with additional artistic flare involving negative space. This aesthetic was inspired by “Vortex”, a game that Peilu Liu played on her ipod. The image got me thinking about the nodal planes of an orbital and whether or not it possible to graphically depict the likelihood of an electronic transition based on a comparison between the valence orbitals of a given state. Picture2

This final drawing, by Daniel Nascimento, really bumps up the information density of the Jablonski Diagram by not only including the energies of states and their transitions but also the approximate timescales of the events as shown on the x axis.


Much to my delight, a few students decided to really take a leap from tradition and make physical models of the Jablonski Diagram. Here is an ~12” tall work of art that was made by Maxime Matras out of aluminum rings—denoting the states (S0, T1, S1 and S2 from bottom to top)—and wires to denote the transitions between states (aluminum = excitation; copper = intersystem crossing, internal conversion, fluorescence and phosphorescence; coiled shavings = non-radiative decay).  This one now sits on my desk.

IMG_1655 small

 I even received a Jablonski diagram cake. The ground state, first singlet, second singlet and first triplet excited states are depicted in quadrants going clockwise (indicated by candy letters/numbers). The transitions are various colored lines of decorative frosting. What is really clever about this model is that the energy of the states are defined by their height from the pan. That is, the ground state is just a layer of chocolate frosting, the first excited state is a single layer of cake, and the second excited state is two layers. He also made the cake with tonic water in an effort to have it glow under a UV light. Unfortunately, I fear the cooking process destroyed the quinine and with it any possibility of glowing.  While not necessarily the most delicious of cakes, it was very creative.

 Cake image

And, finally, is “Jablinko!” This Jablonski diagram is based on the Japanese arcade and/or gambling game known as Pachinko. This photophysics-based game begins by placing a small metal ball into the S0 hole just above the lever. Pulling the lever, or exciting the molecule, shoots a ball to the top of the board into the singlet excited state. The ball (excited state) can fall one of three possible directions, NRD (non-radiative decay), ISC (intersystem crossing) or fluorescence. If it undergoes ISC, the ball can then fall into a potential well representing either non-radiative decay or phosphorescence from the triplet excited state. To top it all off, when the ball falls in to the fluorescence or phosphorescence holes it closes an electrical circuit that turns on a blue or red LED below the potential well. Those colors are the emission wavelengths for fluorescence and phosphorescence from anthracene.


In closing, I’d like to send a special thanks to my students. I have thoroughly enjoyed our time together and will always remember their clever responses to my first assignment.

By November 9, 2013 13 comments chemical education, fun

Substitution vs Elimination reactions: Guest Blogging at Master Organic Chemistry

A while ago, I invited myself over to James’ Master Organic Chemistry blog, and he has graciously allowed me to write a series of blog posts. Over the next few weeks, I’ll be guest blogging at James’ place about substitution vs elimination reactions – the historically confusing unit for undergraduate OChem students. Part 1 of 6 is live today. Head over to Master Organic Chemistry and check it out!

Part 1 of 6: You are my density, or why electrons are like a hyperactive child

By November 4, 2013 2 comments chemical education

A Short History of Proteins in Ink.

I teach a short course called Nature’s Robots (blatantly copying the title of Tanford and Renynolds’ book of the same name). It’s a potted history of protein science. I got bored of reading essays so I asked the students to create a short video on the subject instead.

One of thems produced this absolutely beautiful set of ink drawings.

In future I’ll just show students this video and sparing them my lectures!

By October 23, 2013 0 comments chemical education