The Gut, Microbes and Prebiotics

I read two engaging books last week (finishing both this weekend) that were very engaging. It was hard to put them down! Usually I try to read a chapter a day, but I was easily doing multiple chapters because I was hooked. I’ll write about the first book today since it is in keeping with my previous blog post on Making Visible the Invisible, except that instead of molecules it’s mainly about microbes.

The English translation of the book is titled “Gut: The Inside Story of the Body’s Most Underrated Organ”. The author, Giulia Enders, is a German student doing her Ph.D. in medical research. Giulia’s book came to be after she won a Science Slam (the video is fun and went viral!) based on her knowledge of gastroenterology. Giulia has a great sense of humor and it comes out in her writing. The book is accompanied by equally humorous illustrations with cartoons by her sister Jill.

There are so many interesting things I learned from the book. (If only more textbooks were like this!) Besides a journey through the digestive system culminating in the gut, a large portion of the book is dedicated to discussing the microbes in our digestive system. Who would have thought that gut microbiota could be so fascinating! While I had heard the statistic that the bacteria that live in us outnumber our cells by an order of magnitude, I did not realize how varied and interesting they are! They are also rather unique to the individual so I expect we’ll soon be having bacterial records similar to DNA records to identify perpetrators involved in criminal activity. There’s also a fascinating section connecting the gut and the nervous system – those “gut feelings” that you get, they might really originate in the gut. The gut might even be a second brain of sorts, at least the way Giulia describes it.

The last section on the book covers Antibiotics, Probiotics and Prebiotics. As someone with research interests in the chemistry of the origin of life, I use the word “prebiotic” in a different context. This is why I don’t tell people I study “prebiotic” chemistry, because then I would get asked all sorts of questions unrelated to my actual knowledge in chemistry. I did learn useful definitions for these three terms from the author. In particular, one can think of prebiotics as the nutrients needed to feed the “good” bacteria in one’s gut (i.e., the ones that don’t make us sick). Turns out that garlic and onions, two things that I love eating, are good prebiotics – as are several other vegetables that I also enjoy.

Some researchers in the origin-of-life or astrobiology fields look to extreme environments to examine how different “life” may have evolved possibly giving us clues as to what to look for when we send probes to other suitable planets or their moons. These unique “harsh” environments have a range of interesting microbes. But it turns out we don’t have to go very far to look for unique microbes – they’re living in our gut!

I highly recommend Giulia’s book – you’ll never look at your digestive system, gut, feces (yes, they are organized and classified!), microbes, or think about how what you eat is “processed” in the same way. And you’ll enjoy learning new things! What could be better?

Making Visible the Invisible

[Disclaimer: All images were grabbed by doing an image search on Google.]

As I’ve been teaching introductory chemistry to two different groups of students (science majors and non-science majors), I’ve been pondering how chemists use different representations to explain tiny things that we cannot see. A chemistry demo in class gives the viewer a macroscopic observation of a chemical reaction – the louder and brighter, the better! But the whizz-bang of the demo is merely a prelude, at least in the mind of a chemistry teacher, to the microscopic (or perhaps more accurately nanoscopic) description that “explains” the observation.

The modern expensive chemistry textbook is fully illustrated with colored balls and sticks connected to each other in a sometimes intricate arrangement. “Atoms First” is the current fad in chemistry textbooks. What this means is that the atomistic or molecular view takes center stage in the early chapters. Older textbooks had fewer pictures and started with macroscopic observations of chemical reactions but then used strange symbols and equations to represent them.

As a quantum mechanic who spends time thinking about the nature of the chemical bond, I personally like having atoms and molecules be front and center. However, picking a suitable model of the atom to describe the invisible (to us) particles can be challenging. It is clear that the heavily mathematical quantum model that I teach in an upper division physical chemistry course is unsuitable at the introductory level. In the non-majors class, we use the Bohr/shell model, not just for the hydrogen atom (where it works marvelously) but for every other atom in the periodic table where the simplistic model is actually wrong. It is however very, very useful. Students can get a feel for general trends in the periodic table and an atomistic level description of chemistry just using the shell model.

In science majors chemistry, we wade into atomic orbitals. This allows a finer grain description of atomic properties across the periodic table and a more detailed description of chemical bonds. The students are introduced to the “four quantum numbers” without much idea where they come from or why they are used. (An alternative approach that I have used ignores the numbers and makes use of photoelectron spectroscopy data.) We draw pictures of circles, dumbbells and cloverleafs alongside energy diagrams – and it’s a wonder that the students aren’t more confused as we throw a dizzying area of symbols and representations at them – all in an attempt to make visible the invisible.

Here’s an example. All my students recognize the symbolic formula for the water molecule, H₂O. (This is thanks to commercial product advertising, much more than chemistry classes!) Even without my telling them, I can project the following “space-filling” picture and they can all automatically tell me that it is a molecule of H₂O.

They have no problem recognizing the ball-and-stick model either. Do either of these pictures represent what a water molecule “truly” looks like? Why do we choose one representation over the other? (These are good questions to toss at students who often haven’t stopped to think about it.)

Here’s a shell model showing just the valence electrons.

Which can be “reduced” to the Lewis structure of the water molecule.

And after talking about Valence Shell Electron Pair Repulsion (VSEPR) Theory to predict molecular shape, we talk about “hybridization”. I’m pretty sure the students are rather clueless as to why we teach them this. (Some instructors may be clueless too.)

And if you were a Molecular Orbital aficionado you might show the students the following diagram from an Inorganic Chemistry textbook.

My students in both classes learn how to draw Lewis structures. In the non-majors class we talk about the principle of keeping electron clouds away from each other (explaining the difference between Pauli repulsion and electrostatic repulsion is not helpful to them so we don’t delve into it). I don’t use the term VSEPR theory since I want students to understand the concept and not try to memorize a fancy term.

In the majors introductory class, they do need to know the fancy term and we do discuss the qualitative difference between the aforementioned types of repulsion (although it’s unclear to me that all but the strongest students actually get the idea). Then I dutifully cover hybridization because we have many General Chemistry sections, and students are expected to have seen this before they get to Organic Chemistry. While I think I’ve managed to persuade most of my colleagues that d-orbitals hardly contribute to “hypervalent” molecules, it wasn’t until the textbooks (30 years late) started mentioning this in passing that I’ve seen instructors move away from using it. I do very little molecular orbital theory in my General Chemistry class even though it is “covered” in the textbook, although I do cover it in great detail when I teach upper division physical chemistry and/or inorganic chemistry.

We’ve got all these different representations to discuss the different properties of a single water molecule. But that’s not how any of us experiences water. We experience it in dollops of gazillions of molecules. Now clearly no one is going to draw a mole (6.022 x 10²³) of water molecules, the amount of water you might experience cupped in your hands.

Instead, we have pictures like the one below to tell us about the wonders of intermolecular forces! All represented by just five molecules.

Where am I going with all this? I don’t really know. But writing about it has made me more acute to the myriad ways that chemistry is represented. As an experienced practitioner, I see different symbols and my trained brain knows what information to extract from them and to cut straight to the salient points being illustrated. Students newly exposed to chemistry, on the other hand, do not have that advantage. I guess I’m trying to remind myself to be more judicious about the models that I use, to take wise advantage of the power of illustration, but to point out to my students why certain representations are being used and not to assume that the “picture tells a thousand words”.

Finally, I’m amazed by the ability of the human brain that conceptualizes all this abstract model with the aid of such pictures and illustrations. This is how we see that which is unseen. Through Art!

Wiley Pop: Harry Potter and History

I’m reading my first book in the Wiley Pop Culture series, Harry Potter and History. The book is a collection of fourteen essays juxtaposing the magical world of Harry Potter with its Muggle counterpart – our real world. I’m almost three quarters through the book. What I’ve gotten out of it is a combination of fun historical factoids and some historical-sociocultural analysis. I’ve learned about the making and use of parchment in the medieval world, the collecting of bezoars, witch hunts around the world in Muggle history, and Nicolas Flamel – a character spanning both worlds.

My favorite discovery came from an essay by M. G. DuPree titled “Severus Snape and the Standard Book of Spells: Ancient Tongues in the Wizarding World.” His essay begins with the sentence: “Language is the foundation of magic.” I had not noticed that household spells such as Scourgify had roots mainly in English, higher-order spells (e.g. Expecto Patronum or the Fidelius charm) were mainly from Latin, and that healing spells such as Episkey had their roots in Greek, the language of physicians. DuPree also discusses the origins of Hocus Pocus and its connection to the transubstantiation rites of the Latin Mass that may not have been well understood by the medieval farmer who did not understand Latin, as well as the ancient origins of abracadabra and its counterpart Avada Kedavra.

Several authors chose to compare institutions, ideologies and politics between the Muggle and Magical worlds. A timeline in the beginning of the book juxtaposes major events in both worlds allowing the authors license and creativity to speculate how events in one sphere influenced the other. One author discusses the formation of the Statute of Secrecy and its importance in reducing the oppression of witches and wizards. (It is interesting how the word “witch” today carries negative connotations, while “wizard” seems positively out of this world!) Another author examines the rise of fascism with Voldemort’s rise. One can draw parallels between pure-blood mania and Aryan nation ideas. Aristocracy and class distinctions is yet another subject of analysis, as is the comparison (and contrast) between the British political system and the Ministry of Magic.

From an educator’s point of view, it was interesting to learn the history of the British public school through the ages – in this case, the U.S. equivalent would be a New England private prep boarding school. The author Susan Hall does a masterful job of tracing the rise of Eton, Winchester and Rugby while weaving in the Slug Club, the early ideas of Dumbledore and Grindelwald, and even nuggets of how J. K. Rowling might have breathed fresh air into the flagging boarding schools of old. Smeltings (Dudley Dursley’s school) and Stonewall High (which Harry would have attended if not for his Hogwarts letter) are described and explained in the context of a section titled “Unfogging the British Education System”.

Besides the Wiley Pop Culture and History Series (of which this book is a part), Wiley also has a Blackwell Philosophy and Pop Culture Series. There doesn’t seem to be a Chemistry and Pop Culture series; my previous reading of Wiley books were much drier chemistry textbooks or research monographs. Maybe I need to pitch a Potions for Muggles book. But first I’ll have to write some sample chapters...

Private Doubt, Public Dilemma

Private Doubt, Public Dilemma – Religion and Science since Jefferson and Darwin, is the title of Keith Thomson’s book based on his 2012 Terry Lectures. Thomson is an emeritus professor of natural history at the University of Oxford. He has written a number of books that delve into the history of Charles Darwin and the formulation of the theory of evolution. Since I’m participating in a college-sponsored living learning community on Faith and Reason, I have been reading a number of books that address the relationship between science and religion.

Given my interest in history, I enjoyed Thomson’s approach to the topic. In ten short and very readable chapters, he covers the social milieu, both scientific and religious in the nineteenth century where various upheavals were taking place – in geology, biology, philosophy and theology. Thomson weaves a story spanning the U.S. and the U.K., starting with Thomas Jefferson but concentrating mainly on Darwin. The Aggasiz-Gray and Wilberforce-Hooker-Huxley debates in both countries are described with historical quotes and letters of the day.

The crux of Thomson’s argument comes in the ninth chapter “The Decline of Authority”. Starting with a personal experience of flip-flop instruction he received on Alfred Wegener’s continental drift, and following up with the discovery (and initial discounting) of Sherwood Roland’s connection between CFCs and the ozone hole, Thomson argues for the importance of context of what else was changing in the pivotal years close to 1860. (As an aside, the Karlsruhe conference that same year was pivotal for chemistry! For the historically-inclined, here's a translation of the session accounts.)

Thomson writes: “… with each [change in authority], new doubts arose as well as new certainties. Whatever conflicts may have risen or been acerbated between elements of science and religion in, say, 1860, they were part of a much wider picture of change. And in the process of change, leaders of both religion and science have had to think seriously about what their new roles should be. Perhaps not enough.”

He goes on: “Individual opinion always changes before authority. It is in the nature of authority to change slowly; society would be unstable otherwise. And religious authority may change slowest of all. The dilemma comes when change can no longer be put off.” Thomson thinks that the way forward is in areas where both science and religion have “joint ownership” and can benefit from cooperation for the public good. He provides one example: environmental stewardship. One wonders if there are more. Thomson also points out the weaknesses of the conflict avoidance approach by separating religion and science into two non-overlapping spheres of influence. The problem, he says, is that the “claims of authority of science and religion, do in fact, overlap, intersect, and compete with each other.” Therein lies the crux of the public dilemma – the issue of authority, when politics and power come into play, which has become to some extent farcical in the U.S.

In my first day of class on atomic theory, we discuss the issue of where we gain knowledge and the role of trustworthy authority when we cannot “check certain things with our own physical senses”. While there isn’t much about chemistry in Thomson’s book, I enjoyed a small section in one of his early chapters about atomic theory. He quotes the Greek atomist Democritus: “Nothing exists except atoms and empty space; everything else is opinion.” In class we discuss how this might sound crazy from the sensory perspective, but I didn’t have time to discuss why, as Thomson puts it, “such a philosophy was dangerous; atoms, chance, and necessity neither explained nor required free will.”

There’s a great Cicero quote (who probably drew from Aristotle), prescient of today’s monkey-typewriter-Shakespeare probability argument, against the atomists: “Must I not marvel that there should be anyone who can persuade himself that there are certain solid and indivisible particles of matter borne along by the force of gravity, and that the fortuitous collision of these particles produces this elaborate and beautiful world? I cannot understand why he who considers it possible for this to have occurred should not also think that, if a countless number of copies of the one-and-twenty letters of the alphabet, made of gold or what you will, were thrown together in some receptacle and then shaken out on to the ground, it would be possible that they should produce the Annales of Ennius. I doubt whether they could possibly succeed in producing a single verse.”

It’s worth quoting from the Bible book of Ecclesiastes (1:9): “What has been will be again, what has been done will be done again; there is nothing new under the sun.”

Grading Participation: Early Stage Evolution

I finished Jay Howard’s excellent book earlier this week. His second-to-last chapter, “Making Online Discussions Work” was insightful and echoed much of the good advice from Michelle Miller’s book. The topic of today’s blog is on the final chapter: “To Grade or Not to Grade? And Other Conundrums.” I am still a novice in trying to figure out optimal practices in my different classes. This post traces the evolution in my thinking so far. I recognize that I am still in the early stages – and there is far to go before I reach a robust approach. I’m very glad for the many others who have gone before, and this is an area where science professors have much to learn from our non-science colleagues.

Like many other “old school” science professors, I started with having problem sets and exams count towards a student’s final grade. Problem sets, which can be worked on collaboratively, take up a low percentage. Exams, with individual work only, took the lion’s share of the grade. I did not assign any credit towards participation nor did I take attendance. Students could choose to attend and participate, or not. The exams would determine if they understood the material. This is not to say that I had dry, boring lectures. My students over the years will attest to the fact that the classes are interactive, and I pose lots of questions to students (and I do wait for their answers). I also keep the material interesting in a variety of ways to help as a motivating factor for students to attend class.

In my first year teaching General Chemistry (before online homework systems had made their debut), I was over-zealous. Besides the Final Exam, I had five in-class hour-long exams, and every non-exam week there was a problem set. This was a killer from a grading point of view. The next year I cut down the number of problem sets and exams, but this meant that many students did not keep up with the material through longer stretches. (If you fall behind, it’s a lot of work to catch up.) It was only in my third year that I added frequent low-stakes quizzes – 5 minutes on an index card at the beginning of class. To start, I would give maybe 14 quizzes during the semester and count the top 8 (for 4% of the course grade).

The quizzes turned out to be a boon to keep students motivated towards learning while allowing me to reduce further the number of problem sets and assign ungraded homework. At that point I had not read much of the research literature on learning suggesting that this was a good strategy. Over the years I’ve given more quizzes per semester and had them count for slightly more. In fact, in one of my classes this semester that meets twice a week, I’ll be giving 20-24 quizzes and counting the top 16 for 16% of the course grade. This lowers the grade assignment due to exams. (Homework and problem sets have always hovered in the 10-15% range.)

Then came participation. The way I started assigning participation as a grade was when I got my first class of first-year advisees who were also in my General Chemistry course. The college had various useful “College Skills 101” workshops sprinkled throughout the semester such as study skills, how to choose a major, time management, staying healthy in college, etc. One of my colleagues required all the students in any of his classes to stop by his office at least once for a short chat early in the semester. I decided that this was a good idea and assigned 3% for the students to attend some skills events and stop by my office. Students wrote me one paragraph about their experience attending a particular “workshop” – what they learned, and whether they found it useful or not. (That way I could give feedback to Student Affairs so that they knew what worked well and what didn’t.)

These early efforts at assigning some grade towards participation did not involve any in-class participation towards discussing the course material. It is only in the last several years that I have started assigning a participation grade towards thinking about the course material. I have mainly done two things so far. One has been to incorporate blogging outside of class time for the students to connect course material with their lives outside of my chemistry class. The other is to assign short written assignments in class based on the course material. (I usually provide the prompt before class so students can think ahead, and there is usually some discussion both in small groups and as an entire class on the topic. Then the last 5-10 minutes of class is spent writing.) So far this has not been assigned more than 10% of the course grade.

I’ve tried to keep track of the quality of in-class discussion, roving from one small group to another, cold-calling a range of students (after they’ve had a chance to discuss things with their classmates of course), among other things. I just haven’t quite felt comfortable assigning a grade based on those interactions. It’s hard for me to keep track of them and to ensure equity. This is where the online component is helpful for keeping track of things, not to mention it also levels the playing field for students who may be much more introverted or who feel less comfortable expressing themselves in English if it is not their first language. Thank to Howard’s book, I’m now looking more into student self-graded discussion. This seems an intriguing way to possibly accomplish several goals but I’ll have to think about it a bit more before incorporating it.

At the moment, exams still form the bulk of the students’ grade. I think this is appropriate in some of the standard courses that I teach: General Chemistry and Physical Chemistry. However I can see some variation in other courses that I teach to reduce how much exams count towards the grade. I have much more to learn in any case!

Grit and the Age of Hufflepuff

This past week J. K. Rowling tweeted about the “dawn of the age of Hufflepuff”. As Hufflepuff Hippo, this sounds like exciting news – except of course I don’t really know what it means. There is some connection to the movie Fantastic Beasts and Where to Find Them, to be released in 2016. Newt Scamander, the main protagonist of the movie (and the book) hails from Hufflepuff house. Given that movies are often accompanied by merchandise, we might be seeing a lot more Hufflepuff paraphernalia. Now that’s something I can be excited about! Most things out there look Gryffindor-ish.

I find it interesting in our Internet-enabled age with social media tools like Twitter, that there is now an avenue for famous people to make a (sometimes cryptic) statement that then spark pages of electronic ink speculating on every aspect of even a single sentence. Rowling has become such a figure. Legions of fans seem to hang on to her every word – after all she has the author’s authority. (Makes you think about where the word authority comes from!) This isn’t necessarily a bad thing, as long as there is some critical thinking about what is being said by the authority figure. In the beginning of the semester, my class has a discussion about the existence of atoms (none of us has actually seen an atom) and how one obtains knowledge, and that learning by authority (as opposed to one’s own self-experimentation) can be a good thing especially if the author is trustworthy.

Let’s return to Hufflepuff for a moment. What are the traits of a Hufflepuff? Trustworthy, loyal and kind, dedicated, hardworking, patient, etc. Those sound like great traits! (For another assortment, see Buzzfeed’s 19 Reasons Everyone Should be a Hufflepuff, which also makes use of Twitter pronouncements by Rowling.) Sounds like it beats just being ABC: Ambitious, Brave or Clever. (As Hufflepuff Hippo, I am clearly biased.) The trait I have been thinking about this week, that applies well to Hufflepuffs, and that my students should hopefully learn, is Grit.

Grit makes one think of tenacity, a willingness to work hard to overcome obstacles, and having fortitude. As I’ve been thinking a lot about teaching and creativity lately, this reminds me of the oft-quoted Thomas Edison phrase: “Genius is one percent inspiration and ninety-nine percent perspiration.” If you equate creativity with genius (I’m not sure it is – but the two often get conflated), then it sounds like a helluva lot of grit is required. Another common phrase associated with creativity, specifically openness to new ideas, is Louis Pasteur’s “Chance favors the prepared mind.”

Much ink (both physical and electronic) has gone into examining whether grit and creativity are linked. Views vary widely across the spectrum as to how integral grit is to creativity. As both a teacher and a learner of new things, I experience firsthand the importance of grit in trying to accomplish a challenging task whether it be putting together a well-timed and coherent class activity that meets all the ambitious learning goals, or surmounting a roadblock that has stymied a research project. There is a temptation to do less than the best – and honestly I don’t always do my best. But having experienced the value of putting in the hard work and seeing the fruits of that labor are satisfying when it involves something I am interested in or care about.

There’s the rub. I think that grit leads to its best results in creativity and excellence when it is something you really do care about. Given that I care about my teaching, and the learning of my students, I’m quite willing to put in the work to get better and be more creative at it. In the parlance of the creativity literature, I’m intrinsically motivated. But not all my students are interested in chemistry. Many are there because it’s a requirement they have to fulfill but they show little interest in. They are extrinsically motivated. Grit now becomes a painful (“grit your teeth”) process that you just need to get over and then you can go on with the rest of your life, rather than a part of creative and excellent work.

I had an open and lively discussion in my chemistry for non-science majors class last week, where the students were free without repercussion to articulate how they are apprehensively viewing taking a chemistry class. (We structured the discussion around the question “Why is there little understanding of science among the general public?”) I was able to articulate why I specifically choose to teach this class year after year. (I don’t have to, and in fact could go through my career not teaching it.) I told the students that it is my hope that they will find chemistry both interesting and applicable to their lives, but they will have to work hard to understand it and that it will be worth the time and effort. I’m not sure everyone believed me, but that’s okay. (I also happen to teach Physical Chemistry – the dreaded class of Chemistry majors, where similar conversations take place, often in my office over problem sets.)

In the “old school” days, learning could be a torturous and gritty exercise. There are trends and pressures to “make things interesting and relevant” (which is not a bad thing) today but hopefully we don’t lose the importance of grit. Spoon-feeding our students (and many of them seem to want the “easy way”) is doing them a disservice. They need to learn to grapple with the difficulties – but it is incumbent upon us as teachers to improve how we motivate our students without watering down our expectations. Now that could be creative teaching in a new age of Hufflepuff!

Teaching for Creativity Part 2

I finally finished Nurturing Creativity in the Classroom, a collection of essays I described in my previous post. There were some good articles towards the end of the book. One was the long and comprehensive “Intrinsic Motivation and Creativity in the Classroom” by Beth Hennesey, which delved into the research connecting intrinsic and extrinsic motivation with creativity. While much of the research in the book discusses K-12 education, Diane Halpern’s chapter “Creativity in College Classrooms” highlights the connection between critical and creative thinking, and discusses the use of technology to facilitate creative activity.

The final essay was written by one of the stalwarts of the field, Robert Sternberg in the simple title “Teaching for Creativity”. His prose is lucid and very quotable. Here are my three favorite sections (the first is actually the opening paragraph):

“Creativity is a habit. The problem is that schools sometimes treat it as a bad habit. And the world of conventional standardized tests we have invented does just that. If students try being creative on standardized tests, they will get slapped down just as soon as they get their score. That will teach them not to do it again.”

“Like any habit, creativity can either be encouraged or discouraged. The main things that promote the habit are (1) opportunities to engage in it, (2) encouragement when people avail themselves of these opportunities, and (3) rewards when people respond to such encouragement and think and behave creatively. You need all three. Take away the opportunities, encouragement, or rewards, and you will take away the creativity. In this respect, creativity is no different from any other habit, good or bad.”

“Society tends to make a pedagogical mistake by emphasizing the answering and not the asking of questions. The good student is perceived as the one who rapidly furnishes the right answers. The expert in a field thus becomes the extension of the expert student – the one who knows and can recite a lot of information. As John Dewey recognized, how one thinks is often more important than what one thinks. Schools need to teach students how to ask the right questions (i.e., questions that are good, thought provoking, and interesting) and lessen the emphasis on rote learning.”

I must admit that when I first stated teaching, Sternberg described me very well as someone who emphasized the answering rather than the asking of questions. And yes, I would label the “good” students those that quickly and accurately provided the “right” answers. That tells you something about the narrowness of my questions and perhaps the level in Bloom’s taxonomy in which I was engaging the students. More recently, over the past several years, I’ve tried to change the way I ask questions. There’s nothing wrong with asking some of the lower-level Bloom questions – in fact they’re crucial to get everyone on the same page. But the teacher should not stop there, and neither should the student.

Yesterday, we were covering measurements and units in one of my classes. I planned several activities for the students to engage in to illustrate the key concepts. We started off with them trying to identify me as a perpetrator in a crime (guesstimating height and weight). This led to a discussion about how to calculate averages and when to use an arithmetic average, followed by discussing precision and accuracy, sources and types of errors, and how one makes measurements and calibrates a reference point. Then I used Archimedes’ Eureka moment by posing a number of questions both to get the students to think creatively and how to design an experiment. We calculated what the difference in water displacement might be between a solid gold crown and an alloy. (The quantity is much smaller than the students expected therefore requiring being creative about experimental design to measure as precisely and accurately as possible.) We then talked about the density of water, and I posed the question “How dense are you?” (to student chuckles) and talked about how you might estimate, calculate or measure your own personal density including methods that allowed you to stay dry during the measurement. This then led to a discussion of BMI (Body Mass Index). We did unit conversions, talked about S.I. units, and covered scientific notation.

I enjoyed the class. Hopefully the students did too – they seem engaged at least, although now that I know about the Norm of Civil Attention from Jay Howard’s book, maybe it’s not so easy to tell. Next up is delving into the structure of the atom, and reinforcing how science asks and answers questions.