This might just be my new favorite book about teaching…

Last month, I bought and read Terry McGlynn’s excellent new book, The Chicago Guide to College Science Teaching (published 2020). It is one of those books that hits the rare combination of being informed by educational research without dwelling on the minutiae or jargon of that research. (A few years ago, I wrote a blog post about my other favorite teaching book, Saundra McGuire’s excellent Teach Students How to Learn.)

What do I like about McGlynn’s book? Most importantly, it’s practical. It’s not exactly a “How to Teach” guide, because as the author acknowledges, each of us has different goals, different personalities, different classrooms, and different constraints. Instead, the book presents an easy-to-read narrative describing ways to implement what he calls two keystones: Efficient Teaching and the Respect Principle.

“Efficient teaching” is the idea that we can all spend more time—and more, and more, and more time—crafting an ever-more-perfect class. But will that added effort produce a proportional improvement in student learning outcomes? If not, perhaps it’s time to repurpose some of that polishing time into making larger changes that yield a bigger payoff.

Implementing the “respect principle” means setting aside the idea that students are dishonest or that they are constantly trying to exploit loopholes in our course policies. It means choosing trust instead, and actively dismantling class policies that reinforce a culture of mistrust. The author challenges readers to develop policies that are fair to all students, regardless of their individual circumstances and obstacles. In short, he likes to think of teachers as coaches, not adversaries.

Interested? Well, you’ll be happy to know that I’ve summarized only the first 13 pages! Those pages make up the first part of chapter 1, “Before you meet your students.” Subsequent chapters provide useful suggestions for the syllabus (chapter 2), the curriculum (chapter 3), teaching methods (chapter 4), assignments (chapter 5), exams (chapter 6), common problems (chapter 7), and online teaching (chapter 8).

This book gave me a lot to think about. Here are a few of my other main takeaways:

Make Class Policies More Flexible. I learned that inflexible class policies make life hard for today’s students in ways that many of us “old-timers” may not even think of. College is way more expensive than when we were in school, and lots of students work a lot of hours at low-paying jobs—not to mention caring for kids and/or ailing parents, facing technological challenges, spending time in long commutes, being sidelined by car troubles, and so on. Why not add some breathing room by dropping a few low scores in some assignment categories, or by reducing late penalties? Next time I work on my syllabus, these issues will be at the top of my mind.

Be More Accommodating: I also have been thinking about “services” that I offer outside of class, like office hours, review sessions, and supplemental instruction. Students can and should be held responsible for attending classes as listed in the schedule. But when it comes to out-of-class activities, how can we accommodate students who are unable to attend because of class conflicts, work schedules, or family responsibilities? I confess that I have considered my own convenience more than my students’ needs in offering office hours and weekly supplemental instruction. If a student wanted to attend but was unable to, well, that was too bad. I rationalized that these activities were “extra” and therefore not strictly required for success in the class. Now I see there’s a better way, as I outline below.

Record Review Sessions and Supplemental Instruction: The COVID-19 pandemic has greatly expanded opportunities to offer review sessions and supplemental instruction online, even for in-person classes. Putting them online should reduce barriers for students who cannot physically attend. The recordings can then be made available for all students to view at their convenience.

Better Office Hours: I think online office hours will also be in my future, along with more frequent reminders of what office hours are, how students can benefit from using them, and how to make appointments when my office hours don’t match up with a student’s schedule. I may even require students to sign up for a brief meeting at the start of the semester so I can talk to them one-on-one. That way, maybe it won’t be so scary for them to ask for an appointment later in the semester.

Anyway, this book has so much good stuff in it that I couldn’t possibly summarize it all here. If what I’ve described here sounds good, I encourage you to buy the book or see if you can get it at your local library. If you are open to new ideas about teaching, I think you’ll be glad you did.

P.S. As I was looking up the publication date for McGlynn’s book, I noticed that it is part of a series called “Chicago Guides to Academic Life.” Other titles in the series include What Every Science Student Should Know and How to Succeed in College (While Really Trying) and 57 Ways to Screw Up in Grad School. There are lots more, too. If they’re as well-done as McGlynn’s, they’re probably worth a look.

Seven Strategies for Sustaining Student Engagement Online

Thanks to an extremely well-timed sabbatical, I have not had to teach my nonmajors biology class during the COVID-19 pandemic. But I have paid attention to what my colleagues are doing with their classes, and I have read a bit about best practices. I am especially interested to find out which pandemic-era teaching practices will remain when normal life returns.

Illustration source: https://pixabay.com/illustrations/webinar-conferencing-video-call-5310229/

I know that pandemic teaching has necessitated new strategies for maintaining student engagement, which is a challenge that I ponder even in the best of times. For example, in one previous blog post, I wrote about the benefits of random calling, and in another, I wrote about Kimberly Tanner’s excellent article describing 21 teaching strategies that promote engagement and cultivate equity.

A great companion to these articles just appeared in CBE-Life Sciences Education. The new article, by Daniel L. Reinholz and colleagues, is called A Pandemic Crash Course: Learning to Teach Equitably in Synchronous Online Classes. It describes a situation that will feel familiar to anyone who was teaching in spring 2020: The rapid and unexpected mid-semester shift from face-to-face to online instruction. In this case, the “students” were instructors who were participating in a professional learning community focused on equity. That is, the instructors in the learning community were meeting face-to-face to discuss equitable teaching in their face-to-face classes… and when their own classes went virtual, the instructors’ learning community did, too.

The article contains a lot of details about how the participants used a classroom observation tool called EQUIP, but that’s not what I want to highlight here. For me, the most interesting part comes near the end, in a section called “Strategies for Promoting Equitable Participation.” The authors recommend seven strategies, which I have listed (and commented on) here.

1. Re-establish norms: In face-to-face classes, you may or may not articulate the “rules” of the game, but students quickly come to understand whether, when, and how to ask questions or participate in the discussion. In a virtual classroom, students need to know whether to use Chat, or Q&A, or raise their actual hands, or just interrupt with a question, and they need to know how you are going to decide who to call on. Clarifying the rules will place everyone on equal footing from the start.
2. Use student names: This is, of course, a good practice in any classroom. One of Zoom’s big advantages for teaching is that everyone’s name is visible on screen, so you don’t have to spend time memorizing names as you might in your face-to-face class. Using names, especially to call on those who have been quiet during a class session or to reinforce a point that a student made during a discussion, helps students feel “seen” and signals that you value their participation.
3. Use breakout rooms: I have little experience with breakout rooms, but the authors of the article say that students who might be shy about speaking up in the “big class” will be more willing to participate in a smaller discussion group. You might consider popping in on the breakout rooms and then, when the whole class comes back together, calling on students by name to share some of the interesting ideas you heard them discuss in their small groups.
4. Leverage chat-based participation: A lot of students would rather type into a chat than speak up. Depending on the size of your class, keeping an eye on the chat while you’re juggling your other responsibilities may be overwhelming. In online classes I’ve observed, a teaching assistant has monitored the chat sidebar, typing answers to questions that pertain to individual students and alerting the instructor about issues that need clarifying for the whole class. If you don’t have a helper, then consider taking periodic breaks to skim through the chat. You can then call on students to talk out loud about the comments they typed in. Or you can bring up selected issues that you see in the chat, which will demonstrate that you are listening and responding to their questions and concerns.
5. Using polling software: Having students answer questions can liven up any class, whether face-to-face or online. If you don’t want to grade responses, then you can use the informal polling using tools built into Zoom or whatever online course delivery platform you’re on. If you want to grade the responses, then you can use applications like Poll-Everywhere or Top Hat or a similar cloud-based system—but then, of course, you will have to deal with the student registration problems that will inevitably arise.
6. Create an inclusive curriculum: According to the authors, “Equity in a classroom is… reflected in… how an instructor validates different ideas, identities, and cultures (e.g., through the choice of course content, through the use of affirming language).” Part of the idea is for all students to feel welcome to bring their personal experiences into the classroom. I confess that in my own nonmajors biology class, I have been so focused on explaining the core scientific ideas that I have neglected the social implications of biology, as well as my students’ unique reactions based on their own experiences. I am only now waking up to the idea of exploring these avenues as a way to boost inclusiveness and equity, so I don’t have much concrete advice to add—at least not now.
7. Cut content to maintain rigor: I am genuinely excited about nearly every topic in my nonmajors biology class, so it’s been hard for me to cut content over the years. However, I have also been thinking lately about what my students are missing, such as in-depth discussions about scientific topics that are relevant to their lives. In the words of the authors, “one of the barriers to equitable participation was simply trying to do too much in a course rather than doing fewer things well.” Hear, hear… now to figure out how to do it!

Finally, I appreciate Matt Taylor for offering one more suggestion from the perspective of a student who has been taking online classes during the pandemic. He suggests allowing students a lot of flexibility to complete coursework on their own schedule. Instructors are struggling to balance many competing demands during the pandemic, but so are students. Flexibility shows that you see your students as humans. It also doesn’t hurt to be liberal with your praise for what your students are accomplishing during a super stressful time.

I hope this list gives you something to think about as you plan next semester’s courses, which will almost certainly have an online component. Remember, when looking at any list of strategies, it’s important not to get overwhelmed by all the things you COULD do. Instead, look through the list and pick one strategy to focus on first. See how it works, get comfortable with it, and if you’re ready for another challenge, take the next bite. I am sure I am not alone when I say that I am eager to learn what you try and how it works—so please, leave a comment!

A New Way to Look at Red-Green Colorblindness

When we cover genetics in our nonmajors biology classes, many of us use red-green colorblindness as a familiar example of X-linked inheritance. We may even ask our students to indicate whether they can see the numbers or symbols in Ishihara plates. (For privacy, we’d ask via anonymous clicker questions, of course.) If our classes are large, we may even be able to demonstrate that more males than females are red-green colorblind.

Image of Ishihara plate from Wikimedia

For those of us with “normal” vision, however, it may be hard to understand what the world looks like to people with red-green colorblindness. I admit that I never thought much about it until I saw these two short videos, posted by the University of Oklahoma’s Fred Jones Jr. Museum of Art.

Screen capture from Part 2 of the colorblindness video.

At this point, you may be wondering what red-green colorblindness has to do with art museums. Well, our art museum created these videos to publicize their recent purchase of colorblind correction glasses to loan to museum patrons. The videos follow two colorblind students who are using the glasses while exploring the museum, seeing for the first time what red and green look like to most people. The videos are brief, funny, and enlightening, so I recommend them for use in your classes.

You can stop reading here if that’s all you want; it’s where I would have stopped if I hadn’t started digging a little bit more into how colorblind correction glasses work. I learned that the glasses are made of special materials that block out the specific, overlapping wavelengths that make it difficult for colorblind people to distinguish between red and green.

So … do they work? According to the American Academy of Ophthalmology, the answer is “it depends.” That’s because the form and severity of colorblindness makes a big difference in whether the adjusted wavelengths actually help a patient differentiate between red and green. The glasses also have some limitations: They are expensive, and they block some of the light entering the eye, meaning they should not be worn while driving.

I also found an article suggesting that the glasses may not be all they’re cracked up to be. That article summarizes research published in a journal called Optics Express. Not surprisingly for a journal about optics, the contents of the article are on the technical side. Nevertheless, the article contains many data tables, one or more of which students could analyze to draw their own conclusions about whether the glasses work as advertised.

If you want to use this topic to teach about scientific thinking instead of as a quick genetics lesson, consider having your students watch the art museum’s videos, look at some websites that promote colorblind correction glasses, and then evaluate the strength of the promotional claims and/or the strength of the Optics Express study’s conclusions. If you do, please leave a comment to let me know what you did and how it worked!

“BiteScis”: Bite-sized research to promote scientific thinking

Are you looking for biology lessons that promote scientific thinking, are classroom-tested, and are fully customizable to your own needs? On second thought, who isn’t? While reading The American Biology Teacher recently, I learned about a good source: BiteScis, a website with lesson plans that “make it easy for teachers to share exciting, creative, and authentic science research with their students.” BiteScis has existed since 2015, so I am a little late to the party, but it’s never too late to share a great resource.

Lessons are available for biology, chemistry, physics, and earth science. Of course, I gravitated toward the biology section. I found eight lessons tagged as “Classroom Tested!” plus two more labeled “Beta Test Me!” Most are focused on evolution, including antibiotic resistance, convergent evolution in animal locomotion, homologous gene expression in mammals, mismatch diseases, HIV evolution, and more. (I later discovered that many of the lessons that aren’t classified under the Biology topic nevertheless have a life sciences component, including animal navigation, bioluminescence, kinematics, swimming dolphins, and coral reefs. So I recommend that you don’t narrow your search too much.)

I didn’t see anything I didn’t like, but my favorite lesson was “From Lab to Newsfeeds: Why We Need To Be Skeptical (Like a Scientist) In The Age of COVID-19.” It is one of the two available for beta-testing, and it does not yet have a full suite of student resources. However, there’s plenty there for instructors who want to try it out. If you click on the site, you’ll see a short introduction, accompanied by links to a PDF and an editable Google doc of the “Bite.”

The Science Bite is a 5-page document explaining why science has never actually worked as depicted in the familiar diagram of the simplified “Scientific Method” (question –> hypothesis –> experiment –> data –> conclusions –> repeat). The Bite then goes on to describe how the COVID-19 emergency has promoted a “new normal” of research being rushed into publication while social media platforms hype results that haven’t necessarily been peer reviewed. Fortunately, readers are not left to flounder helplessly in a sea of misinformation. Instead, the Bite includes tips for recognizing real science and, at the end, it provides five “Thinking Questions.” The questions are open-ended and thought-provoking, and they could lead to fruitful classroom discussions.

The second lesson plan I checked out was “Evolution and E. coli: Natural Selection in a Stable Environment.” That one included a Bite plus a student handout; I couldn’t see the Educator portion, which requires login credentials. The Bite is about a long-term experiment in which researchers have tracked mutations and fitness in E. coli cells in a stable environment for a mind-boggling 60,000 generations. I loved the student handout, which walks students through questions about alleles, competition, reproductive success, natural selection, data interpretation, speculation about alternative outcomes, predictions, and more. The level was not too hard, and not too easy—it was in that hard-to-find “just right” Goldilocks zone. (If you disagree with that assessment, no problem. The Google doc version of the student handout is easy to modify to suit your students’ needs.)

The website says the activities are designed for high schoolers, and the lessons are aligned to NGSS and Common Core state standards. As someone who teaches nonmajors biology to college students, however, I can attest they are perfectly appropriate to university-level introductory biology classrooms as well. Next time I teach my nonmajors biology class, I expect to give my students a taste of BiteScis resources.

What Does a STEM Professional Look Like? One Graduate Student’s Perspective

Photo courtesy of Montrai Spikes

I encourage you to visit today’s Science Careers website and read the moving commentary entitled Why I’ve struggled with the pressure to assimilate when teaching. The author is Montrai Spikes, a graduate student in Biology at the University of Oklahoma (where I teach).

Trai writes that as a teaching assistant, “the mask [that he] crafted” to appear “professional” to his white students had the unintended effect of “alienating students of color.” He ends by inviting us to discard our preconceptions about what it means to be a professional. His observations were enlightening to me, and I think they deserve to be widely shared; I hope you will read his commentary and distribute the link to your colleagues.

Calling on students at random: What are the keys to success?

Photo credit: Wikipedia

Lofty principles of equal opportunity guide our country and our schools, but the truth is that not everyone is treated fairly, and not everyone’s voice has an equal chance of being heard. As instructors, we must confront the painful idea that our own teaching practices can unintentionally reinforce inequality. I am therefore attracted to people who approach this problem thoughtfully and offer constructive suggestions for improvement.

A while ago, I wrote a blog post about an excellent and still-timely article that lists an impressive variety of ways to promote engagement and equity in the classroom (Structure Matters: Twenty-One Teaching Strategies to Promote Student Engagement and Cultivate Classroom Equity, by Kimberly D. Tanner).

One of my favorite strategies from that article was to call on students randomly instead of waiting for volunteers to answer questions directed to the class. Since I read that simple tip for boosting participation and encouraging diverse voices, I have used it in both my medium-to-large nonmajors biology class and in my small science writing class aimed at graduate students. In short, I like it.

Recently, I was interested to read a new article from CBE–Life Sciences Education devoted entirely to random calling. The authors, Alex H. Waugh and Tessa C. Andrews, recognize that random calling has benefits and costs. Even among instructors for whom the benefits outweigh the costs, they don’t necessarily agree on how best to implement random calling. So Waugh and Andrews interviewed 12 instructors who use this technique in an effort to find the “critical components” that are essential to success. If you want all the gory details, I urge you to read the full article. But for those of you who just want the take-home message, here you go.

According to Waugh and Andrews, the critical components of random calling are:

• Explaining to students why you are using this technique in your class, emphasizing the benefits and detailing how you are minimizing the potential costs;
• Allowing students to discuss a question among themselves before randomly calling for an answer;
• Calling on a group, as opposed to an individual student;
• Allowing a student to report the group’s collective ideas rather than their personal thoughts;
• Being “respectful and polite” (I might add here, editorially, an enthusiastic thumbs-up for this piece of advice).

The 12 instructors were divided on the finer details of implementation, including whether each group should assign a reporter role ahead of time vs. allowing an outspoken group member to volunteer information on behalf of the group. Another area of controversy was whether random selection should be with or without replacement – that is, once a student or group has been called on, is that student exempt for the day/week/rest of the semester, or might that same name be called again? In addition, a few instructors allow students to “pass” on a question; a few others allow students to put themselves on a “do-not-call” list. The article explores all of these issues in detail.

The article does not touch on random calling in online classes, but I am writing this blog post in the midst of the COVID-19 pandemic, so I have been thinking about which of my favorite teaching techniques lend themselves to teaching online. In a synchronous online class, e.g. on Zoom, I don’t see any reason why an instructor couldn’t call on an individual student at random. If the Zoom class uses breakout rooms, the instructor could also call out groups randomly when the class as a whole reconvenes. I would love to hear (in the comments section) from instructors who have relevant experiences to share.

If you have not yet tried random calling, I encourage you to do so. If you have tried it but want to know more, take a look at the Waugh and Andrews article. Either way, keep an open mind about your longstanding practices as you think about how you can be part of the solution.

Reference:

Alex H. Waugh and Tessa C. Andrews. 2020. Diving into the Details: Constructing a Framework of Random Call Components. CBE–Life Sciences Education, vol. 19, no. 2. https://www.lifescied.org/doi/full/10.1187/cbe.19-07-0130

Instructors: Be kind to your future self

I’ve posted a few times on helping your students cultivate a growth mindset. But I think its also important to think about our own mindsets as instructors. How can we cultivate a growth mindset about teaching, learn from our mistakes, and make our courses better each semester? I have a couple of suggestions.

Read my previous posts about the growth mindset: At the End, I’m Looking to the Start and Cultivating a Growth Mindset in Your Students.

My first suggestion for instructors is to pay attention to what works and what doesn’t during each class session. Then, right after class is over, put a note to future self in your PowerPoint presentation. The note should be obvious, so you don’t miss it, and it should include the date you wrote it. Something like the PowerPoint slide below:

 

A second idea is to ask your students two questions during a class leading up to an exam. One is “What is the most interesting thing you have learned during this portion of the semester?” That question is a favor to your present self because it helps reassure you that at least something was interesting, despite the sea of expressionless faces that greets you each day. The second question is, “What is something you still don’t understand?” You can sort the answers by frequency and use them to formulate a review session before the exam. But they are also a favor to your future self because those answers can reveal where you can improve your teaching. For me, bond polarity and hydrogen bonds frequently top the list of topics students don’t understand before exam 1. I have therefore worked very hard to improve my approach to those topics.

I have one more suggestion for a way to be kind to your future self, and it pertains mostly to instructors who teach classes that meet once a week for several hours. My writing class fits that format, and it’s a challenge to plan out the three hours such that the pace is not too rushed and not too slow. One suggestion is to make a plan on paper for each class, e.g., from 4:30-5:15 we’ll recap their homework, readings, and other assignments for the past week, from 5:15-6:00 we’ll do peer review, at 6:00 we’ll take a 10-minute break, and so on until class ends at 7:20. During class, note right on the paper how long everything actually took, along with observations about what worked and what didn’t. After class, take a picture of the paper and insert the photo into your class PowerPoint. Next time you teach the class, you’ll have a better idea of how to adjust your strategy. Trust me when I tell you that your future self will thank your past self for taking a few minutes after class for this task.

Instructors, in what other ways are you doing favors for your future self? Leave a comment to let us know.

My Students Need Help Asking for Help; Do Yours?

We finished exam 2 in my nonmajors biology class last week, and after the exam was over, I had an epiphany: Very few students asked me for help.

For context, I’ve been doing this job for more than 20 years. Years ago, on the night before an exam, I would have to warn students to email me questions before 10 pm because after that I’d be in bed. I’d host popular online chat sessions near exam times, and my Action Centers would see a lot of (ahem) action. Students would ask me to recommend tutors. On exam days, my office would be crammed with students asking for last-minute help. Now: crickets. No student ever emails me a question about course content or asks about tutors. A handful of students come to Action Center, and my office hours remain empty, even on the morning before an exam.

The Internet is full of articles about why students don’t use office hours. The reasons are interesting, but they’re missing information about trends. Why did students ask for help in the past, and now they don’t? Let’s rule out a couple of possibilities right off the bat. First, have I become such a fantastic teacher that none of my students need help? Nope, it’s not that, as the range on exam 2 was 39.5 to 97.5, with an average of 71. That adds up to a lot of students with sub-par performances. Second, am I meaner and more intimidating now than I was when I was much younger? Sure, that’s possible, but I certainly bend over backwards to be approachable and to remind students of how to get help.

It’s hard to test hypotheses about how students have changed over the years without hard data, so I decided to ask my students why they don’t seek help. I used a not-for-points clicker question:

If you were struggling in a class (any class, not this one in particular), what would be most likely to keep you from seeking the professor’s help? Mark all that apply.
Feel free to switch clickers if you don’t want me to connect you with your answer.

A. I don’t have time to get help.

B. I get help from my friends; I don’t need the professor’s help.

C. I’m afraid I’ll look stupid if I ask for help.

D. I’m too intimidated by my professors to ask for help.

E. I’m so overwhelmed that I’m not even sure where to begin asking for help.

F. If I’m not naturally good at the subject, then seeking help wouldn’t do any good anyway.

G. It’s stressful to confront failure, so I procrastinate.

H. Other

Students could choose as many options as they wanted. Have you already predicted which choices received the most votes? Go on, do it now. I know what I thought they’d say: They don’t have time (choice A), they’re too intimidated (choice D), and it wouldn’t do any good anyway (choice F). Well, I’m glad I asked instead of making assumptions. The graph below shows the number of votes that each choice got:

What really hit me hard about the results is that students admitted to the pain of confronting failure (choice G), to being overwhelmed by the challenge of seeking help (choice E), and to being afraid of looking stupid (choice C). I am no psychologist, but I feel sure there must be tools that can help students overcome these challenges, and I plan to look for ways to identify and recommend such tools in the future.

Choice H, “Other,” bears special mention as well because it was tied for third in the voting. I emailed the students who had selected it to find out what I had missed in crafting my question. Each of those who replied had a different reason for choosing H. One prefers to go to a tutor before bothering a professor. Another battles anxiety and depression and would find it difficult to approach a professor for help. Another isn’t sure what kinds of questions (content or policies?) one is supposed to ask in office hours. Another has had professors in the past who seemed annoyed when students came to office hours. Yet another likes to do things alone and therefore prefers not to ask for help.

My big takeaway from this question is that I need to help struggling students to be brave about asking for help. But am I offering the right formats? My followup question, in the next day’s class, aimed at that issue:

If you were to seek a professor’s help, how would you prefer to get that help? Mark all that apply.

A.One-on-one in professor’s office (in-person office hours or by special appointment)

B.Come-and-go “study time” with professor at a location outside professor’s office (without prepared activities)

C.Come-and-go Action Center (with prepared activities)

D.Email questions to professor

E.Online chat (virtual office hours or appointment)

F.Post questions to professor on Canvas discussion board

G.Informal group discussion with professor present at a neutral location, like a coffee shop

H.Other

Take a moment to predict what you think students said. I predicted a strong preference for virtual office hours (choice E) and perhaps the Canvas discussion board (choice F). This graph shows what they actually said they preferred:

When I saw the results, I thought to myself: “Wait, what!?” In-person office hours (choice A) and Action Center (choice C) are the two main types of help I’m already offering, and few students take advantage of them. Having group discussions and study groups at a neutral location also got a lot of votes, and those are two things I might consider in the future. Bringing up the rear were the options I thought students might like because they don’t require face-to-face conversations, such as emailing questions (choice D), the Canvas discussion board (choice F), and online chats (choice E).

According to these graphs, if I want my students to get the help they need, then I need to find ways to help them overcome the psychological barriers that keep them away from office hours and Action Center—both of which many say they want yet few are using. This predicament raises interesting side questions: How much of this is on me to solve, versus the students learning for themselves to be brave and conquer their fears? Stated another way, do changing student habits reflect a cultural shift that I need to adapt to, or should I tell my students to pull on their big kid pants and get over it?

I haven’t had time to think these issues through, but I will be ruminating on them in the coming weeks. In the meantime, I welcome your comments, especially if you have noticed this phenomenon too and have found new ways to help your students get the help they need.

The Incredibly Stretchy Condom, Revisited

It has been about 6 years since I wrote about the “Process and Tools of Science” lab in which students learn metric units of measure while they experiment with condoms. I still love this activity and use it every semester, but recently I heard of two possible enhancements, and I pondered how to elicit improved experiments from our students. Perhaps some of my readers will benefit from my recent experiences.

The enhancements come from Dr. Sehoya Cotner, an energetic and fearless professor at the University of Minnesota. In the summer of 2019, she led a workshop for the Association for Biology Laboratory Education, my favorite professional organization. (I cannot recommend it enough; check it out if you teach biology labs at any level.) The workshop covered several labs from her Evolution and Biology of Sex class, and I was thrilled to see the condom experimentation lab among them.

I was even more thrilled when I was randomly assigned to the condom experiment during the workshop. I was excited because she added two twists that I hadn’t thought of. One was to add condoms made of “natural membranes” (intestines) to the usual mix of latex and polyisoprene condoms. The natural ones are super expensive, and while they prevent pregnancy, they don’t protect against sexually transmitted infections (STI). Cotner taught us that green food coloring particles are larger than HIV and other viruses but smaller than bacteria and sperm. So our group designed an experiment in which we dispensed a known volume of green food coloring into natural condoms, latex condoms, and polyisoprene condoms, then dunked all of the condoms in a known volume of water. The idea was to time how long it took for green food coloring to become visible in the water. It worked fabulously well.

Trustex (latex) condoms are impermeable to green food coloring. (Photo by M. Hoefnagels)

Skyn (polyisoprene) condoms are impermeable to green food coloring. (Photo by M. Hoefnagels)

Naturalamb condoms are permeable to green food coloring. (Photo by M. Hoefnagels)

The other twist that Cotner added was the potential for the use of calipers as tools for measuring sensitivity. Specifically, calipers are a perfect tool for conducting two-point discrimination tests on bare skin and through a variety of materials, enabling students to stretch a condom over a hand and test whether condoms reduce sensitivity and by how much.

I couldn’t wait until that lab came up in my class this semester, which it finally did last week. I thought students would gallop to try those new tools, but alas, they did not. In our Tuesday section, they did the same old experiments–see how far the condoms can stretch, see how much fluid they can hold, or see how much weight they can bear. The end-of-class presentations were well done but somewhat redundant to each other. For Thursday lab, I thought it might help if we assigned a specific tool to each group. One group was assigned calipers as a tool, and another was assigned time. I hoped they would design the experiments as I would have, but alas, they did not. The team using calipers used them to figure out how far the condoms stretched widthwise; the team assigned to measure time didn’t end up doing that at all, despite the TA pointing out natural vs. latex condoms and explaining the significance of the green food coloring. Well, at least the presentations at the end of class had more variety, so that was a win, but I still didn’t see the creativity I had hoped for.

I thought a lot more about this after Thursday’s lab and it occurred to me that we may be asking too much from our students. We simply give them a list of materials and a limited amount of time, so it’s no wonder they ignore all the information available to them about condom construction and permeability and instead gravitate toward the simplest, quickest experiments. Next time I teach the class, I’m going to add two tables to the lab manual. One table will list all of the brands and styles of condoms available, along with the material they’re made of and whether they protect against STIs. The other table will list all of the other materials, what they’re for, and what sorts of questions they might be used to answer. I still want them to design their own experiments, and I think we will continue to assign at least one tool to each group so we keep getting a good variety of presentations. I’m hoping that with more information they can arrive at more interesting questions and better-designed experiments. Watch this space for updates; I’ll let you know what happens!

Natural Selection in Tortoises: A (Homemade) Video

[Doug Gaffin and Marielle Hoefnagels worked together to develop the materials used in this post.]

A while back, I wrote a post on an activity that connects genotype, phenotype, and natural selection. In a nutshell, the activity uses colored chips to represent alleles in cod. Students selectively “harvest” the largest fish over multiple generations and observe what happens to allele frequencies in the population.

What’s so funny about natural selection? (Galapagos tortoise photo by M. Hoefnagels)

This activity leaped to our minds when my husband and I were invited to give a lecture about natural selection to a group of non-biologists as we were all visiting the Galapagos Islands. We decided to adapt the cod activity to illustrate how natural selection could select for long necks in tortoises—we were particularly interested in driving home the point that tortoises didn’t “decide” or “try” to evolve in response to their environment. Our original intention was to have the group actually do the activity, but in practicing it before the lecture, we quickly realized that the activity involves quite a bit of counting and other tedious tasks that would use up our entire lecture time.

So we decided to do the activity in our hotel room, film it, and turn it into a video that we could show to our companions; you can see it here. The video, which is 2 minutes and 45 seconds long, requires a bit of explanation. It begins with a founding population of 10 tortoises, each of which inherits a total of six alleles for neck length. The alleles are represented by puzzle pieces of different colors: pink = 4 “length units,” yellow = 3 units, blue = 2 units, and purple = 1 unit. To assign genotypes to each tortoise in the founding population, equal numbers of alleles of each color are placed in a bag and shaken. Each tortoise receives a random assortment of six alleles. In the first 25 seconds of the video, we randomly select alleles from the bag to assemble the tortoise genotypes.

A tortoise from the “game board,” annotated to show the three genes and four possible alleles controlling neck length.

Next, the number of alleles of each color is tallied for each tortoise. The number of pink alleles is multiplied by 4, the number of yellow alleles is multiplied by 3, the number of blue alleles is multiplied by 2, and the number of purple alleles is multiplied by 1. These numbers are added to calculate the neck length of each tortoise. The five tortoises with the shortest necks do not survive (their totals are circled in the video), and the average neck length for the founding population is calculated. We are now through the first minute of the video.

For the next 27 seconds, the alleles for the shortest-necked tortoises are wiped off the board, the five survivors have their alleles doubled, and all of the alleles are swept into the bag and scrambled. At 1:27, we are ready to begin Generation 2. Each of 10 tortoises again gets a random assortment of six alleles, the numbers are tallied, the unfortunate ones with the shortest necks are identified for elimination, and the generation’s average neck length is calculated. We’re now about 2 minutes into the video. Then the survivors of Generation 2 have their alleles doubled and swept into the bag, and the start of Generation 3 is signaled at the 2:22 mark. By 2:45, the Generation 3 numbers are tallied.

The selection pressure against short necks in this simulation is very strong, so it’s not surprising that three generations is enough to produce a prominent trend toward long necks:

Whether using cod or tortoises, this activity is really good, and we are indebted to the inventors of the cod activity. If you want the tortoise version of the worksheet and student instructions, please leave a comment and we’ll send them your way. Or, if you simply want to show the video and explain it to students as you go along, feel free to do that as well.