So many learning resources … so little time

Contributed by Matt Taylor

Suppose you are searching for that great new activity, assignment, or video for your class. Do you ever feel overwhelmed by the never-ending list of resources that you can find? Your students might feel the same way about the abundance of learning resources available to them. The good news is that we can help students take control in the chaos.

Many teachers and educational developers want students to have a variety of resources to help them master concepts. Since student learning styles or preferences vary, it is useful to provide different tools for a diverse body of learners.

But more is not necessarily better if students don’t know how to use the resources available to them. To overcome this gap in understanding, teachers could tell their students how each learning resource might be useful. Or better yet, teachers could encourage students to develop their own strategies. It turns out that the latter—asking students to make deliberate study plans—has a small but significant impact on class performance, according to Patricia Chen and her coauthors in a 2017 Psychological Science article. The research team set up an experimental group of students who developed specific strategies to use learning resources and compared the performance and psychology of those students to others who made no deliberate study plans.

Students who made deliberate study plans improved their course grade by about 4%.

Chen and the other researchers conducted their experiment in two introductory statistics classes. All students in these classes received weekly reminders of what resources were available to them. Also, in return for extra credit points, students were given the option to take surveys before and after two midterm exams. Participation in all four surveys was around 60%. Upon starting the first survey, students were randomly assigned to the control group or the experimental group (the class instructor was blind to this assignment). Post hoc analysis of these groups revealed that their members were not significantly different in terms of past performance, motivation, or confidence.

Pre-survey: Students in both the experimental and control group were asked questions targeting four areas: what grade they wanted to receive on the exam, how motivated they were to receive that grade, how important it was to receive that grade, and how confident they were in success.

Then, only the students in the experimental group went on to answer questions about their study plans. The first question asked them to select which resources from a list would be likely to help them study for the exam. For example, in an introductory biology course using a McGraw-Hill book, the list might look like this:

• Textbook readings
• Connect questions
• LearnSmart questions
• Smartbook learning resources
• Tutorial animations
• Office hours
• Lecture notes
• Previous exams
• Lab materials

After making their selections, students described in essay format how each chosen learning resource would help them. Then, they were asked to describe in detail when, where, and how they would use each resource to study in the week before the exam (e.g., “on Monday morning I will go to the library to rewrite my lecture notes”).

Post-survey: All students received the same post-survey. It asked questions about what resources students had used and how useful they thought each resource was to their learning. They were also asked about how much control they thought they had over their own grades, how much they plan for an exam, and how well they follow through with their plans.

Results: Students in the experimental group who participated in at least one pre-survey scored approximately 4% higher than their classmates who did not make deliberate study plans. Students who made study plans before both tests got an even higher boost in overall course performance. (Importantly, the treatment effect remains statistically significant even when the researchers removed the extra credit points that students received for participating in the surveys.)

Finally, the researchers also found that students who participated in strategic study planning on a previous exam felt more confident, less anxious, and more in control of their grades on an upcoming exam.

The research article has many other details that I did not explain here, and I encourage you to read it for yourself. But the major takeaway is this:

If you encourage strategic planning of learning resource use, then your students will be more confident and successful.

Do you encourage students to plan and self-reflect on their learning? How does it work in your classroom?

Reference:

Patricia Chen, Omar Chavez, Desmond C. Ong, and Brenda Gunderson. 2017. Strategic Resource Use for Learning: A Self-Administered Intervention That Guides Self-Reflection on Effective Resource Use Enhances Academic Performance. Psychological Science, Vol 28, Issue 6, pp. 774 – 785. https://doi.org/10.1177/0956797617696456

Antibiotic resistance in the lab … with actual bacteria!

Apparently my post on the antibiotic resistance activity using green, yellow, and red beads was a big hit with instructors, because lots of people want a copy of the worksheet. I have been happy to oblige, and now I want to follow up by calling your attention to a potential companion activity in the March 2018 edition of The American Biology Teacher.

I hasten to add the disclaimer that I have not tried this lab in my own class; I only just read about it this week. But the title certainly seems promising: Modeling the Emergence of Antibiotic Resistance in Bacterial Populations.

The authors outline a 5-day procedure in which students expose a bacterial population to antibiotics at two different times. On day 1, students select a single colony of bacteria from an agar plate and suspend the cells in a nutrient broth. The bacteria-laden broth is then swabbed across the surface of an agar plate. Students then place paper disks with and without antibiotics on the plate. The bacteria on the plate are allowed to grow overnight in an incubator and are then placed in the refrigerator until day 5. Meanwhile, the original broth also incubates overnight. On day 2, the instructor transfers bacteria from the broth into fresh broth and again allows the cells to multiply overnight in the incubator. On day 3, each student group swabs the resulting inoculum onto a fresh agar plate and adds disks with and without antibiotics. Like the plate from day 1, this plate is allowed to incubate overnight and is subsequently stored in the fridge until day 5.

On day 5, it’s time to collect the data. Students examine their plates, measuring the zone of inhibition around each antibiotic-infused paper disk. They use the data they collect to test two models of antibiotic resistance. According to the article, “Model 1 illustrates need-based acquisition of antibiotic resistance. Here, the bacteria rapidly gain antibiotic resistance only when exposed to the antibiotic.” If model 1 is correct, then the number of resistant colonies arising from the “day 1” swab should be equal to the number of resistant colonies arising from the “day 3” swab. In contrast, “Model 2 illustrates acquisition of antibiotic resistance through mutation. Here, the bacteria acquire mutations over time that increase their level of resistance to the antibiotic independent of antibiotic exposure.” If model 2 is correct, then the bacteria plated on day 3 should have more mutations — and more resistance — than those plated on day 1.

The article contains great illustrations, explores the molecular mechanisms of antibiotic resistance, introduces the idea of intermediate resistance, and has lots more information about how to implement this activity. The authors also offer student handouts and even a PowerPoint presentation. I can’t endorse it because I haven’t tried it, but heck, if you’re looking for antibiotic resistance activities that actually involve growing bacteria, you might want to check it out.

Reference:

Michelle A. Williams, Patricia J. Friedrichsen, Troy D. Sadler, Pamela J. B. Brown. Modeling the Emergence of Antibiotic Resistance in Bacterial Populations. The American Biology Teacher, Vol. 80 No. 3, March 2018; (pp. 214-220) DOI: 10.1525/abt.2018.80.3.214

Attend the best conference for people who teach biology labs … for free!

This is a good time to direct your attention to my favorite professional organization: The Association for Biology Laboratory Education, or ABLE.

I raved about ABLE in a previous post, and I won’t repeat my praise here. I just wanted to let you know that the 2018 conference will be at The Ohio State University from June 19-22. Registration isn’t open yet, so I can’t tell you the cost … but it’s typically in the $300 range and includes quite a few meals.

Are you thinking to yourself, “I can’t afford that!”? If so, I have good news for you. ABLE grants a limited number of registration waivers for graduate students, post-doctoral fellows, new academic faculty/staff, and faculty/staff from community colleges. You don’t even need to be an ABLE member to apply. (If you feel inspired to join, it is a real bargain at $15 for students/post-docs and $35 for everyone else.)

Now you are probably thinking to yourself, “That sounds great!” If you are, then hightail it over to the registration waivers website and apply by March 5. The application is simple. It collects basic information, asks you to describe “how attendance at this conference would be of benefit to you personally and/or your institution as a whole,” and then requires you to upload a CV and a letter of support from your chair. It’s that easy!

If you are awarded a grant, you can enjoy a meeting full of hands-on activities and wonderful, collegial colleagues on ABLE’s dime. (Note that travel and lodging expenses are not included.) I urge you to give it a try; you won’t regret it.

Antibiotic-Resistant Bacteria: A Simple, Realistic Lab Activity

Every now and then I write a blog post about lab activities that worked in my nonmajors biology class. For example, I have written about reptilobirds (an activity combining meiosis and inheritance), staining banana cells to illustrate digestion in plants, and building models of protein synthesis with candy.

Here’s another topic that nonmajors (and everyone else) ought to know about: the development of antibiotic resistance in bacteria. If you teach biology, you might have learned about antibiotic resistance so long ago that you assume everyone else knows about it too. However, I learned this semester that the misuse of antibiotics is still a real problem. During the week before our “Bacteria and Disease” lab, one of my students came into my office with clogged sinuses. He looked miserable and said that he’d been sick for weeks. He then reported that he had taken some of his roommate’s leftover antibiotics, and although he felt better for a while, he soon got worse again. You did what?! Of course you got sick again! How could you not know that was a bad idea?! I scolded him (more gently than that) and mentally reminded myself that education really does matter.

Staphylococcus aureus. Source: Wikimedia commons

Of course, our lab manual already has an activity that addresses antibiotic resistance. I tried it once or twice. Students used different types of colored pencils (representing various strains of bacteria) to fill in a diagram of lungs in the lab manual. When they tried to erase the pencil marks (i.e., used antibiotics to kill the bacteria), they discovered that not all of the marks would disappear. They were supposed to conclude that antibiotics don’t kill all types of bacteria. The activity was so dull, predictable, and ineffective that I soon abandoned it. For many semesters we’ve showed a video about antibiotic-resistant tuberculosis bacteria instead.

But then I read this article by Eva M. Ogens and Richard Langheim in The American Biology Teacher and I decided to give one of the activities a try. It was appealing because it connects antibiotic resistance directly with something that nearly all students have done: taken a prescription of antibiotics. The simulation uses dice and inexpensive pony beads to model the evolution of bacteria over a course of antibiotics. The pony beads are in three colors to simulate three degrees of resistance to the drugs (we used green for least resistant, yellow for resistant, and red for most resistant).

After a brief introduction, each pair of students is given a petri dish containing a “bank” of 20 green, 15 yellow, and 15 red pony beads. Each student transfers 13 green beads, 6 yellow beads, and 1 red bead to a separate dish, which represents the body and the bacteria currently infecting it. Students are told they are taking antibiotics to fight the infection. They are then instructed to roll the die and record the number in a table. Rolling a 1, 3, 5, or 6 means they remembered to take the antibiotics and get to remove 5 bacteria from the body. Least resistant bacteria die most easily, so green ones are removed first. Once there are no more green ones, yellow ones can be removed. Red ones die last. Rolling a 2 or 4 means they forgot to take their drugs.

The die, “body” (dish with four surviving red beads), bead bank (dish with many beads), and data sheet. Photo by M. Hoefnagels.

Critically, the next step is reproduction: Students add one more of each color bead that has survived in the “body.” This was the only stage at which students tended to make mistakes. Some pairs forgot to do the reproduction part entirely; others put green beads back in the body even after all the least resistant bacteria were supposed to be dead. Both errors change the outcome of the activity, so clear instructions are essential.

Students then repeat the roll/removal/reproduction steps. At each round, they record the number of bacteria remaining until no bacteria remain in the dish. Afterwards, they answer questions on the worksheet. Most of the questions are fairly straightforward, but we were surprised at how many students had a hard time articulating the relationship between bead colors (representing genetic diversity) and the events of natural selection (less “fit” bacteria were eliminated first, leaving the best-adapted to pass their resistance alleles to the next generation).

One of the strengths of this activity is that the bacteria fall into a spectrum of resistance. I’ve observed that even thoughtful students have trouble understanding why antibiotic-resistant bacteria would ever die in the presence of antibiotics. The somewhat-resistant yellow beads and the more-resistant red beads remind students that most bacteria are vulnerable to antibiotics, but some are more resistant than others. Natural selection acts on this genetic diversity.

Note that this simulation lends itself well to graphing activities. One simple idea would be to have students graph the number of bacteria of each color over time. Another would be to collect the data from the entire class and have students graph the relationship between the number of times the antibiotics were forgotten and the number of rounds of antibiotics required to kill all the bacteria.

The writeup in The American Biology Teacher is very good, with one exception: It is difficult to discern from the narrative that 5 bacteria should be removed at each round. We developed a handout that clarifies the instructions and includes a detailed table for recording data. If you want a copy, please leave a note in the comments section and I’ll email it to you.

Reference:

Spreading Disease – It’s Contagious! Using a Model & Simulations to Understand How Antibiotics Work. Eva M. Ogens, Richard Langheim. The American Biology Teacher, Vol. 78 No. 7, September 2016; (pp. 568-574) DOI: 10.1525/abt.2016.78.7.568

Selling the laptop ban: An activity

In my last blog post, I reported introducing a new no-laptop policy in my nonmajors biology class. We just finished week 3, and things are going well — there has been no pushback, and I really enjoy looking out at a sea of faces instead of the lids of their laptop computers.

Image source: Wikimedia

One of the studies that influenced my to-ban-or-not-to-ban deliberations over the summer was a study describing three experiments by Mueller and Oppenheimer. In a previous blog post, I went over the study in some detail; I’ll pull out a quote here from that post:

In the first experiment, students watched TED talks and took notes either longhand or on laptops that were disconnected from the Internet. Half an hour later, the students answered factual recall and conceptual application questions about the talks. Although the two groups did not differ on the factual recall questions, students who took longhand notes did better on the conceptual application questions. The researchers also found that students who used laptops wrote more words than those who took longhand notes, and that the laptop users had much more “verbatim overlap” with the lecture content. What the authors called “mindless transcription” predicted lower performance on the post-lecture questions.

To help my students understand why I adopted this policy, I used my “process of science” class during week 1 to explore this first experiment. After introducing the elements of an experiment, I distributed the abstract for the Mueller and Oppenheimer article:

Taking notes on laptops rather than in longhand is increasingly common. Many researchers have suggested that laptop note taking is less effective than longhand note taking for learning. Prior studies have primarily focused on students’ capacity for multitasking and distraction when using laptops. The present research suggests that even when laptops are used solely to take notes, they may still be impairing learning because their use results in shallower processing. In three studies, we found that students who took notes on laptops performed worse on conceptual questions than students who took notes longhand. We show that whereas taking more notes can be beneficial, laptop note takers’ tendency to transcribe lectures verbatim rather than processing information and reframing it in their own words is detrimental to learning.

I asked the students to work in groups to write a testable hypothesis in IF

… AND [test] … THEN [prediction] format, using information from the abstract. This turned out to be a challenge; about half of the groups resisted proposing an “IF” explanation. That is, I was hoping for something like this: “IF taking notes on a laptop promotes shallower processing, …” A typical response, however, was “IF taking notes longhand rather than with a laptop is better, …”

After some discussion, however, we settled on a suitable hypothesis. I then gave them 10 minutes to propose an experimental design to test the hypothesis, including independent variable, dependent variable(s), and standardized variables. This went more quickly than expected, and when they shared their designs it was clear that most groups did not find it difficult.

Next, I revealed the design of the first experiment in the Mueller and Oppenheimer study. In a nutshell, 67 students watched a TED talk and were told to take notes either with a laptop or with pen and paper. Afterwards, all subjects did 30 minutes of memory tasks unrelated to the TED talk. Everyone then took a test containing factual and conceptual questions about the TED talk.  Using this information, I asked each group to draw a graph of the predicted results on the board. Most groups had no difficulty deciding on a bar graph or determining which variable should go on which axis. Interestingly, however, only one or two groups differentiated between the two dependent variables (performance on factual questions and performance on conceptual questions); most just used “test score” on the Y axis.

I then showed figure 1 from the paper, so students could compare their graphs to the corresponding graph from the actual study. Students seemed pleased to see that their graph-drawing instincts were correct.

Well, we were about out of time! I briefly showed the remaining two figures in the paper, which support the last sentence of the abstract. Figure 2 shows that laptop users can take down significantly more words than longhand note-takers, and figure 3 shows that the notes of students using the laptop had significantly more verbatim overlap than did longhand notes. If I had more time, I would have had the groups draw their own conclusions from the two figures—instead, I just told them why the figures were important.

Overall, I liked this activity because it allowed students to think critically about how to design a good experiment about laptop use, predict results that would be convincing, and see the results from the primary source. Although I can’t be sure, this activity may have helped to prevent pushback from students since I showed them instead of just told them why I was enforcing the laptop ban—and hopefully they understand it is for their own good! Next semester, I hope to manage time better to allow for a wrap-up discussion about the study: What did they think? Is the study “perfect”? Is its argument convincing?

If you’re considering a ban of your own and would like the PowerPoint slides I developed, please leave a comment and I’ll send them your way in a jiffy.

A laptop ban at last

More than three years ago, I wrote a blog post about the debate over allowing cell phones and laptops in class. In the blog post, I summarized a study by Mueller and Oppenheimer showing that students who took notes on a laptop did not do as well on conceptual test questions as those who had taken notes by hand.

I thought about this issue a lot more over this past summer, and about a week before this semester started I decided to take the plunge: No more laptops and cell phones in my nonmajors biology class. Here are some of the factors that influenced me:

This is the “Family Feud” style slide I used to explain why students shouldn’t use laptops in class (besides distractions to themselves).

• I rediscovered the Mueller and Oppenheimer study, which suggests that the very slowness of taking notes by hand actually enhances learning.
• I observed a few instructors teaching over the spring and summer semesters. From my vantage point at the back of the classroom, I saw that much of what happens on laptops has nothing to do with the class.
• I recognized that goofing off on a laptop (or cell phone, to a lesser extent) is not just a private act; it distracts and influences neighboring students.
• I talked to a student who took my class in a previous semester. She said that she prefers note-taking by hand because she can sketch diagrams as she goes.
• When students have their noses buried in their own personal electronic devices, they are not interacting with their classmates. I want my students to get used to talking to each other.

I used the slide accompanying this blog post to introduce these arguments to my students. Before I revealed my Family Feud “survey says” answers, I asked how they would answer the question posed in yellow. They came up with two more arguments that I hadn’t thought of: (1) It’s disrespectful to the teacher; I think a tiny tear of gratitude came to my eye when I heard that answer. (2) Laptops can be used to cheat, e.g., students can look up answers to clicker questions instead of thinking about the material themselves. I’ll add one or both of those to the Family Feud slide next time I teach.

The only thing that makes me uncomfortable about imposing a laptop ban is that students are supposed to be learning to take responsibility for their actions. My class is mostly populated by freshmen and sophomores, and I’d like them to feel as if they are in a college class, not in “13th grade.” But I decided to experiment with a ban because I think the pros listed above outweigh this con.

And how have the students responded? Surprisingly well! I was prepared to give individual students permission to use their laptops under certain conditions, but none has asked. It’s only week 2, but things look good so far.

What about you? Have you ever banned laptop use in your class? How has it worked? If you are against banning laptops in the classroom, I’d be curious to hear your thoughts as well.

Next time, I’ll show you how I used the Mueller and Oppenheimer study in a classroom activity to win my students over. Stay tuned!

Looking for a scantron replacement? Consider ZipGrade.

As I’m preparing for the upcoming semester, I have been trying to find ways to save money in my class. One obvious cost-cutting target is scantron forms. Yes, I suppose I could make my students buy them, but I have never felt right about that—it just adds insult to injury to make students buy something they must have for an exam.

Well, I just learned about one scantron replacement. It’s called ZipGrade. It lets you use your cell phone’s or tablet’s camera to scan in paper test forms (available free at the site). I just downloaded it and gave it a whirl, using my ancient iPad2 and two sample exams with two different keys. I have to say, I am impressed!

The basic idea is that you hover your phone’s or tablet’s camera over each student’s paper until marks on the four corners of the page align with a template that appears on screen. That’s the only part that took me a while to master, and it’s the only downside I can see for this app: Scanning student pages one by one is nowhere near as easy as feeding a stack of scantron forms into a machine. Keep this in mind if your class is large. Anyway, once the scan is complete, you can see the score on the screen right away, and if you want, the app can show you a picture of which questions the student got right and wrong. It saves the data immediately, and you can go on to scan the next one.

ZipGrade offers an amazing array of features. You can find a complete list here, but the most important ones for my purposes are these:

• You can download free PDF test forms that you can print out and copy yourself.
• Test forms have 20, 50, or 100 answer bubbles, but you don’t have to use them all. The only one with a 9-digit slot for the student ID is the 100-answer sheet, so that’s the one I’ll use for all of my exams.
• You can create up to 5 unique answer keys per test.
• The app does the item analysis for you.
• You can assign a different point value to each question, including fractions of a point.
• You can export the complete data set, including individual student responses, as a .CSV file.

Here’s a tutorial that shows you how it works. I’m not sure how long ago the video was created, but be warned that the pricing information is not exactly consistent with what’s on the ZipGrade website. That is, according to the website, you can download ZipGrade free and scan up to 100 papers per calendar month. If you need to scan more, you can pay $6.99 for a year. Other than that, the free and paid versions are identical. What a deal!

I know that ZipGrade has competitors, but I haven’t looked into them. And I suppose I should also say that I have no affiliation with ZipGrade and no stake in their success. I just found the app and thought I’d share it. If you have experience with ZipGrade or other scantron replacement tools, please share your thoughts by writing a comment.

Trail cam images and data for your lab

Earlier this month, I went to my favorite conference of the year: the one for the Association for Biology Laboratory Education. If you don’t know about it, check it out. Each conference follows a workshop format, so you don’t sit and listen to people drone on about what they do. You actually get to try the lab activities yourself and see if they’ll work for your own class.

Welcome to WildCam Gorongosa!

At one of the workshops I attended at this year’s conference, I learned about a great resource from HHMI BioInteractive. (Loyal readers of this site may recall that I previously wrote about their wonderful rock pocket mouse evolution video.) The focus of the workshop was the resources posted at HHMI BioInteractive: Gorongosa National Park. This park, in Mozambique, was all but destroyed in that country’s civil war, but it is now rebuilding.

Before we came to the workshop, we watched a video called The Guide; it was a good introduction to the park’s history and to a young Mozambican who wants to be a guide there. After a brief discussion in the workshop, we launched WildCam Gorongosa, “an online citizen science platform.” We launched the WildCam and clicked “Get Started!” After a brief set of instructions, we started counting and identifying the animals photographed in camera traps. The site shows you one photo at a time, and you click the names of any animals you see, how many you see, and what they are doing in the photos. Of course, few people are experts on Africa’s wildlife, so you might not know your duiker from your eland. Not to worry, they provide a guide to the common animals, and they encourage you to take your best shot even if you don’t know what you are looking at. Lots of people look at each photo, and experts weigh in on those for which citizen scientists cannot agree. So there’s no real risk of messing up someone’s Important Science.

Sample trail cam image. See the baboons?

As we clicked through the pictures, we were encouraged to start thinking about questions we might ask about wildlife at Gorongosa. Each photo includes a button that shows information about the image: the camera’s identifier, the date the image was snapped, the season, the time (day/night), the distance to the nearest human settlement, the distance from water, and the biome where the camera is located. (Other resources on the site include an interactive map in which you can see the camera locations, the park’s major landscape features, the nearby villages, and so on.) It doesn’t take long before you start wondering: Do baboons always hang around in groups? How can duikers and oribi coexist when they seem to have such similar niches?

After refining our questions and framing hypotheses that we could actually test using the trail cam data, we were ready to get some answers. The data from more than 40,000 images are compiled in a database that you can access by going to the WildCam Lab. Click “Explorer.” You’ll get a brief introduction to the site, then you can download all the data or filter the dataset by species, habitat, season, time of day, date, distance to humans, and/or distance to water. Once you figure out what you want, you can download the data as an Excel spreadsheet and analyze them to your heart’s content.

The interface for filtering the data before download.

This blog post is highlighting just a part of the actual activity, which is spelled out in detail at the HHMI site — complete with educator materials, a student worksheet, and even a tutorial that shows students how to use pivot tables in Excel. And that activity only scratches the surface of what’s available at HHMI’s Gorongosa site. I haven’t looked at most of these materials myself yet, but just browsing through the resources, I see an animation of Gorongosa’s water cycle, a food web activity, a biodiversity activity, a human impacts activity, a biomes activity, an ecological pyramid activity, a lion-tracking activity, and so on. It’s really amazing.

I am planning to use the WildCam material in my nonmajors biology lab this fall, as a replacement for our rather silly animal behavior lab (sorry, isopods!). The activities at the Gorongosa site should get students to think about real data and engage in meaningful science, which are goals of all my nonmajors biology labs. They should also allow students to analyze animals (and plants) in their native habitats, doing what they do when no one is looking. For my students, it will be a window into the forests and savannas of southeast Africa from the comfort of our second-floor biology lab.

Wish me luck! In the meantime, big thanks are due to ABLE for sponsoring the workshop and to HHMI for making such high-quality materials.

Radiometric Dating: Need to Practice?

Last year, we posted a video explaining how to do three types of radiometric dating problems; we wrote about it in this blog post.

I am pleased to report that the prodigious Matt Taylor has now released an activity with four sample problems that your students can work. The first two problems are pretty typical. In question #1, students are given the half-life and % of the isotope remaining and must figure out the age of the fossil. In question #2, students are given the age and half-life, and they must determine what % of the isotope remains.

The last two questions are different. In #3, students are given the graph of isotope decay and told the half-life of the isotope; they must click on the part of the graph corresponding to a particular time. And in #4, students are given information about the % remaining of three isotopes and must arrange them in order based on their half-lives.

The video is designed to walk students through this content, step by step, and the activity can help students assess their understanding. We encourage you to share both resources with your students — or better yet, go through them together, pay attention when your students struggle, and use your insights to refine your teaching. (Yes, I’m looking right at you, teacher with a growth mindset!)

One Good Clicker Tip

The end of the semester is not a great time to introduce a tip for using clickers; I am sure this post would have been more useful in January! But I can’t control when ideas for blog posts drop into my email, and I received a good one recently.

It’s an article called Clicking Your Way to Flipping Your Class, and it appears in Tomorrow’s Professor—an excellent resource for professors in any discipline. The Tomorrow’s Professor article that recently landed in my inbox is a reprint of an article that originally appeared in the February 2017 issue of the newsletter of the Federation of European Biochemical Societies (http://www.febs.org).

iclicker2, ready for action. (Photo by M. Hoefnagels)

I’m not a big classroom flipper myself, but I am madly in love with clickers. What I like about the “Clicking Your Way…” article is its subject, clicker-based peer instruction. While I don’t follow the author’s methods to the letter, the article reminded me of one of the ways I use clickers in my class. (You can read about another way that I like to use clickers here: “Pointless” clicker questions.)

I use the iClicker2 and enjoy watching the LCD display at my computer as the students’ answers roll in. The display shows how many students have selected each answer choice in real time. If the question is easy or if the students have mastered the material, then I don’t spend a lot of time giving feedback on the question. Here’s an example like that:

What is the charge on an electron? (a) Neutral; (b) Negative; (c) Positive; (d) Depends on the element; (e) Depends on the isotope.

This question comes in the context of a series of questions designed to help students through the difficult concept of polar covalent bonds. Nearly everyone (98%) in my last class got this question right. I could replace it with a more challenging one, or I could keep it in and consider that point to be a cheap-and-easy, morale-boosting reward for participation. So far, I have opted for the latter.

For a more difficult question, the display often reveals that the class is split between two (or rarely, three) choices. Those are my favorite questions because they offer an opportunity for students to learn by teaching each other. Here’s an example of such a question; it requires students to enter a number into their clickers (yet another reason to love iClicker2), but it could easily be converted to a multiple choice question:

How many of the following processes actually exist AND produce two cells that are virtually identical to the original cell?

• Meiosis in bacteria
• Meiosis in animals
• Meiosis in plants
• Mitosis in bacteria
• Mitosis in animals
• Mitosis in plants
• Binary fission in bacteria
• Binary fission in animals
• Binary fission in plants

The most popular answers are 3, 4, and 6 (the correct answer is 3). As the students enter their answers, I keep an eye on the display. I usually do one of two things if less than ~70% of the students are getting the question right. I may stop the polling (without showing the histogram) and say something like this: “Explain to your neighbor why you selected the answer you did.” After a minute or two of discussion, I poll the same question. Alternatively, I may choose the slightly quicker strategy of keeping the polling going while I tell the students something like “OK, most of you are choosing 3, 4, or 6. One of those is the correct answer. Pick one and explain your choice to your neighbor.” Either way, without any other intervention from me, student performance on the question typically improves.

I am always on the lookout for clicker questions that actually make students think. The blog post I linked in the previous sentence has one example of a good site for clicker resources, and here are some clicker questions from the University of Colorado Science Education Initiative.

Happy clicking!