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October 2020

Reading Astronomy News: Betelgeuse Might Be 25% Closer Than Previously Believed

By Stacy Palen

This week, I draw your attention to this piece of news that neatly encapsulates many of the concepts that you might be teaching at this point in the semester! Betelgeuse’s recent variability may be caused by dust and pulsation—so no nearby supernova in the works for us this year. That’s typical 2020 for you right there. Disappointing, all around.

Below are some questions to ask your students based on this article.

1) Why were astronomers, earlier in the year, talking about Betelgeuse exploding as a supernova sometime soon?

Answer: Because it had abruptly become dimmer, and evolution to supernova was one possible explanation.

2. What key conclusion in this most recent study definitively rules out the supernova-soon scenario?

Answer: Betelgeuse is still fusing helium in its core, which means that it has a significant amount of time left before it makes the full, onion-like set of fusion shells that precede a supernova.

3) Typically, astronomers first determine the distance to a star and then infer its size from knowing something about its evolutionary state and where it sits on the H-R Diagram. What did astronomers do differently in this study?

Answer: In this study, astronomers used stellar seismology to find the size of the star first and then worked backwards to determine the distance. This distance agrees (it is within the error bars) with previously determined distances to Betelgeuse.

4) Will Betelgeuse eventually explode as a supernova (even if we don’t get to see it this year)?

Answer: Yes, because it is a red supergiant.

5) Will that affect life on Earth?

Answer: Probably not. It is too far away to have an impact on life on Earth, although it would become incredibly bright for a short time.


Classroom Resources: Zombies and Aliens

By Stacy Palen

Apropos of the last few posts by Ana Larson about online classes and cheating (Thanks, Ana!), this week, I’m working on my Astro101 midterm.

It’s important to state up front that I think the purpose of exams varies from course to course. In Astro101, I think the purpose of exams is to make students look back over the last several weeks and connect different concepts across the material. For Astro101, the review is the goal, as far as I’m concerned. Therefore, I design my exams to guide them to do that review in a fun and engaging new context. In contrast, in a different course, such as Physics with Calculus, I have other goals, and they really need that material to be quickly accessible and at their fingertips for the next course. I design those exams differently, and I ask them to do the review on their own and then take the exam.

Historically, my Astro101 exams are story exams. I plunk students down on desert islands or in zombie apocalypses or some other contrived (and not entirely realistic) situation, and ask them to solve astronomy puzzles in order to survive. They might need to be able to tell time by the phase of the Moon, or find out whether it’s before or after the vernal equinox by judging the position of the rising Sun against the (formerly determined) position of Orion’s belt. I’m always bemused that students tell me that they think these exams are fun and practical.

I give students several days to do them, because they really do need to read the question and then think about it for a while—in this particular class, I’m not interested in whether they can do things quickly. And they can use any resources they have except other people.

But the things that I really like about these exams is that they are:

  1. Motivating: Students want to figure them out for themselves…because how could they ever know if they could survive the zombie apocalypse otherwise?!
  2. Fun: Students like to take them. Truly. They talk about them to their friends, and I usually get questions on the first day of class about whether I’m going to do this kind of exam again. Sometimes, even in other courses, if a student took Astro101 with me, they’ll ask if we are going to have fun exams or normal exams.”
  3. Fast to Grade: I have students draw pictures to answer a lot of the questions, which I can then grade out of a scale of three in less than a few seconds. For example, if the answer is first quarter, the Moon, Earth, and Sun are present and in the right orientation (3); they are all there, but drawn for third quarter (2); they are not all there or are in a completely different orientation, but they still drew something (1); or they did not answer the question at all (0). It typically takes me a full day (8-10 hours) to grade 120 exam papers because these picture questions take virtually no time to grade.
  4. Easy to Change, from One Semester to the Next: For example, I give them some data about the altitude of Polaris and ask whether they need to go north or south to reach a certain point. I can change that altitude, and people who are looking up answers online will not notice. So if I get last semester’s answer, I know to separate that exam to a different pile for…careful study. Or maybe they notice that this year it’s different. But to know why that difference matters, and give the correct answer, requires processing the material. And that meets my goal.
  5. Difficult to Cheat, Given My Goals: If I make them draw pictures in their own hand, then at some point, the information went through their brain, so some of it will stick. I’m satisfied because it meets my goal that they need to review the material and apply it in a new context. Because that’s my goal, I’m not bothered about how they go about it.

This semester, I hesitated all weekend about whether to send them the zombie apocalypse midterm. It seemed…insensitive, maybe…or just too stressfully close to reality. But then I made a joke of it, instead: It’s 2020of course there will be zombie apocalypse! I bet they LOL and dive right in.


Classroom Stories: How to Handle Cheating in Online Courses: Part 3

By Ana Larson

Ana Larson, co-author of the Learning Astronomy by Doing Astronomy workbook, gives us one last post about how to reduce cheating in online courses. 

To discourage academic cheating at the start of each quarter of my online courses at Seattle Central College, I started with an assignment where students had to complete a graded quiz (multiple takes permitted) on the content of the course syllabus and the policies and procedures of the college. Extra emphasis was given on the college's honor code and what, exactly, cheating included. My syllabus included explicit examples of what constitutes plagiarism and the consequences when unreferenced direct sources are used. In the last 5 years or so, students could use up to 3 outside sources, but those outside sources needed to be properly referenced using correct MLA or APA format. Students were given examples and helpful web links to show them how to do this.

Every quarter, there were at least 3-4 students in my course who lacked even the basic study skills. I envisioned them reaching a conceptually difficult concept, and rather than taking the time needed in a quiet, dedicated study area, immersing themselves in social media, texting, playing games, and cheating to find the answers. How are we supposed to teach study skills as well as astronomy? What if our departments require a definite amount of material that we are required to cover each term? Holy macaroni! We have families, other responsibilities, places we need to be, and people we must meet! It was frustrating to me that I spent a lot more time with some students and disproportionately less with the rest.

Unfortunately, over the 20-plus years I taught at the college, I did not keep records of the number of students who cheated, how they cheated, or whether (if any) a change in my policies or procedures made a difference. The course enrollment was limited to 30 students. Out of the number enrolled on the first day of class, usually 20-24 students completed the course. Those students included late registrations to replace students who dropped, complicating what would already be small-number statistics.

Fortunately, there are formal studies on academic cheating to which we can refer. I've mentioned the book Cheating Lessons: Learning from Academic Dishonesty by James M. Lang (Harvard University Press, 2013), which is an informative source covering various aspects of how students cheat and case studies of instructors who were able to reduce cheating and improve overall student performance. I recommend this book as he also brings in research from many instructors noted for their expertise and excellence in teaching.

The 4 features of a learning environment that may pressure students to resort to cheating are [1]: 

  1. An emphasis on performance
  2. High stakes riding on the outcome
  3. An extrinsic motivation for success
  4. A low expectation of success

With an emphasis on performance, students just need to demonstrate that they know the right answer at a certain time. A common example of high-stakes pressure is an exam or assessment that determines a major fraction of a student's grade. When an extrinsic motivation for success came from parents who placed a much higher priority on good grades than students, those students were more likely to cheat [2]. Most, if not all, of us have had students who believe that they cannot "do" math or science. They have not been successful in the past and thus carry a low expectation of success in astronomy. If students need a natural world or quantitative analysis course for their majors, they might just do everything possible to pass.

These considerations would seem to involve modifying our course content while simultaneously trying to survive the transfer of our in-person courses to online settings! During my two decades of teaching online courses, I had two main goals for making changes each quarter: 1) reduce cheating and improve learning through increased intrinsic student motivation, and 2) keep myself from becoming bored or complacent with the syllabus.

Let's start with increasing the intrinsic motivation for learning astronomy. Bring in a graded discussion forum for each lesson that has students comment on something current and related to the lesson. For example, news about potentially hazardous asteroids can cover telescopes, orbits, life on Earth, and so much more. How do we use Kepler's and Newton's laws to track these objects? I have also used the web-research topics given in Stacy's textbooks. If students can see the connection between astronomy and how it relates to what they already know or have read about, their personal motivation to learn should increase [3].

How might we move from grading a student's performance in a class versus assessing their mastery of the concepts? We don't keep what we want them to learn a secret. What are the learning goals for the lesson? For which learning goals will students need to have advance preparation for the assignment? How do we give them that preparation? We make sure that the assignment teaches to those learning objectives, whether they are broad or narrow in scope. Our quizzes and exams then bring in questions that directly assess their learning. At the start of each term, give students examples of how a learning goal leads to assessing their learning. I have had students request study guides for midterms and finals. My response: You already have that in the learning goals for each lesson. "You mean we need to study only that material?" (Well, yes, and the topics we've covered related to those goals.)

Consider lowering the weight of exams in order to reduce students' inherent stress in taking them. How often have we heard: "I don't test well”? Some instructors lower the stakes by giving multiple quizzes in order to drop one or more low scores. Another instructor might make a final exam optional or one that would only count if it increased a student's grade. This works if students have had a number of assignments over each term. In my online course, students had multiple assignments each week: a discussion post, a web-research assignment, a pre-activity quiz, an activity (from Learning Astronomy by Doing Astronomy), and a post-activity quiz. The discussions and web-research assignments were easy to grade because the guidelines given were clearly stated. The quizzes were multiple-choice, leaving the weekly activity for "line-item" grading. Since each lesson was structured the same, students (especially those new to online learning) gained practice in transferring learned skills to the increasing complexity of topics in a typical astronomy textbook.

From the research, Lang summarized: "The more times we test students in their recall of our course material, the more we are helping them learn it." [4] (The Lowering Stakes chapter pushes against a lot of preconceptions we might have on how students learn.)

Lang brings in research that states we should use formative assessment during our teaching. This involves brief, low-stakes activities that students do so that they and their instructors get feedback about levels of understanding. For in-class courses, these involve think-pair-share activities, minute papers, and clicker questions [5]. For online courses, these could be incorporated by using student groups or a dedicated discussion forum. The Learning Astronomy by Doing Astronomy workbook has associated pre- and post-activity quizzes for each activity. My solution, in addition to the multiple assignments and structured lessons, was to spend a lot more time in emails with these students and in answering specific questions they had about parts of an activity before they submitted it. There were cases where deadlines were extended and students resubmitted assignments. This was possible because the classes had less than 30 students. I have no answers for those online classes that have more than 50 students and welcome all suggestions and stories!

[1] Lang, James. Cheating Lessons: Learning from Academic Dishonesty. Harvard University Press, 2013. Print, p. 35

[2] Ibid., p. 46

[3] Ibid., p. 63

[4] Ibid., p. 114

[5] Ibid., p. 131