Classroom Stories: It’s a Learning Experience!

By Stacy Palen

I remember when I was in school, things would occasionally go badly, or at least unexpectedly, and a teacher would often say “It’s a learning experience; it builds character!”

Well. Here we are in the midst of a global pandemic, building character all over the place!

My university is in finals week, and I’ve just finished grading my astronomy exams for both Astro101 and the Junior level cosmology class.

It’s a good time to reflect on a few things.

First, I started with the driving directive that I would “do no harm.” I took note of the scores for each student when we were all sent home and decided that this would be the lowest grade that the student could earn. I felt that this was only fair since an online class is not the same experience at all. If they had wanted an online class, they would have signed up for one!

As it turns out, about 75% of the students improved their score (some only slightly), while 15% of their scores dropped only slightly—not enough to matter in the final letter grade. That left me with a handful of students (10%) who reverted to their earlier score. These were clearly students who eventually stopped handing things in altogether; a couple of them let me know their very good reasons for doing so.

I think those results are interesting and would love to know if others had similar results in their classes!

Second, what an amazing opportunity this is to identify which things students can learn just by reading, and which things students need real live instruction in order to learn! Maybe I would call this “learning by conversation” to distinguish it from Learning by Doing. We were sent home right at the transition from the Solar System to stars, so all of stars, galaxies, and cosmology was carried out by asynchronous online instruction. I noticed the following in my Astro101 exams:

  1. My students basically understand the H-R diagram; they can add new stars to it and identify regions and stellar properties like temperature. However, they do not understand evolutionary tracks, and the misconception about stars evolving ALONG the main sequence remains, even though it is explicitly addressed in the text. I do not have this problem when I teach the topic “live.”
  2. Special and general relativity are full of misconceptions. It seems as though reading about it reinforces what they already think is true, even if what they are reading is actually saying the opposite of what they already think. They miss the subtleties and re-interpret the text to match what’s already in their heads from Star Trek or wherever. For these topics, they absolutely need to have someone see their foreheads crinkle in confusion and give them the chance to ask questions as they have them.
  3. Every misconception about the expanding universe is still there, even though the text tries hard to counter this. And the videos. And the simulations. This is fascinating. These misconceptions persist in part because we didn’t get to do the hands-on “balloon universe” activity (can your students find balloons in their house? I don’t have any). But partly, it’s because they don’t get to hear someone ask the question “but if everything’s going away, doesn’t that mean there has to be a center?” and get the answer 8 or 10 times in a class period.

I’m sure there will be more examples as I process, and think about how to learn what I can from this unplanned experiment. I’d love to hear what you are noticing about this idea of “learning by conversation.” It will help me think about tools to develop over the summer in case we are all teaching and learning online again in the Fall.

Current Events: Formal Education, The Fun They Had, and Plan B

By Adam Johnston

This week, we have a guest post from a colleague at Weber State University. In addition to teaching at Weber State, Adam Johnston is also the author of the blog First Drafts in which he writes about education, science, and personal experiences. In the post below, Adam discusses the shift in our methods of teaching brought about by COVID-19, stresses the importance of managing our personal expectations, and suggests using this moment to think about what our overarching educational goals should be. Click here to access the original post.


In the face of pandemic and social upheaval, what teachers and families and students are doing right now is nothing short of heroic. They’ve been sent away from their buildings and communities yet are told to still conduct school, and a steady stream of accolades are being appropriately shouted from our socially distant social media streams. Teachers I work with in the K-12 settings and my colleagues in university programs are building new vehicles and plans and schedules and methods on the fly, while they’re flying, and it’s all quite extraordinary. And our students — the two in my house are navigating all of this newness in the face of trauma as they try to finish a senior year of high school and a second year of college, respectively — are wading through completely new arrangements, unfamiliar structures, and major tectonic shifts. Daughter 1 still has belongings and a made bed in a dorm room hundreds of miles away that she essentially evacuated at the start of spring break; Daughter 2 is facing the reality of graduating from our K-12 system without a formal graduation ceremony with the people she’s essentially shared her entire lifetime with. These are just the two student stories right here before me, in our privileged home. There are literally millions of others, each with their own story.1

These are difficult times; I admire all that everyone, everywhere is doing.

And yet, I am quite certain that we’re going at it all wrong, for understandable reasons.

To be clear, I don’t think this education roller coaster was avoidable and I don’t have an immediate solution. School is in a massive mode of triage, and we’re doing the best we can in the moment with what we have in front of us. Let’s finish the year with that in mind, no judgements. And please, let’s not beat ourselves up when our teaching and our learning isn’t the same in these formats. In fact, let’s not even pretend that they could be.2

Schools are sacred spaces, places we’ve designed specifically to bring people together to learn, for their current selves and for our future citizenship and society. Sitting among the very greatest human inventions like poetry, science, democracy, beer, libraries, and music, I think that education should top the list. The problem is that we don’t realize that it is, in fact, invented — it didn’t come from out of the blue, after all, not handed to us on stone tablets — and that this means that we also have the ability to change it. At the same time, I think that schools are incredibly beautiful and beneficial and egalitarian and, overall, good, even as there’s always room for improvement and reform.

The latest model of education, a century old at least, is a vision of all children in America all walking up concrete steps and into congregating classrooms and spending roughly 180 days in these spaces among friends and caring teachers and chalkboards and frog dissections and readers and math manipulatives and recesses and maybe a unit on square dancing that doubles for both PE and music.3 Teachers love their students, and I don’t say this as a throw-away, trite line. I see this firsthand in classrooms. And, I know firsthand that students love their teachers. For all of the pains that we might associate with school and schooling, kids are walking up those steps into rooms where they are loved for who they are, where they collaborate and work with peers, and where they have a system that, for the most part, is designed to focus on the needs of each human. This may sound as if there should be rainbows and butterflies and fairy dust sprinkled about this fantasy scene, but I’ve worked with enough teachers, students, and classrooms that I can verify this is as true as my love for my own children.

In that genuinely caring context, schools and teachers create and cultivate community. There are reading circles and discussions; teachers know how to pair students together, and they know how to separate them; students share with teachers, in one way or another, that they’re excited or scared or having a tough go of things. I’m confident that every teacher worth their salt has a story of when a student, Kindergartener, 4th grader, high school senior, or pre-med major came to them crying. And I’m confident that each of those teachers knows about the celebrations in their students’ lives. And even when they don’t know the details they know when the kids walking through the door carry excess burdens or are lifted by extra joys in their lives. And in the mix of all this, teachers adapt to their students. Like I said, these are acts of love, hosted in brick buildings paid for with taxpayer dollars all over the country.


A couple years ago I reviewed the finalists for our university’s major teaching award. In the process, the other committee members and I pored over nominations and piles of supporting material, but the real joy of the task was in visiting these teachers’ natural classroom habitats.4 They were all expert in their fields and engaging in the classroom, well organized and clear. They were centered on students’ ideas and guided them not just through the details, but the big picture and purpose of a given teaching episode. I saw this in chemistry as well as in social work, in economics and education as well as in journalism. Yet, the teaching expertise and classroom seemed secondary to something else. The subtle but clear commonality in each of these extraordinary instructors was how they related to their students on a personal level. They revealed details about themselves and they knew their students, the personal stories, affects, efficacies, and histories. The connections and interactions were vibrant and joyful, simultaneously gluing and stimulating the class. In all this, it wasn’t merely a dissemination of information, but the building of relationships.

In contrast, I recently remembered and re-read Isaac Asmiov’s classic kid’s story, The Fun They Had. This was a futuristic vision when it was written in the 1950s, and still was when I read it as part of my reading packet around 1980. Set in the year 2157, the premise is that two kids are contrasting their version of a “teacher,” essentially a computer as envisioned before computers (or even microprocessors) were commonplace, with our human version. The children had to have their teachers tuned and occasionally repaired to deliver lessons in their own homes; and students turned in handwritten work that these machines evaluated. The plot twist here is that Tommy has found “a real book” in an attic and they talk about how ridiculous these pages are and how it comes from a time when schools were places children would gather and teachers were real people. As Margie considers the arithmetic lesson for the day at the close of the story:


She was thinking about the old schools they had when her grandfather’s grandfather was a little boy. All the kids from the whole neighborhood came, laughing and shouting in the schoolyard, sitting together in the schoolroom, going home together at the end of the day. They learned the same things so they could help one another on the homework and talk about it.

And the teachers were people . . .

The mechanical teacher was flashing on the screen: “When we add the fractions 1/2 and 1/4 —”

Margie was thinking about how the kids must have loved it in the old days. She was thinking about the fun they had.


I suspect there are students, now, thinking about the fun they had only weeks ago. And they have real people as teachers, on the other end of an internet connection that even Asimov hadn’t imagined two centuries of technology could create. These are the same loving teachers, dedicated instructors, who host students in the learning environments in our neighborhoods schools when the doors are open. And surely, I know, they do all they can to sustain these relationships in more meaningful ways than Margie and Tommy’s “teachers.” But I also know teachers who, daily, break down in tears because they cannot possibly connect with their students in the ways they can when they’re all sharing the same physical space.

Besides interpersonal connections, there are clear advantages to working with students face-to-face. These are interwoven with the way that we’ve deliberately crafted our school system. We have lab benches and sinks, performance spaces and whiteboards, recess spaces and reading circles. The simple act of walking down a hallway as a class is an act of collaboration; singing together in the music room is a community celebration. Walk by an old elementary school on a warm spring day and listen for the joy that seeps out of open windows.5 If all that there was to learn could be had by reading, then we’d simply teach the kids to read and then send them home with a collection of books. When you’ve finished those, come back and get more; and when you’ve finished all the books then we’ll give you a piece of paper that you can put on your wall and gain yourself admission to a new school with new books.

This is, at its face, absurd. We know that there’s more to learning than just reading books, or at least that the reading of the books or the listening to the lectures or the watching of the presentation doesn’t itself turn into learning. There’s a working with and among one another that creates new meaning. Application and practice create new levels of understanding. Gaining a sense of self and making connection to something greater are important, if not critical, pieces of what we aim for in our schooling. Students talk about this in their graduation speeches, that there’s greater meaning and application and synthesis, and that schools aren’t really about the delivery of information into students’ cognitive processors. We’ve all had the privilege of experiencing this in our schools, and our students talk about these learningful outcomes and how they result from being on a debate team, a basketball team, a historical debate, a physics lab. They talk about what they’ve learned through all of the connections they’ve built and interactions they’ve had, with teachers and students and others.

The community, relationships, direct interconnections with one another—these are all the things we can’t expect from online education, now or ever, simply because this isn’t what online education has to offer. Rather than wring our hands and lament this, we should celebrate it. Let’s look at all that our in-school education does for us and herald this as one of society’s great accomplishments; and then let’s not expect online to do the same.


But maybe we can do something fundamentally different with online education in the future. It can’t be the same as the schools we now have, but it could be something else, something additional, not a replacement but an altogether different system with an altogether different goal.

As an analogy, let’s take trains.

I love to ride the train, big or small, near or far, and in so many ways it’s the ideal form of transportation for me to get from my town to another that could be 30 minutes, an hour, or two hours away. I have to plan ahead and be conscious of the schedule and a few various regulations. The infrastructure for the train, right-of-way and tracks, employment of the operators, and all that background operation have to be engineered and arranged, but once it’s there I have an ideal way to get myself from point A to point B. The arrangement is so ingrained into a community that I could easily take it for granted.6

So I imagine the painful scenario that follows if, one day, trains are suddenly closed. After a brief pivot, everyone scrambles and looks for the alternative transportation mode, and while I am really upset about the lack of my smooth and fast transport, I have faith that I’ll be given an alternative, a “plan B.”7 I imagine being handed a backpack and some walking sticks, and perhaps someone checks to see if I have the right shoes on my feet and they offer an alternative pair of sneakers in case mine aren’t quite up to the task. Am I then setup to succeed?

I have all the tools of transit, albeit substitutions. But it should be obvious that I’m not going to walk the entire length of the tracks. And no one could expect me to go at the same pace as the train. With this new mode, I have limitations. I need to change my destination and expectations. And, I’d change my perspective and gaze.

This would be a completely new experience. I like walking. I love putting stuff into backpacks. I might even appreciate the new shoes to try. I won’t cover the same distance, and it won’t be as fast, but with each step I’m going to see different things than I would on the train. Everything goes by slower but the concentration on specific features would be more intense. I won’t get as far, but I’ll get somewhere. Details will be crisper, the pace will be my own, and there will be choices about how I make my way.

These walks won’t replace the train; they’ll make me appreciate it all the more. But they’ll also help me see what the alternatives will bring if, if, I’m so willing to use the new mode in a way that matches what it’s good for. At-home learning could be self-paced and introspective, the chance to break away from the regular commute. There are opportunities to take notice of what might be in my backyard or where the sun sets at night8; my writing could take on a different form, focus, and structure9; I’m going to make a lunch from scratch instead of brown-bagging it or waiting in the cafeteria line. These things are all small, but they still provide opportunities to know my world and build experiences in a different way.

All the while, I’ll miss school and appreciate that community, the collaboration, the love inherent in that space. I’m confident we’ll get the train running again — a faith I have simply because I can’t imagine our society or my own personal world without it. So, this introspective, self-contained time away from the formality and congregation of our school buildings might be a good chance for us to appreciate what traditional schools do for us as people, individually and collectively. We might have a better perspective on what we value and prioritize for schooling in the future — the things we can’t otherwise replicate.

For now, and for any other moment in the future when we don’t have our schools operating normally, let’s not try to replace the system. We can value alternatives for what they are, use them for what they are, even draw from them for additional resources and learning opportunities. But let’s not expect ourselves, even with fancy shoes, to walk at the pace or with the inherent community of a train. Let’s not expect new tools, unlearned and mostly untested and most certainly un-utilized until now, to attempt to be all that we really value about education. Let’s forgive ourselves. Let’s expect less of ourselves, our families, our teachers, and our students right now. Let’s appreciate the walk, and, next time, in the future, let’s think about how any “plan B” is not just a different tool, but something that has an altogether different purpose.

Much later, when there’s room to breathe, let’s think again about what we want from education in the first place, “the fun they had,” and if we’re using all our tools and modes in meaningful ways to reach those goals. But right now, in this moment, in these times and with these conditions, let’s breathe, give ourselves a break, share some compassion and empathy, and just get through the school year as best we can.




1 The other human member of our home, my wife, Karyn, teaches knitting classes. As I’m writing, she just walked by exclaiming how much more work she is putting into new formats for her students who are dialing in online. They’re appreciative, but replicating what she can do face-to-face is arduous, and actually impossible.

2 Watching the various classroom practices whirling around me as though I’m in an educational tornado, I asked a colleague if they’d let me into their now-online class, just to observe and understand various strategies. They were initially open, but then thought twice and said they weren’t happy enough about what they were doing to want anyone else to peek inside. I can’t blame them. 

3 The meaning of “all” and our dedication to it continues to have some inconsistencies. In spite of court rulings and legislation, schools are still segregated and unequal, and we can’t ignore this. I’m envisioning a shared ideal here, that we want all children to get a K-12 education and graduate. That traces back to the early 20th century, though the legacy of our schools goes back much further, still.

4 My favorite professional task is teaching, but my second favorite is observing others teach.

5 I know that “modern” schools are often sealed up and air conditioned, but I’ve been happy to get to live next to some older buildings with no such amenities.

6 Here in Ogden, Utah, while we don’t have the same rail infrastructure as people back East or in other countries, we do have a smooth commuter rail that extends up and down the Wasatch Front and connects to light rail systems in the Salt Lake metro area. More interesting, maybe, is the fact that Ogden is a traditional hub of railroad history, being the junction near the joining of the transcontinental line 150 years ago. This brought prosperity and interesting characters (and oh so many stories and legends) to Ogden, and we’re still built on that foundation even as the rail system has been supplanted by the interstate system.

7 A dear friend and backpacking companion tells me, “Plan B is the same as Plan A, but with rain gear.” This seems simultaneously so wise and dumb. And it feels universally familiar, in backpacking or otherwise.

8 It changes position every day, and as the seasons change the amount and direction it moves changes as well. Standing on an east-west running street as the sun goes down can give you some orientation, and watching this from the same place (though different times!) on different days will provide a good comparison.

9 Let’s admit that writing in the midst of a pandemic isn’t easy, though. There have been a lot of blank screens staring back at me these days. Giving myself the diversion to write in footnotes has been a good lubricant.

Current Events: Milky Way’s Warp Caused by Galactic Collision

By Stacy Palen

According to this article published by the European Space Agency, the extremely precise mapping being done by the Gaia satellite shows that the warp in the Milky Way Galaxy is moving far faster than expected. This implies that it is caused by interactions with another galaxy rather than by magnetic fields or the dark matter halo.

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

1) What is unprecedented about the data that Gaia is taking now?

Answer: Gaia is taking more precise position and velocity data on a very large number of objects.

2) What do astronomers mean when they talk about a “warp” in the disk of the Milky Way?

Answer: They mean that one side of the disk is twisted up, while the other side is twisted down.

3) Where else in your study of astronomy have you run into the term precession? How does that use of the term compare to the one used here?

Answer: Precession was also used to talk about how Earth’s pole points in different directions over a 26,000-year period. It’s similar to this usage because if you imagine an axis perpendicular to the warped disk, that axis would likewise point in different directions over time. The time scale here, however, is much longer.

4) What is it about the warp that makes it possible for astronomers to rule out all causes but one?

Answer: The speed of the warp matters. It moves too fast for anything but an intergalactic collision to be causing it.

5) Consider what you have learned about galaxy formation and interactions. If you were an astronomer, what might you look for in other spiral galaxies in order to confirm this result?

Answer: If warps are caused by interactions, then every time I see one, I should also see small companion galaxies that are very close—with orbits close enough to pass through the disk of the larger spiral galaxy.

6) The Sagittarius dwarf galaxy may be the cause of the Milky Way’s warped disk. What is the ultimate fate of the Sagittarius dwarf galaxy?

Answer: The Sagittarius dwarf galaxy will ultimately be absorbed by the Milky Way.

7) Speculate: after the Sagittarius dwarf galaxy meets its ultimate fate, what do you expect to happen to the warp in the Milky Way’s disk?

Answer: The warp should slowly disappear, once there is no longer a galaxy tugging the disk around.

Classroom Stories: Electron Transitions in the Atom

By Stacy Palen

Before we all were sent home because of COVID-19, my class completed a short in-class activity that was intended to prepare them for the study of stellar spectra. This activity can also be done by students taking online courses, although the big advantage of doing them in class is that it gives such insight into where students are struggling with the material!

This activity is all about transitions in the atom. I thought it was interesting that many of my students did not know about energy level diagrams (which I didn’t really expect), but I was surprised to learn that a fair percentage of them had never even heard of the Bohr model of the atom.

After listening for a while to the discussion, I was reminded that a fair number of my students are concurrent enrollment; they are actually high school students who are taking this course to fulfill their science credit. We can argue about whether that’s a good idea (I do not think that astronomy is a good substitute for chemistry).

The fact remains that they are taking my course and I need to teach them about a subject that is completely foreign to them.

This activity introduces the concept of electron energy levels, emission, and absorption. I struggled a bit here to introduce the idea that in order to make an upward transition, the electron has to get energy from somewhere, and therefore the “rest of space” will have less energy in it. I didn’t want to introduce Kirchoff’s laws yet, and they hadn’t yet seen an absorption spectrum. But they got the point, despite my unhappiness with the imprecise language I used.

Click here to access the activity for yourself and let me know how it works for you!

COVID-19 and Elementary Astronomy

By Stacy Palen

Well, this isn’t going the way we planned! Goodness!

As you may recall, I was already teaching in a substandard environment for the semester and now everything has moved online. Raise your hand if you were ready for that to happen! Yeah, me neither!

We were about four weeks away from the end of the semester when the University shut down face-to-face classes. That’s so very sad because I was almost ready to talk about black holes. Now all of cosmology will be done online without me getting to see their shocked faces.

I’m finding that the shift for “Astronomy 101” has not been so bad. It turns out I’ve been preparing for this for over a decade.

All of their work (except for exams) is coming in via Smartwork. I’ve beefed up those assignments a bit to include more work with the simulations and the videos that come with the textbook. This is easy to do in Smartwork by using the “Add Questions” tool, then using the Series filter to identify Video (VID) and Explorations (EX) questions, the latter of which make frequent use of animations and simulations.

I’ve opted to do everything asynchronously in order to accommodate our students, many of whom are non-traditional. Most of them have other stressors, like home-schooling their children, losing their jobs, caregiving, or even just having to share their computer with everyone else in their household.

It turns out a significant fraction of them don’t even have computers at home. I feel that asking 70 such students to all meet online at a specific time is asking for too much right now. I’m available online for virtual office hours during class and at several other times during the week.

My more advanced students have taken me up on this, but my elementary students have not.

The first assignment of the new online regime came in last week, and all but six students completed their assignment on time. I was very surprised that so many turned it in, actually, given that we had a large earthquake here in Utah the day it was due!

I gave all six an extension, and then contacted them by email. Two got back to me right away, noting that they fell behind, and have since completed the assignment. Two of the six are serial offenders: they are often late or skip assignments. It’s possible the other two are sick.

I’ve opened up all of the assignments through the end of the term, so if the students get a chance to work ahead, they can. Several of them have worked all the way to the end of the course, and I’ll open up the final exam early so that they can finish it.

There’s been a lot of talk among our faculty about proctoring and cheating and so on. For years I’ve given take-home, open-book, open-note exams; the average is around a 70%. If they are cheating, they aren’t doing it well. And this time around? I just can’t be anxious about it.

The most successful thing I’ve done so far is simply to send an email to every student “individually” (this is easy to do in the Canvas Inbox), just checking in, independently of any assignments.

They were very responsive to this and shared with me some of the things that are overwhelming them right now (pandemics, earthquakes, you know, the usual...). That was valuable to me to help re-calibrate my expectations.

I’ve always thought that my job is to leave them loving astronomy and wanting to know more. This semester, that goes double. More than ever, they need the perspective that only astronomy can teach them.

Classroom Stories: Light as a Wave

By Stacy Palen

Typically, I lecture about light as a wave by showing students images of waves and describing wavelength, frequency, and velocity. Then I tell them that wavelength and color go together; that light of a particular color has a particular wavelength.

However, when we would get to the Light and Spectra activity, it was clear that they had not fully internalized this information. Given that I’m not lecturing at all this semester, I invented a short activity (which can be accessed by clicking here) that unpacks this relationship a bit.

The activity uses an LED light tower that I happen to have. You can find this specific one here, but the activity could be adapted for use with spectral tubes or images from the internet.

I cannot darken the room this semester, so being able to adapt this activity made it indispensable. I also could not use the spectral tubes for my students because they simply weren’t bright enough to see. I wound up using the online images from the light and spectra lab. Without this activity students would not have been able to use their spectrum glasses in the classroom at all!

Oh, and in case you were wondering, no, it doesn’t work to try to project the spectrum tubes using the document camera.

Despite the difficulties in using the online images, student performance on the light and spectra activity was better than in the past. They also seem to have acquired a clear understanding that color and wavelength are related.

You can check out the activity yourself by clicking here!



Classroom Stories: More Ruminations on a Theme: Fermi Warm-Ups

By Stacy Palen & John Armstrong

This week, we have a guest post from a colleague at Weber State University. John Armstrong is also teaching in the inadequate classroom. He is experimenting with a way to fill the time while he figures out what’s changed about the A/V situation since the last class two days ago… 

Thanks to some intermittent multimedia issues in my new “temporary” classroom, I’m forced to get creative with the first ten minutes of class every day. So, I start by giving a Fermi problem to my students. I ask the question and they can work on the answer while I jiggle cables and try turning things off and on again.

Physicist Enrico Fermi was famous for posing seemingly unsolvable questions that he would then proceed to solve with a few back-of-the-envelope calculations. The most famous of these—how many piano tuners are there in the city of Chicago—requires some educated guesses about population, the popularity of pianos, and the diligence of their owners, but you get surprisingly close to the “correct” answer without knowing much of anything.

In astronomy, this tool has been leveraged in the Drake Equation to estimate the number of civilizations in our galaxy, proving that even when you can’t know some of the parameters you need to measure, you at least have a framework for study. The first three terms of this equation—the number of new stars formed in the galaxy, the number of these stars that form planets, and the number of Earth-like planets in each system—were largely unknown when I started my studies in the mid-nineties. They now have pretty good estimates. We are now on the verge of an estimate of how many planets can evolve life, which is something that could happen in the next decade or so.

But when I reached this point in my class, going from a simple Fermi problem to the Drake Equation seemed like a heavy lift.

I’ve always started the semester with a formal activity on estimating the number of pebbles in a jar. We measure the volume of the jar, remove a few pebbles and systematically measure their volumes, and then divide the two. The amount of agreement between the groups is surprising.

But thanks to my A/V woes, I’ve started asking a question every day. How much does the mass of humans increase each year? How far does a bumblebee travel in a day? How much food energy do you consume in a year? And each day, more and more students seem to dive in. Better yet, some of them have come in after doing some of their own estimations. How many bricks are in their house? How much electricity do they consume every year? 

The answer to the last question turns out to be surprising: It’s about ten times the amount of energy that you eat in food.

While I’ve always seen the value in Fermi problems, their routine application is giving my students extra practice and increasing their numeracy. And they also seem to be sparking my students' interest in their own questions.

I can’t wait to get to the Drake Equation!

—John Armstrong

Current Events: "Not Just A Space Potato": NASA Unveils "Astonishing" Details of Most Distant Object Ever Visited

By Stacy Palen

According to this article on The Guardian, when the New Horizons spacecraft arrived at Arrokoth, it revealed a surprising world. Now, planetary scientists are beginning to reconsider their conclusions about the formation of the Solar System. This new discovery appears to favor a gentler model of planet formation than the hierarchical model.

Here are some questions, inspired by the arrival of the New Horizons probe at Arrokoth, that you can ask your students:

1) Where is Arrokoth located?

Answer: In the Kuiper Belt.

2) Why can observations of Arrokoth yield information about the early Solar System?

Answer: Objects in the Kuiper Belt remain essentially unchanged since the Solar System formed. They do not have the same history of impacts and geologic processes as objects in the inner Solar System.

3) In your own words, state the hierarchical model of planet formation.

Answer: Small bodies smash together to form progressively larger bodies.

4) In your own words, state the cloud collapse theory of planet formation.

Answer: Slightly denser regions of dust and gas clump together and then, all at once, collapse under gravity.

5) What would astronomers expect Arrokoth to look like if the hierarchical model is correct?

Answer: They would expect to see evidence of collisions, like fractures and varied composition across the body.

6) What would astronomers expect Arrokoth to look like if the cloud collapse theory is correct?

Answer: They would expect to see uniform composition and no evidence of smashing.

7) Which model of planetary formation is supported by the actual appearance of Arrokoth?

Answer: Because Arrokoth is relatively smooth and uniform, it supports the cloud collapse theory of planet formation.

Current Events: 7 billion-year-old stardust is the oldest stuff on Earth

By Stacy Palen

I recently stumbled upon this article from The Washington Post about stardust on Earth. Mineral dust in the Murchison meteorite shows traces of neon produced by cosmic rays as the dust traveled through space. The abundance of neon atoms indicates that the dust was formed 7 billion years ago—before the Sun formed.

Here are some questions to ask your students based on the article:

1) What produces neon atoms in grains of interstellar dust?

Answer: Cosmic rays smash into the grain and convert silicon into neon.


2) How does the rate of cosmic rays striking the dust change with time?

Answer: It doesn’t. This rate is constant.


3) Suppose that one grain of dust has twice as much neon as another grain. What can you conclude about the relative time each grain spent in space?

Answer: The one with twice as much neon was out there twice as long.


4) In your own words, describe how astronomers determine the age of a grain of interstellar dust.

Answer: Astronomers count the number of neon atoms and compare that number to the number of neon atoms in a grain of known age. If there are more neon atoms, the dust grain was roaming the galaxy longer.


5) How old is the Sun, and how do we know?

Answer: The Sun is about 4.5 billion years old. We know this from measuring isotope abundances in moon rocks.


6) Are these dust grains older or younger than the Solar System?

Answer: These dust grains are 2.5 billion years older than the Solar System.


7) Is this result consistent with the idea that stars recycle material from the interstellar medium when they form? Explain.

Answer: Yes! Because the Sun and planets formed from material lost from earlier stars (we know this because of the abundance of other materials. Some of that material is still floating in the Solar System, and some of it was lost from stars that died long before the Solar System formed.

Classroom Stories: Another Way to Do the Phases of the Moon

By Stacy Palen

The phases of the Moon are one of those topics that has been extensively studied by the astronomy education research community and is well-known to be more complex than most people think. There’s the change of perspective from Earth-view to space-view. There are multiple motions at once (the rotation of Earth and the Moon, and the revolution of the Moon around Earth). There’s the issue about light rays always traveling in straight lines and not bending. It’s complicated.

Last week, I pulled an old phases-of-the-Moon activity out of the archives, which can be accessed by clicking here, for my students to complete in addition to the activity, “Studying the Phases of the Moon” from the Learning Astronomy by Doing Astronomy workbook. This is not an appropriate activity for Learning Astronomy by Doing Astronomy because it requires students to have Styrofoam balls that have been colored black on one half. (I can’t make the classroom dark, so I can’t use the traditional “balls-on-sticks” approach.) But one thing that I like very much about this activity is that it leads them to figure out how to (approximately) tell time by the Moon, which means that I can ask them a question about it on my zombie-apocalypse midterm—insert evil laugh here!

The activity also asks them to consider the phases of other objects, such as the phases of Earth as seen from the Moon, or the phases of Deimos as seen from Mars or Phobos. Carrying the concept of phases away from Earth seems to help cement the idea that this is a phenomenon that is all about the relative location of the light source and the observer.

I followed this activity the next week with the “Studying the Phases of the Moon” activity from the workbook. I was interested to notice that students finished the activity in record time and were much better prepared for it. The two activities worked well together to really build their picture of how the phases of the Moon actually occur.