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March 2020

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.