The Classroom Astronomer Digest, April 2022
Making Astronomy Games; Einsteinian Physics in Middle School; Indexed Online Labs Resource; 2-Week Summer Student Observing; Mars Eclipse Experiment; Making WWT Tours; Testing in-Dome on Sky Motions
Cover Photos - Astronomy Games and…
…Phobos Eclipse Experiment for Students
In This Issue:
Cover Photos - Astronomy Games and Phobos Eclipses the Sun
Welcome to Issue 24 - Best Laid Plans….
Connections to the Sky -
- Making a WorldWide Telescope Tour- Astro Labs Resources DeLuxe
- Observing Workshops for Graduating HS Seniors and Undergraduates at Mt. WilsonAstronomical Teachnique- What Can You Do With a Martian Eclipse?
The RAP Sheet – Research Abstracts for Practitioners
- Designing Physics Board Games: a Practical Guide for Educators
- A Comparison of Short and Long Einsteinian Physics Intervention Programmes in Middle School
- Identifying Students’ Mental Models of the Apparent Motion of the Sun and StarsThe Galactic Times April Inbox Magazine Highlights
NOTE: All stories have been truncated from their original lengths to fit in the Digest. Full lengths are available to Full Subscribers in the Archive on Substack.
Welcome to the April Digest for The Classroom Astronomer Inbox Magazine!
Best Laid Plans…
So there I was, staring up into the sky, or rather, the Sun…..and strangers’ faces.
That wasn’t my planned activity. I was actually on my way to a store to look for a new paper shredder. Instead I ended up (improperly) stair-ing into the junction in physics between gravitational potential energy converted to kinetic, rotational motions, and inelastic collisions with concrete.
Thus explains the delay in publication of the second April issue of TCAN. And the somewhat mangled digits that aren’t in the best condition if you want to type on a laptop. Fortunately—so far, anyway—there doesn’t appear to be anything more worse off than kerfluffled fingers, but …. 1g is a b****….
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This is a pretty spacey issue! We reproduce a classic solar eclipse experiment, with a little history, but on Mars. In the RAP Sheet, a very recent (this month!) research article on a new assessment for use IN planetarium domes brings highlights and a suggestion on how to teach about solar AND stellar motions in the sky. Another RAP article is on how to create science games that are valid educationally. And we return, both happily and unhappily, to the Tours of the WorldWide Telescope. Happily because there are better instructions (you won’t get them on the website), but the programming still….vacuums……
Besides the, um, physics demonstration, April was a 2-issue month anyway. In fact, this is the slow conference season but I’ve been in contact with all the people doing conferences we virtually attended last year. Some had decided to go nearly all in-person events but have since backed off to being very hybrid, or both in-person AND streaming all sessions, too. Conferences will begin in earnest in June so more 3-issue months will be in the second half of the year than the first half, it seems. More material to publish, especially for the Astronomical Teachniques column. Yay!
And after I wrote this back in late March, I was able to add one more—the Italian Planetarium Association’s meeting, for which I’ll have at least one story in the Full Subscriber’s first May issue! Plus, working on a poetry and some VR to teach astronomy stories, what you can do educationally with the upcoming total lunar eclipse (last one in the USA that can be seen from start to finish for three years!), and hope to get back to remote observing. Don’t want to wait, or read truncated Digest versions? Then, subscribe to the Premium version to read it!
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Key websites: Homepage for The Classroom Astronomer, with its index to all Inbox Magazine issues’ contents, by celestial object, educational subject area, grade level or venue, and with complete Tables of Contents http://www.classroomastronomer.com .
The ultimate home of our Universe — Hermograph Press — has its homepage at: www.hermograph.com and its Store, for educational materials and books, is at: www.hermograph.com/store .
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Publisher -- Dr. Larry Krumenaker
Connections to the Sky
Making A WorldWide Telescope Tour
As mentioned in a recent TCAN issue, a previous article on creating Tours on the WWT has a link that users should ignore…because it is very dated and erroneous in its instructions, the feature of the WorldWide Telescope that is of good use for educators. It is kind of a super PowerPoint using ‘real’ sky images.
I inquired of the American Astronomical Society, which owns the site, and their main guy, Peter Williams, sent me a link (available to Subscribers only) with much better instructions. It is not available on the Website, but ought to be.
I decided to test it out using as a template the article in TCA #20 on “eyeball spectroscopy,” using star colors to detect stellar temperatures. With a lot of hassle, I did manage to create a four-slide Tour on the different star colors in the Big Dipper stars. Nothing fancy, no music, animations, links to other webpages, narration, just text and graphics.
It should be easy. You start by hitting the tiny down arrow under Guided Tours, then selecting Create a Tour. You fill in Title, description, name and email (you can edit these later), and Add a Slide. In that, to the right, you can put in a picture from your computer, add text, graphics like arrows or circles, move to a place in the sky, and when done, Save. Then add another slide. The programming handles the transitions. If you are an WWT member, it saves the file online. If not, you have to save to your computer.
I have to say that I’m fairly competent in graphics programs and the like, but this service still has a lot of bugs. It had a tendency to jump to the wrong slide in the sequence when editing. Often, the last slide would not be *allowed* to be edited, jumping back to the first slide when selected. Frequently, though I saved the slides (that’s what the Save button does, saves THAT particular slide), it did not save the TOUR to my disk. I had to manually copy my most recent online saved version to my desktop. Other times the mouse would lose track of where it was, and move the star field, instead of the graphic arrow or text box, and I had to recenter everything. I had to redo the entire four-slide Tour too many times. And once you DO save to disk, despite the “Open to Edit” checkbox, if you want to go back and make a change….nope, you can’t—before uploading to our website, I found two typos I wanted to fix. I would have had to redo the four slides all over again. It simply would allow replay but not edits. So I would have uploaded my effort for you to see, but didn’t. Oh, and try to upload a file with a changed name to your website?; WWT disowns it.
Perhaps you might wish to spend more time with this than I would. I’ll wait for them to perfect the system. Given how far behind they are on updating the instructions, I’ll take screen captures and continue to make PowerPoints.
—LK
Astro Lab Resources DeLuxe
A few issues back we posted a small list of massive collections of which there was an early listing of 21 free university astronomy online lab sites as resources, by the prolific list-maker Dr. Andrew Fraknoi. Now he has created what might yet be his most useful project, for instructors at the university level at least, though others can surely find items of value. He has turned that list of universities into an annotated and indexed list of astronomy lab activities, organized by the chapter headings in the popular OpenStax introductory astronomy textbook. The 30-page PDF contains links to labs from those 21 universities which includes, as he puts it, “paper and pencil projects, computer work with up-to-date apps or the free Stellarium planetarium program, and activities that get students outside to observe with eyes, binoculars, or telescopes.”
Chapter 7: OVERVIEW OF SOLAR SYSTEM, DATING METHODS
7.1 Overview of Our Planetary System
7.2 Composition and Structure of Planets
7.3 Dating Planetary Surfaces
7.4 Origin of the Solar System
Comparative Planetology (learn from planetary data, make categories of planets) – from the York College (CCNY) lab manual (Lab 7): https://www.york.cuny.edu/earth-and-physicalsciences/physics-lab-manuals/astr140-lab-manual-4e.pdf/view
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This listing is a useful resource, properly indexed by concept AND with a one-line description so an instructor can get a basic idea if the lab would be on the subject he or she can use. Nicely done, Andrew.
Get to it at this URL….. Andrew Fraknoi's Annotated Lab Activities Index
Student Opportunity to Observe With Big Scopes for Two Weeks
Here is an opportunity for high school graduates through undergraduate students, a summer observational astrophysics program at Mount Wilson Observatory (MWO). Formerly CUREA, now called SOAR@MWO, this two-week residential program is now open to college-aged or college-bound participants at least 18 years or older by the start of the program. Participants engage in classroom and hands-on work in Week 1 to learn techniques in solar spectroscopy and stellar photometry, astrometry, and spectroscopy. They then apply these skills in Week 2 to an observing project of their own design, collecting, analyzing, and reporting on their own data.
More details of the program, including program cost and application information, are available at https://sites.google.com/a/kenyon.edu/mwss/ or email Paula C. Turner, turnerp@kenyon.edu, Professor of Physics, Kenyon College.
Astronomical Teachnique
What Can You Do With a Martian Eclipse?
On April 2, 2022, Mars’ bigger moon, Phobos, passed in front of the Sun, observed by the latest Mars Rover, Perseverance. In a video’d event that lasted a whole 40 seconds, the ‘doomed potato moon’ passed completely over the Sun’s disk causing a sloppy annular eclipse. This wasn’t the first time we’ve witnessed a solar eclipse from Mars, but it was perhaps the best recorded one.
With a lot of hoopla coming up concerning two solar eclipses that will cross the United States in 2023 and 2024, it does bring up the question of what can you do with eclipses educationally, other than enjoy the awesome views? A second question might be how can we use a Martian eclipse educationally?
If you are in direct line on Earth with Sun and Moon you get either an annular (ring-shaped) eclipse or a total eclipse (fully blocked solar disk) depending on whether the Moon is or is not far enough in its elliptical orbit to do the full light blocking. Because the Sun is a disk, not a point source of light, the Moon’s shadow has a dark central cone, the umbra, and a lighter surrounding shadow field called the penumbra where a partial eclipse is seen on Earth, and some sunlight gets through. If you are in the umbra, you get a total eclipse. If the Moon is too far, the umbral cone doesn’t reach the Earth’s surface and the shadow on the Earth is ALL penumbra; you’ll see an annular-ring eclipse, some sunlight obviously getting through and you’ll be in a penumbral kind of situation.
On Mars, ALL eclipses are penumbral, because both Phobos and Deimos are too small to cover the Sun, though Phobos makes a decent attempt at it. Its umbral cone never reaches the surface, but its penumbral shadow can be quite large in comparison. In fact, its shadow is larger when it is not over the head of the observer but when the eclipse is a horizon event.
For Phobos, many days can have two, even three eclipses at the same location!!
For the record, Deimos has about 130 eclipses a year, they last up to 2 minutes, and being smaller and farther away, they resemble planetary transits, like those rare ones of Venus, in appearance. Phobos’ can cover up to 38% of the Sun’s visible surface, though 20% is more typical.
The Classic Experiment: When we have an eclipse on Earth, we would know some things automatically. The Moon’s angular size would equal, more or less, the Sun’s. That would also make the the Sun’s distance from us the same proportion as the proportions in sizes. If we could determine the relative sizes and one distance, we could determine the remaining factor. The main reason behind this is the fact that the Moon’s umbra is essentially the same size as the Moon’s distance from Earth. Geometrical proportionate triangle principle.
Moon diameter/Moon distance = Sun diameter/Sun distance
Our issue Cover Photo shows the recent eclipse at maximum coverage. The largest “potato dimension” is about 50% of the Sun’s width. What could a hypothetical Martian school student do with this? Let’s try a ‘back of the envelope” calculation….and using for convenience, Earth units….and the logic of the Earth experiment.
Doing It On Mars: Phobos’ diameter is 27 kilometers (km), long dimension; it is not spherical. It is about 8000 km above Mars. [It would be fairly easy for a Martian to calculate these with trigonometry by observing this close-in world from two places at the same instant, gaining its distance from simple surveying techniques, and then using its apparent size of about 10’ (minutes of arc) seen from the surface to gain its actual size.] Given that during this eclipse that long-diameter was about half the Sun’s diameter (easy to measure) the umbral cone must have stopped halfway in towards Mars; for Martians to get the same total eclipse as us, Phobos would have to be twice as big. Let’s pretend it is for a moment.
You’d have the first half of the equation then as 54/8000 = Sun Size over Sun distance.
You need one of the latter two to get the other. The real first measures were when the Astronomical Unit, the Earth-Sun distance, was determined with the transits of Venus. Given Mars’ small diameter and farther distance, a transit of Venus or Earth would be painstakingly small, but presumably possible. Measuring the Sun’s diameter directly just really isn’t done.
Let’s assume some transit has determined the distance to the Sun from Mars, which would be an average of 227 x 10^6 km. (Mars’ orbit is quite eccentric; in the real world we’d have to do this with the distance of Mars on the exact date of the eclipse, but for this ‘b-o-t-e’ experiment, we’ll let that pass.)
54/8000 = Sun Diameter/227x10^6 ==> Sun Diameter = ~1.5 x 10^6 km, about 100,000 km too large, but good enough for a good grade, yes?
For a fascinating discussion on Phobos’ eclipses and seasons and how they are used to locate landers on Mars, see this article in the Journal of Geophysical Research Planets, by Bruce Bills and Robert Comstock from April 2005, Spatial and temporal pattersn of solar eclipses by Phobos on Mars. It is free, very mathematical but filled with interesting eclipse nuggets.
The RAP Sheet – Research Abstracts for Practitioners
What’s in the scholarly astronomy education journals you can use NOW.
A. Cardinot, V. McCauley and J. A. Fairfield. (2022). Designing Physics Board Games: a Practical Guide for Educators, Physics Education 57, 13 pages, May. Open Access. https://doi.org/10.1088/1361-6552/ac4ac4
This is not an astronomy-themed education article, per se, though some is mentioned in the article. But though it is focused on physics, it would be useful to astronomy educators as well. As it is Open Access as well, available via the DOI link above as well as through the Physics Education journal publisher’s home page, this is a worthy 13-page PDF to download if you are looking for a resource to download for making games for educational use in your classroom. Educators are quite lacking in game theory and game design in their training; this is a good first place to gain some knowledge.
To accomplish this, the authors developed six design principles that they feel are essential for creating meaningful and effective educational games to support the classroom instruction of science. And five design steps, shown in the figure below with questions to ponder and act on, are Empathise, Define, Ideate, Prototype, Playtest.
In addition to a physics and astronomy game the authors created, listed in their references (see Cover Photo), they list a number of other science games. For those looking for astronomy games, the authors review three: Terraforming Mars, NASA Space Voyeurs, and Planet.
2. R. Choudhary, A. Foppoli, T. Kaur, D. Blair, R. Burman, and M. Zadnik. (2022). A Comparison of Short and Long Einsteinian Physics Intervention Programmes in Middle School, Research in Science Education, 52, pp. 305–324 (print; July 2020 online). https://doi.org/10.1007/s11165-020-09944-8
An excellent review article by Australian researchers on the slowly increasing efforts to teach Einsteinian concepts versus Newtonian physics concepts. Some of their findings in historical overview were that Einsteinian physics (EP they call it) is more readily accepted by students if it is actually taught before Newtonian concepts are fully ingrained. They list core topics that are, and they feel should be, taught in schools in a table.
3. H. Bekaert, H. Van Winckel, W. Van Dooren, A. Steegen, and M. De Cock. (2022). Identifying Students’ Mental Models of the Apparent Motion of the Sun and Stars, Physical Review Physical Education Research 18, 18 pages, April 20. Open Access. https://doi.org/10.1103/PhysRevPhysEducRes.18.010130
There are a fair number of test instruments for astronomy classrooms but few for planetarium classes. Here’s one for those of you in planetariums! It is called AMoSS, Apparent Motion of the Sun and Stars and it is part of these Belgian authors’ SLOPE project: Study Learning Opportunities in a Planetarium Environment. In this study, they wanted to know their students’ knowledge of the differences and similarities between these two motion sets, day and night motions caused by Earth’s rotation and revolution, latitude and tilt. In this case, determine the mental models of 16-17-year-old Belgian students.
Some of the results they found include:
In student views, stars do as the Sun does, OR with longer nights, stars go higher in the sky, OR other than stars also going East to West, students can’t answer the questions.
The knowledge of Solar motions is definitely better understood than stellar.
Students do not apply Earth’s known motions that make the Sun do what it does to the stars!
How latitude and tilt effect stellar positions seems to be disconnected from how it effects solar positions no matter what time unit is involved.
The Galactic Times Inbox Magazine April Highlights
TCA’s sister publication. Twice a month, on the 1st and mid-month, with the following columns usually, plus occasional other articles. Here is what was in April’s issues. What will be in May’s? Find out by Subscribing to it here! It’s Free!·
Cover Photos — A New Way to Make a Jupiter
— Rings of DeathThis Just In —
* Um, That Really Wasn’t an Alien Invader After All…
* Neptune’s Summer Hot Spot
* Recipe for Making a Jupiter…First, You Stir the Pot…
* Death Throes of a Red Star (Cover Story)* Space Missions and Astronomy Research Facilities Contribute Heavily to Climate Change??
* Pluto’s Not Quite Dead Inside Yet
* Hello, Earendel! Farthest Star Ever?…
Sky Planning Calendar —
* Moon-Gazing
* Observing—Plan-et* Border Crossings
Astronomy in Everyday Life - Porrima, a Star of a Prophetic Ship
- It’s my 37th Year Orbiting the Sun….What Do They Call That on Mars?