Posts Tagged ‘Astro 101’

An Astrology Interview that gets Us Nowhere

January 20, 2011 10 comments

It started with a brief email from a local news reporter asking if I was interested in speaking about the recent viral news for a 13th zodiac sign. Sure, why not I thought. So I immediately replied. No kidding, within 45 minutes of receiving the initial email I found myself in front of a camera, being interviewed about something I teach every semester in my Astro 101 class. (No I don’t teach astrology, but I do teach about constellations, the zodiac, and pseudoscience so naturally astrology comes up in the discussion.)

The interview went well.  Lisa Edge, the news reporter, and her camera man were very polite and asked very intelligent and directed questions. I answered them to the best of abilities and tried to avoid technical jargon.  After 15 minutes or so we were done. I thought things went well. So here’s what made the cut,

Okay, first off, I had no idea that they also interviewed a christian psychic. (WTF is that anyways?) I guess that’s okay because the news is suppose to be balanced. What gets me is all that great science material I gave her was lost to the editing floor. A bit of a consolation prize is that much of what she said as the story’s wrap-up is stuff we talked about.

The one question that she did ask that I wish would have survived the cut is, “Do you think this news of a 13th zodiac sign is good for astronomy?” My answer was two sided (and probably why it got cut).

On the one hand, scientists are continually trying to educate the public about what is and is not science. On a regular bases we try to demonstrate how certain studies—and I use the term loosely—act scientific but in fact are not; astrology being one of the oldest examples. For this reason, when astronomers see astrology getting face time in the media we tend to roll our eyes and think here we go again. (For some entertaining blasting of astrology check out Astrological Sign of the Times, Astrology is Still Bullshit and the Universe Doesn’t Care About You, and This is why Horoscopes are Full of Assfog.)

However, there is the flip side. Although astrology plays the roll of a child at an adult only party, there’s still a teaching moment that we as educators can seize upon. Here we have so many people listening and interested in learning about a topic closely related to astronomy and most of the professional astronomy and science educators communities are turning their backs. Instead we should take this time to educate and to demonstrate why the 13th zodiac sign is nothing new. Why astronomers have known for ages that everyones astrological sign is off because of the Earth’s precession. Why astrology is considered a pseudoscience. Ultimately this is why I did not hesitate to give the interview. While most of the science was lost in the editorial process, and I knew it would be, I still tried to get through a little bit of scientific knowledge.

For the record, I have also posted an extensive blog entry on this whole zodiac issue: The Zodiac Shuffle According to Astronomers. This entry is meant to briefly explain the science behind the 13th zodiac sign and why most everyone’s astrological sign has shifted.  For another reference, check out An Astronomer Looks at Astrology by Andrew Fraknoi.

The Science Illiteracy of Bill O’Reilly

January 8, 2011 2 comments

Recently the president of the American Atheists, David Silverman, appeared on the O’Reilly Factor. Silverman was invited on the show to discuss the billboards sponsored by the American Atheists. To some, as O’Reilly is quick to point out, the messages proclaimed on the billboards can be interpreted as offensive. Before going further, I want to be clear that this posting is not about the American Atheist agenda. It’s about Bill O’Reilly’s disappointedly poor understanding of Astro 101 science, which we can see in his interview of Silverman.

So Bill O’Reilly’s argument for God appears to be simple enough, “The tide goes in, the tide goes out. Never a miscommunication.” I’m not completely sure what O’Reilly is trying to say here, especially the part about the ‘miscommunication’. If I had to conjecture I would say that he’s trying to argue that natural phenomena, such as tides, are directly the work of God. This is really one of the classical arguments for God (think Greek and Roman gods, for example). Where O’Reilly fails miserably is in his selection of which phenomena he attributes to God.

The cause of the tides is well understood and has been for hundreds of years thanks to Newton himself. They’re the result of the gravitational pull from the Moon acting on the Earth. More specifically, the ocean tides happen because the gravitational attraction between two objects depends on their separation. The closer two objects are, the stronger the gravitational attraction between them. This means that the Moon pulls harder on the near side of the Earth in comparison to the center of the Earth. Likewise the center of the Earth experiences a greater attraction to the Moon than the far side of the Earth. The difference in gravitational attractions is what is referred to as tidal force. The tidal force ultimately manifests itself as a rise in the Earth’s liquid oceans. (For a more in depth description, check out Tides, the Earth, the Moon, and why our days are getting longer.) For those thinking on a higher level, yes, the Sun likewise produces tides, but at roughly half the extent the Moon does.

So back to O’Reilly. He picks a natural occurrence that is explained by science. In fact, it’s a level of science that’s taught in most any Astro 101 course, or even more likely, in a middle school earth science class. If O’Reilly was just a little bit more educated he would have asked a deeper question like, why does Newton’s gravitational constant have the value it does? Now there’s a question not necessarily outside the realm of science, but one that’s not readily addressed with our current state of knowledge.

Regardless, it’s clear that O’Reilly lacks an understanding of the tides. What’s worst is that he challenges Silverman to explain the tides, as if an understanding of such a concept is beyond the understanding of the human mind. O’Reilly repeatedly states, “You can’t explain that.” This is where I fly off the handles.

The point of science is to construct self-consistent models that allows us to explain past observations and to make testable predictions about the future. Tides fall well within this scope. We have a model for the cause of the tides. We can predict times for future high and low tides. We can even observe tidal effects on distant worlds. It is science! But for O’Reilly he seems content to assume an explanation for the tides that appeals to a supernatural being. Moreover, he appears to even think that it cannot be explained otherwise.

What annoys the pooh out of me is that he has no apparent interest in learning about science. His religious beliefs are preventing an understanding of Nature. So what’s the harm in this? Isn’t he entitled to his own beliefs? Consider the recent story about congressman John Shimkus. According to Shimkus, “The planet won’t be destroyed by global warming because God promised Noah.” Here we have a person in political power that has a direct voice in environmental policies that may or may not lead us on a destructive path, and yet he’s outright discounting science for his own religious beliefs.

Obviously these individuals have placed a personal belief in one particular religion so high that they’re willing to discount a rational explanation based in science. To these individuals I say, Nature is going to do whatever it wants to do. We can either construct useful models in an attempt to understand how Nature works, or we can take the O’Reilly/Shimkus approach of blindly assuming the unknowable workings of a supreme being. One approach allows for progress in information sharing, extending life expectancies, knowledge about our place in the Universe, etc, etc, etc. The other approach … well I’m not sure what they expect out of it.

Of course, O’Reilly’s comments have led to many WTF’s moments on the web and on television. One of the best comes from Steven Colbert on The Colbert Report (Bill O’Reilly Proves God’s Existence – Neil deGrasse Tyson).

As usual Colbert makes insightful and whimsical remarks. His summary of O’Reilly’s argument for the existence for God is just perfect, “There must be a God because I don’t know how things work.” Most importantly, The Colbert Report attempts to educate the public about how the tides really work by having a well known astrophysicists, Neil deGrasse Tyson, describe their cause. For that I thank the show.

By the way Bill O’Reilly, here’s another argument for God, as suggested by the American Atheists, Inc Facebook page, “Food goes in… poop comes out. No miscommunication! You can’t explain that!!!”

Observations of Mice, Err Students, in Lab

October 15, 2010 Leave a comment

We’re now slightly past the halfway point in the semester.  In fact, today is Fall Break.  Students are given the day off before starting the push into finals (or more realistically the push to Thanksgiving break).  In Astro 101 we just had our second exam, which I guess I’m justified to actually call a midterm.  We’ve also completed about half of the labs for the semester.  It’s this second milestone that I want to comment on.

Labs had been going smoothly until we reached the most recent laboratory exercise.  I’m not completely sure what happened but there was just short of a mutiny when I assigned students the task of calculating Jupiter’s mass.

To give context to the problem let me first make some comments.  At Coastal Carolina we teach Astro 101 using the SCALE-UP model.  In the SCALE-UP approach, students meet three times a week for two hours at a time, as opposed to meeting three times a week for an hour and having a separate three hour lab at a different time.  The SCALE-UP model allows us to complete labs at the exact moment the lecture material dictates.  To maximize the idea that the labs are meant to address and reinforce difficult concepts, the labs have been written in-house with the student learning objectives for the course as guides.

Now to the problem with the most recent lab.  So far the five labs we’ve completed are

Lab 1 – Introduction to Starry Night™: In this lab students played around with the planetarium program Starry Night™.  During the lab students investigate a number of common misconceptions about astronomy, such as the uniqueness of the North Star, what really is the zodiac, and the fact that the Moon can be above the horizon during daylight hours.

Lab 2 – The Celestial Sphere: For this lab students are given a celestial sphere globe and asked to explore such concepts as the diurnal and annual motion of stars, the seasons, and what it’s like to live above the arctic circle.

Lab 3 – Solar and Lunar Motions: To study solar and lunar motions a 150 watt lightbulb is placed in the middle of the room to represent the Sun.  Students are given earth globes and styrofoam balls (which represent the Moon) and are asked to study the effects of the seasons, lunar phases, and eclipses.

Lab 4 – Kepler’s Laws: This lab explores each of Kepler’s Three Laws of Planetary Motion, one after another.  For example, students are asked to draw and compare ellipses of various eccentricities and semi-major axes; calculate the swept out areas over different portions of a planetary orbit; and verify that the eight planets do in fact obey the Third Law.

Lab 5 – Measuring the Mass of Jupiter:  For this lab students are guided through the process by which astronomers measure the mass of a celestial object.  Specifically, in the lab we use the orbital properties of the Galilean moons to measure the mass of Jupiter.

One of these labs is not like the others.  The structure for the first four labs was to use a central theme, or set of laws, to explore a variety of concepts.  In Lab 5, however, the task was to do one thing, measure the mass of Jupiter.

In writing Lab 5, I tried to break the measuring process into smaller, bite-sized steps.  Nonetheless, the process still required a set of sequential steps to achieve one end goal.  Along the way students ran into difficulties, such as realizing the sum of Jupiter’s mass plus the mass of any of its moons is, to a very strong approximation, just the mass of Jupiter.

Based on my observations of students completing the exercise and post-lab discussions with students, I think the overall ill will toward the lab arose because the lab required a dependent sequence of tasks.  If students became confused at any point along the way they would become frustrated and would in turn get less out of the lab.  In the other labs, the modulated approach meant that if a particular section was confusing, a positive outcome could still be attained through the other, less confusing sections.

This is only my hypothesis but it’s an interesting question.  Should we, as educators, task our students to complete smaller, modulated labs or is it acceptable to expect them to complete a long lab with one central goal?

The answer to this question is not trivial.  In many ways it depends on the audience.  For a science majors class, such as a calculus-based physics, it may be acceptable.  In these classes we want to instill in students the process by which scientists poise a question, and address the question through a designed experiment.  For a class of non-science majors, like Astro 101, maybe the modulated approach is better.  Here, at least in the style of labs I’ve elected to adopt, the goal of the labs is to support the lecture material through an emphasis on and a thorough analysis of difficult concepts.  The goal is not to design or replicate a traditional experiment.

It would be interesting to investigate the different approaches to see if one approach versus the other create greater gains in a laboratory course.

It’s a Small and Big World After All

October 14, 2010 15 comments

In my opinion, one of the most difficult concepts for non-sciencitists to grasp is the vast range of sizes needed to describe the objects that fill our Universe.  In teaching Astro 101 I work hard to instill in my students a sense of how big the Universe really is.  It’s not a trivial exercise for humans to get to the Moon, or to Mars, or ideally to another star.  The reason being, there’s a lot of space in outer space.  Unfortunately I don’t have time in Astro 101 to also impress on students how small the world of particle physics is.

Personally it still amazes me that the smallest length of interest in physics is the Planck Length at an astonishingly small value of

0.000000000000000000000000000000000016 meters.

Conversely, the observable Universe is a whopping

140000000000000000000000000 meters

in radius.  That’s a huge range is sizes!

In between these two extreme sizes is EVERYTHING and science attempts to model all of it with just a handful of theories.  To get you thinking about the wide range of sizes that scientists grapple with on a daily basis take a look at the Scale of the Universe.

To me it’s so cool that astrophysics can use basically electromagnetism and Newtonian mechanics, with the occasional appeal to Einstein’s relativity, to describe just about any macroscopic motion.  On the other hand, quantum mechanics (and statistical mechanics if you want to split hairs) does a really good job at describing the microscopic motion of particles.  With just these few theories, everything represented in the Scale of the Universe can be understood.

The Astro 101 Textbook Dilemma

October 1, 2010 2 comments

It’s that time of the semester where we’re looking ahead and thinking about what the next round of classes brings.  Yesterday, the Physics faculty had our biannual meeting where we assign instructors to classes.  I’m teaching Astro 101, as expected, in addition to the first semester calculus based physics course.  Now that we have our teaching assignments, the next step is to decide on a textbook for adoption.  For the introductory physics class, I don’t have a choice on the matter.  The faculty have already agreed on a particular text that we’re going to use for a few years.  (By adopting a text for multiple years we can save the students money via end of term book buybacks.)  For Astro 101, where I’m the only person teaching the course, the book selection process is all up to me.

Chaisson & McMillan - Astronomy: A Beginner's Guide to the UniverseI’ve wrestled with the problem of choosing an Astro 101 textbook for a number of years now.  When I started as an assistant professor back in 2007 I adopted Chaisson & McMillan’s, Astronomy: A Beginner’s Guide to the Universe for reasons that I’ve since forgotten.  At that time I had no prior teaching experience, let alone with Astro 101.  I was fresh out of a research postdoc and what little teaching I did in graduate school was as a teaching assistant—basically I taught lab sections of a course someone else designed.  In outlining the course I had nothing to go off, only the course description.  For this reason I modeled my class after the text. The book’s table of contents became my guide to what was covered in class every day. I’m embarrassed to say this, but I was simply trying to survive as a faculty member.

Since those days, I’ve attended a number of teaching workshops and meetings, and I’ve been exposed to the astronomy education research literature.  In response, my class has changed drastically.  Most importantly I’ve moved away from following a textbook’s table of contents as my guide and I’ve written original course learning objectives.  In redesigning the class I’ve found that the material I want to cover is not distributed in the same way as any Astro 101 textbook I’ve seen.  The most notable example is that I spend the first third of the class covering celestial sphere ideas: diurnal and annual motions, the seasons, the ecliptic, lunar phases, synodic vs sidereal etc.  In most textbooks, all of this material is relegated to a chapter at best.  Some topics I cover may only get a few paragraphs of coverage in a typical introductory astronomy textbook.

On the other hand, when I cover topics such as the Hertzsrpung-Russell (HR) diagram, most texts cover the material to a much greater depth than what I expect from my students.  Moreover, the material is often presented in a language that I don’t necessarily use.  In my class I try to minimize—but not completely eliminate—topic specific jargon.   Also, these texts have sections and even chapters of material that I don’t cover in a one semester survey course.

This finally brings me to the question of choosing an Astro 101 textbook and where my dilemma lies.  Coincidentally there’s an ongoing exchange on the astrolrner yahoo group discussion board about this very topic right now.  I don’t want to use this blog as a reply to the comments there, but I do want to partially highlight the comments made by Tim Slater.

I know that some folks have tried using trade books or coffee table books or extensive fact-based web sites. Although these are attractive, particularly in how they are illustrated, they lack the tried-and-true pedagogical tools that many, many students, publishers, and authors have worked through and tried to perfect over the years – explicitly stated learning goals, headings to structure student thinking, end of chapter summaries with review questions, and, gasp, even bold faced words to help focus student attention.  I’m not saying that these things are perfect and are not often overused, BUT, what I would say is that these pedagogical clues are important enough to student readers that having them in a textbook is more important than the pretty pictures and pedagogy-less writing of coffee table books. As it turns out, textbook features DO help students learn better!

He makes a very good point.  Textbook authors, Slater being one of them, have now incorporated astronomy education research supported methodologies into their texts.  This is what distinguishes textbooks from run-of-the-mill astronomy books you find at a bookstore.  More importantly, as an instructor, these unique features are desirable in a supporting text for a class.  It’s also one of the reasons I want to adopt a text for my Astro 101 course.

However, and this is where I begin to have difficulties, although the goal of any of these textbooks is to teach astronomy they go about it in very different ways.  When an author decides to write a textbook they have to decide what content to cover, to what extend, and using what presentation strategies.  These choices are made by first deciding what are the learning objectives—statements about what a student should be able to do after using the text.  Once the learning objectives are decided, the text is written to support those goals.  For example, some text have the learning objective to instill in the students the ability perform certain calculations, while other texts have learning objectives focused on conceptual understanding.  The learning objectives can be very broad—like the examples just give—or they can be very narrow in the case of learning objectives for a particular chapter or topic.

Now the questions arise, if the textbook’s learning objectives don’t align with the course learning objectives should the book be adopted?  If no textbooks’ learning objectives align with the course’s learning objectives, should any text be adopted?

Lecture-Tutorials for Introductory AstronomyI’ve taken the point of view that if no textbook’s learning objectives align with the course learning objectives, then I won’t adopt a text.  In the Astro 101 course I teach at Coastal Carolina (ASTR 101: Conceptual Astronomy) I’ve adopted the Learning-Tutorials for Introductory Astronomy by Prather et al. as the only required text.  This particular book is a collection of astronomy education research developed interactive tutorials that are designed to get students actively engaged in the material through peer work.  In making this the only required text I’ve put the unfortunate burden on my notes (presentation slides) as being the only source of new information.  All definitions and facts come solely from what I deliver to the students.  This is an issue I’ve come to recognize and another reason I would like to adopt a text.

As I see it, the alternative to not adopting a text is to go ahead and adopt a text that has different learning objectives, a different distribution of topics to cover, more information on some topcis, and at a higher cost to the students than what I want.  A second alternative is to restructure my class to teach along the guidelines set forth by a text.  For reasons that deserve another blog entry, I don’t like the second option.  A third alternative is to compromise and to find a book close to my desired learning objectives.  With this path, I’m pushed into the issue of content distribution.  I have yet to find a textbook that distributes the material coverage in the way that I like.  I don’t want to assign a text to my students (that may be in excess of $125) but only use 10% of the material.  It’s not fair to the students.

So here I stand with a desire to adopt an Astro 101 textbook, but without a justification for doing so.

The Danger of Showing Seemingly Obvious Representations

July 30, 2010 Leave a comment

Recently I read the article

Student Ideas about Kepler’s Laws and Planetary Orbital Motions, K. C. Yu, K. Sahami, & G. Denn, Astronomy Education Review 9, 010108 (2010).

The article covers pre-instruction interviews of students entering a university level Astro 101 course.  Specifically it looks at student knowledge of Kepler’s Laws during the first week of class in an attempt to find common misconceptions that could be addressed through curriculum reform.  The results of the study are not surprising.  A student enrolled in an Astro 101 type course doesn’t have adequate knowledge of Kepler’s Laws prior to instruction.  If they did, then Astro 101 probably isn’t the right class for them.  I would expect the same general result from a study of pre-instruction knowledge on the conservation of angular momentum given to students about to take their first semester of introductory physics.  (Yes, I chose that example on purpose.)  The authors also discuss an interesting point that made me rethink my own teaching style.

According to their findings a substantial fraction of students have a preconceived notion that planetary orbital shapes are highly eccentric.  The authors speculate that the origins of this misconception is in commonly found representations such as the one shown below (and taken from their paper).

Skewed perspective of the Solar System

As a seasoned astronomer I immediately recognize this image as a skewed view of the Solar System.  However, to someone less experienced there isn’t an obvious reference marker to inform the viewer of the upright direction.  The result can be a personalized model for the Solar System in which the planets move on highly elliptical orbits.

This got me thinking about my own teaching.  I use Keynote presentations filled with images and diagrams.  Some of the pictures I use are pirated from the internet or from a textbook.  In selecting these images I usually give them a cursory glance, often with me looking for a particular feature that I want to explain in class.  However, as the above discussion implies, an apparently harmless image may have lasting effects.  Even of more concern is that a typical student in Astro 101 is done with science after this class.  Therefore, any misconceptions left after the final exam may stay for some time.

The point made in the paper reminds me of the importance of putting myself in the student’s frame of thinking.  A picture or diagram with a seemingly obvious meaning can easily be misinterpreted.  The misinterpretation can be overlooked by an expert because we haven’t considered this point of view in many, many years.  I guess the message I have is it’s always a good idea to take note of what’s being expressed in each figure used in a lecture.  There will be times where constraints require the use of a less than perfect image.  In such cases, it’s important to take the time in class to explain what’s going on.

I know one of my personal pet peeves is when someone presents a plot without explaining the axes.  How am I to interpret the data if I don’t know what’s being plotted.  In a similar vein it’s important in teaching that if an picture is worth including in the lecture then it’s important enough to clarify what exactly is being shown.


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