The Learning Critical Thinking Through Astronomy Activities

I am somewhat limited in what I say in this post because I don’t want to give anything important away to students who find my blog (not that I care if they do).

It occurred to me today that a post describing my astronomy course materials might be helpful for anyone considering using them or wanting to know the underlying philosophy and purpose for the materials. When I formally began this project in 2007, I was frustrated by several aspects of the traditional approach to teaching astronomy. First and foremost was the textbook. I just don’t understand why astronomy textbooks, especially those used in introductory astronomy courses, must be updated so frequently when the updated content is far above the level of an introductory course. Knowing that a new black hole has been found isn’t equivalent to communicating any understanding about black holes any more than announcing the discovery of new exoplanets communicates any deeper understanding about them It is difficult for me to convey this to students who think they understand something just by hearing about it, so I have taken a rather hard line approach to avoiding this pitfall. I had become disappointed with every astronomy textbook I used because the content seemed watered down in every revision. I some cases, I contacted the author and was told that pressure to reduce content came from the publisher and they had to play ball. Nothing distinguished one textbook from another.

However, a bigger source of frustration was course content. My observation skills (I identified as an astronomer back then.) told me that my course, and indeed many similar introductory astronomy courses, don’t really live up to their marketing goals. They focus too much on shoveling content to students and then students regurgitating that content back on tests with no understanding. More seriously, the traditional approach gave inadequate, if any at all, treatment of the very foundational content that introductory liberal arts science courses are supposed to provide. I’m talking about among other things, you know, understanding the difference between science and belief systems, understanding testability and falsifiability, detecting faulty logic, discussing the roles of science and pseudoscience in contemporary American society, and carrying out simple investigations. These are more important than simply memorizing things that can be found in Wikipedia or by using a search engine. Still, there is more or less traditional astronomy content in the form of the geometry of the sky and correlating that with shadow behavior, understanding the periodic behavior of the most easily observed celestial bodies, and understanding gravitational attraction and its role in orbital motion. This meant discarding the majority of what is usually containd in a traditional introductory astronomy textbook and I have never looked back. I have years of course evaluations from students telling me how much they prefer the new approach to the traditional textbook approach. Eventually, I hope to be able to quantify that feedback in some way.

Anyway, I decided to leave the game and start using my own materials that I had been toying with. The course is organized around five broad topics (or chapters): critical thinking, observation, the celestial sphere, time, and gravitation. My semester has sixteen weeks, so that’s approximately three weeks per unit. However, I have always found that such attempts at pacing are highly artificial. I can’t control the rate at which students choose to engage in their own education; I can only try to do that. Therefore, I focus on deep understanding rather than breakneck pace as “covering material” because, well, that’s the way it should be.

Chapter 1 currently has six activities. They begin with an attempt at instilling the importance of collaboration (I have eight versions of this activity), and then move to science terminology, declarative vs. operative knowledge and operational definitions, detecting arguments and logical consistency, scientific frameworks, detecting logical fallacies and distraction techniques, and finally, scientific validity. I have tried to target each activity toward one of two very specific goals and accompanying standard on which students are assessed. Standards-based grading is employed. Woven into this first chapter is a thorough introduction to, and practice with, the elements of thought. Using them is a standard on which students are assessed.

Chapter 2 currently has six activities. The first five focus on observing a stick’s shadow from various places on Earth. Students are invited to look for patterns and draw conclusions about a shadow’s behavior. They have to get used to just getting the facts without trying to explain them. It’s difficult! Only two of the first five activities are required; the rest are optional. The sixth activity in this chapter invites students to use their shadow observations to work through Eratosthenes’ historical work on Earth’s shape, hopefully learning how to distinguish among various plausible scientific models in the process.

In chapter 3, the activities begin to resemble what students traditionally think of as astronomy. By this point in the course, they usually complain that they’re not “doing astronomy” when in fact, they are and just don’t understand that science doesn’t look like it does in traditional sanitized textbooks. Astute students will have understood this before this point, but most take a while longer to get there. In this series, students make simple nighttime observations to establish the main movements of celestial objects against the sky. They build a celestial sphere kit they purchased in lieu of a textbook and use it to relate a shadow’s behavior to Sun’s diurnal and annual motions. They see the same observations from a different point of view and hopefully can now connect sky observations to shadow behavior. They also model lunar phases in this chapter.

Chapter 4 is on time. If there is any astronomical topic that is relevant to everyone, it is the measurement of time. I currently have no activities in this chapter in a presentable form, but I hope to change that this fall. Students connect sky observations with the measurement of time as operationally defined by clocks. This builds up to a grea mystery, namely the mystery of why the dates or earliest sunrise, latest sunset, latest sunrise. and earliest sunset don’t coincide with the solstices. The answer lies in the analemma, and solving this mystery is the goal of this chapter.

My goal for chapter 5 is to understand the basics of orbital motion as a consequence of gravitational attraction. My approach is heavily influenced by Paul Hewitt’s approach in his conceptual physics text and I freely borrow from that source. If time permits, I take the opportunity in this chapter to lead students through the work of Galileo and Newton, again at about the level of Hewitt. In the past, I have even incorporated basic vector analysis in this chapter. Yes, vectors.

All of the completed LCTTA activities are available on the download page of my website. The latest versions will always be there. Last year, I figured out how to create PDF documents with editable text entry fields with LaTeX. I want students to quite literally create their own materials and having them type their responses directly into their activity documents helps get them there. They are asked to keep their activities with them and are free to revise their resonses as they go through the course. After all, scientists revise models all the time so why not ask students to do the same as their learning progresses? They get frustrated, though, because there are not necessarily definitive answers to every question. Unfortunately, they somsetimes bypass me with thier concerns and go over my head and I then have to, once again, explain everything to a host of administrators who claim to understand until the following semester when it happens all over again. Students are respoinsible for recording and tracking their own assessment progress. I secretly do it too, but I don’t tell them that. I want them to be invested in keeping up with their learning.

If you are interested in taking a shot at a very nontraditional way ot treating introductory astronomy, feel free to try these activities. All I ask is that you give me feedback on how well they worked or didn’t work. Most of the recent revisions have come directly from conscientious students who appreciate this approach. I also got valuable feedback from colleagues at AAPT meetings where I presented these activities as a workshop. Also feel free to post questions in the comments section below, but note that I won’t divulge answers to questions in the activities here for obvious reasons. Students are good at using search engines.



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