Category Archives: ASTRO 101

Capturing ASTRO 101 Students Attention with Naked-PPT

Tim Slater, CAPER Center for Astronomy & Physics Education Research,

Notwithstanding unexpected technical difficulties, I can remember the only time I’ve seen an astronomer intentionally teach for an hour without support from a writing board or a projector, computer, overhead transparency, or slide carousel; if you haven’t guessed it already, it was Harvard’s astronomy historian, the legendary Professor Owen Gingrich. So, we are taking it as an initial boundary condition that compassionate ASTRO 101 professors are going to use some visual support as a consistent strategy to get students information about your class.  I’m not advocating any particular commercial tool; however, so that I have a shorthand notation for the general concept of some projected visual, I’ll hereafter use the commonly recognized abbreviation for MS PowerPoint, PPT.

We already know that you definitely don’t want use PPTs that have too many words, too small of figures, distracting transitions and animations, or insufficiently contrasting colors.  You’ve endured too many of those yourself at professional science conferences.  But, the question at hand really is what about your PPT will help improve your course evaluations?  In other words, what will enhance students’ perception that you want to help students learn and that you follow an organized pathway?  Fortunately, purposefully designed PPTs can dramatically help here.

As a first step, let’s review the basic rules of what does and does not help on a PPT.  You might be thinking to yourself that you already know all of these things, but a quick tour through your building peaking in on other professors’ classes or wandering through scientific conference presentations should remind you that we can all forget the basics too often.

When faculty conduct surveys of what students do and don’t like about their professor’s PPT slides, they universally plea for professors to stop reading their PPTs to students.  Really.  Beyond that, consider the following:

Students DON’T like Students DO like
Too many words Short phrases to copy
Animated images Easy to read graphs
Unnecessary animations Slowly increasing  complexity of graphs
Inconsistent format Short video clips
Too many colors Consistent use of colored font for emphasis

Here is a place where a review of your materials from a confidential, critical friend can help.  A critical friend is the one-person you can depend on who will take time to quietly let you know when you have spinach stuck in your teeth or that you embarrassingly mistyped something in that ranting Department-wide email-memo you are about to send.  This person does not necessarily need to be at your institution, and perhaps it is better that they are not. But it needs to be someone you respect as an equal as well as a confidant. If you don’t have a critical friend, you need to start nurturing such a relationship so you have someone with which you can exchange your PPTs with to check for problems one of you might have missed.

The basic time-tested guidelines for PPT your critical-friend should check are:

  • No hard to see colors
  • No more than six lines of text
  • No more than six words per line
  • No complete sentences
  • No adjectives
  • No punctuation

The problem with projecting complete sentences is that students have been long conditioned to write down everything on the PPT, no matter how much you beg them to do otherwise.  This includes the capital letters starting the sentence, illustrative adjectives & adverbs, and punctuation at the end. We promise you that you do have the unexpectedly large amount of your limited each week available to allocate toward teaching your students how to effectively and efficiently take notes in addition to teaching astronomy.  You could staunchly maintain that college students should already know how to take notes and it isn’t your responsibility to teach them how, but then you’ll likely demonstrate to your students that you aren’t actually interested in helping them learn.  In other words, a wise professor wouldn’t unnecessarily provoke sleeping bear on this one, especially if the bear also completes end of course evaluations.

The notion of avoiding complete sentences on your PPT is part of the broader teaching strategy not overwhelming students.  You probably wouldn’t be surprised if we reminded you that learners cannot learn from a spouting fire hose of information drenching them with as many facts as possible.

Although the PPT-experts say you should avoid unnecessary pictures, we would argue otherwise. PPTs that only contain bullet points are as monotonous as some of those memorable professors you had in graduate school.  Pictures, even if gratuitous, serve to break up the boredom potential.  Regardless, you should always talk about the images you project.  Unlike you, novice astronomy students do not readily know what an image is or what is important about it.  Students also won’t have any sense of scale, even if a tiny legend is embossed across the bottom.   We’ll talk about where to find pictures for your PPT and how best to use them later in this chapter.  However, we need to talk about organized systems to get information to your students using PPT a bit more.

A perennial question among professors is whether or not to provide students with photocopies of your PPT, or if they should be provided online.  The first order argument for distributing them early is that students can allocate their scarce class time attention to annotating the PPTs rather than furiously taking complete notes of their own.  There are obvious advantages to this, not the least of which is ensuring you actually have your notes done more than 60-seconds before class starts. This also means that students who miss class or didn’t successfully copy down all of the PPT’s information have a back-up information system.

A contrasting perspective is that students won’t be motivated to come to class if the PPTs are available elsewhere.  We have to agree with the students on this one; if the only reason students have to come to class is to get information to memorize from the PPT, why go to class at all?  The numerous bloggings on this website are specifically designed to counteract this notion:  Your class time should be so well organized and carefully designed to be so incredibly valuable that your students wouldn’t imagine missing it in their wildest dreams.  If that’s not motivation enough to keep reading this book, we don’t know what would be!

If you do decide to distribute the PPT to students, we recommend that you strategically remove key information that students need to fill in.  Many professors find providing what we affectionately call Naked-PPT to be highly effective.  More formally known in the formal science teaching literature as “guided notes”, these are PPT with key information removed and replaced with a blank line for students to complete themselves.



PPT Displayed for Class PPT Given to Students
Definition of a Planet Definition of a Planet
1. orbits a star 1. orbits a _____
2. enough mass to become spherical 2. enough _____ to become spherical
3. dominant object in its orbit 3. dominant object in its _____


The underlying thinking here, confirmed by systematic education research, is that the process of students’ actively dressing the Naked-PPT during class will keep students more attentive.  Moreover, changing your PPT into Naked-PPT is takes just a few seconds.  First, complete and save your PPT presentation that you’ll be presenting in class.  Second, save your final presentation a second time with a new name, adding –Naked.ppt to the end of the name. In this Naked-PPT version remove one or two vital pieces of information from some of the slides. As a word of _______ here, don’t go overboard and remove too much information. You only need to add a few blank lines here and there to make strategy this work like a charm.  Removing too much information will make students perceive you are trying to trick them into coming to _______ by withholding information they need to succeed, which they will resent and report when they fill out your end-of-class _______ forms. Finally, distribute this Naked-PPT version to your students instead of the version you present during class.  It works with images too!

  Naked-PPT Slide

The process of creating fill-in-the-box images is surprisingly easy.  All we have done to create the example shown is insert rectangle shapes over some of the targeted words and filled them with white.

Another strategy engaging teachers use is to slowly increase the amount of information on their PPT.  Like the potentially provocative label Naked-PPT, in the old days professors would call this strategy by an equally lewd name, the ‘stripping transparency.’  The strategy then was to cover most of your projected information with an opaque piece of paper, and slowly reveal information as it was needed by the students.

Stripping Transparency - Naked PPT

The thinking in those days past, which is still applicable today, was that students would hurriedly write down everything on the screen before listening to anything the professor had to say and, in the process, miss the first half of the professor’s lecture.  This is because most students  can not listen and write at the same time, so the tactic was to limit what students had available to copy at any one time.  Today, the strategy is to use the Animate function in most PPT computer programs to slowly dispense information.  Adopting some version of this yourself is probably a wise choice for your presentations.


Definition of a Planet Definition of a Planet Definition of a Planet
1. orbits a star 1. orbits a star 1. orbits a star
2. enough mass to become spherical 2. enough mass to become spherical
3. dominant object in its orbit


Not only does this work well for bullet lists, but it also works well when teaching with images.

No matter how you use PPT, most professors find creating PPT to be an enormously time consuming task that effectively crowds out the more important aspects of teaching students to love astronomy.  This is especially true if you are a perfectionist.  The truth is that students don’t notice or appreciate whether or not your slides are perfect.  We recommend that you adopt the perspective that 80% good is good enough.  This isn’t so you have extra time to get to the golf course; instead, we want you to use all your available teaching-innovation energy to implement the interactive teaching strategies in the other pages on this blog.

You might be surprised to learn that nearly complete PPT sets already exist for your class.  Most book publishers have already paid someone to work really hard creating PPT sets for each chapter (they’ve also created test-item libraries, among other valuable resources).  Typically, these PPTs already use images from your selected book and have the most important vocabulary included.  If this isn’t enough, there are also PPT repositories online for all topics that are uncovered by Internet searches.  Moreover, you can even use PPT sets designed from other books. If you don’t know where to find these, call your book’s publisher and marketing representative who will enthusiastically share the many resources they’ve created.  By all measures, none of these PPTs you’ll find are close to perfect, nor are these tightly aligned to the specific teaching you want to do. These are, however, sufficiently good starting places to adapt to your own teaching, especially if you adopt“80% good is good enough so there is ample time to improve other parts of class” thinking.


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How to Make ASTRO 101 Classes More Memorable

Tim Slater,

At the end of the year, the perennial question ASTRO101 astronomy professors quietly ask themselves, “Well, what exactly did my students learn this year?” Yet, the answer of “what learning is occurring?” is often more elusive than one would hope. Perhaps surprising, one might think the question of what was learned is an easy intellectual pursuit. It seems only natural to assume that one could readily test students about their knowledge of a particular topic as they enter the class on the first day, and then again as they leave their final examination and subtract the difference to arrive at a quantitative measure. Although it sounds easy in theory, it turns out to be much more difficult in practice. As Michael Bennett, a previous Director of the Astronomical Society of the Pacific and DeAnza College professor likes to quip, “the only difference between theory and practice is that in theory, there is no difference.”

The first challenge is how to determine what to use as a fair pre- and post-test. Although some exist, like the Test Of Astronomy STandards–TOAST, these tests are notoriously difficult to create that actually measure what you want to measure. A second problem, even more challenging than the first, is that students don’t usually being enthusiastic to take a pre- and post-test and often require cajoling to participate. Although there are notable astronomy education researchers around who are very good at systematically managing confounding variables, sampling difficulties, and measurement validity issues, they rarely often allocate considerable intellectual energy to this particular version of querying learning.

We’ve known for decades that students fail to retain significant information when attending an hour-long college astronomy lecture. It’s not just today’s millennial students either, but was true even when we professors were college students years and years back. Few of us learned our astronomy by listening to a lecturer go on-and-on about the wonders of the universe, even when using Kodak slide carousel projectors. We didn’t learn much of it watching Carl Sagan on television either. Instead, for many of us, it was the outside of class work, pouring over the textbook, and talking with our peers and professor out of class, perhaps even long after sunset in the observatory, where we learned most of our astronomy. And, for the vast majority of us, we didn’t actually learn our juiciest astronomy until we began to formally teach astronomy in a classroom, share the night sky under the dome, or in the park talking with the public. The real learning of astronomy, as it turns out, is much more about social transmission than solitary book learning or listening.

Insights from the field of cognitive science provide tremendous insight into helping professors increase the amount of learning that can occur in ASTRO101. However, in order to leverage these insights, it helps to reframe our departure point from “What did students learn?” to the far less depressing and more action-oriented question of “What can I do to enhance what students remember about my ASTRO101 class?” In other words, my thesis is that informed ASTRO 101 professors can dramatically increase their success by focusing on memory, rather than on learning. As it turns out, memory is much more malleable than you might think.

From the perspective of the cognitive scientist, our human brain memory system is composed of two distinct components: working memory and long term memory. Working memory is the highly fragile and quickly fleeting notions and concepts that we keep in our head for a very short period of time before they are dismissed. Where did you last see your car keys? What was the name of the check-out clerk at the grocery store? How much was a gallon of milk when I was last at the store? What did I have for lunch yesterday? What was the name of the fifth brightest star in Aurigae. These are things we “know” only for a short-time. They are best characterized as things we don’t dwell on very much.

At any one time, human beings on average can manage only about seven things in their working memory. That’s how many digits are in a telephone number sans area code. That’s about how many variables you can monitor simultaneously when driving a car. You’ve probably noticed that if you’re driving in a rain storm, you usually can’t do extra things easily like talk on your cell phone that you can normally do in good weather. If you want to watch your working memory in action, multiply in your head two 2-digit numbers: 12 times 37. With some concentration, many of us can do it. But, instead, if I challenge you to multiply in your head two 3-digit numbers—123 times 456—most of us will quickly give up in frustration because that multiplication problem exceeds our working memory size, whereas the two 2-digit multiplication problem did not.

A critically important thing for upcoming master ASTRO 101 professors to become cognizant of is the nature of expertise. Experts are uniquely characterized by cognitive scientists as people who can collect and chunk information into packages to better squeeze more into their working memory. Novices, by definition, do not have the ability to chunk information into their working memory slots. As an example, consider when I say, “stars of Orion” to an experienced ASTRO 101 professor, that professor immediately loads as one single unit the location, shape, star colors, brightness, and star names into a single working memory slot occupying only a small 1/7-sized portion of their available working memory. A novice, on the other hand, fills all seven working memory slots with the seven brightest stars of Orion, and is unable to attend to colors or brightnesses let alone right ascension, declination, hour angle or even mythological origin of its name. This is a tremendous problem for ASTRO 101 professors, who can easily talk about Orion’s parts and compare it to other constellations or asterisms as well its altitude at different geographic latitudes when a novice is simply overwhelmed. The end implication here is that professional research astronomers are naturally inclined to label some astronomy education research-informed curriculum innovations as too simplistic for their students when in fact it instead presses the limits on students’ ability to comprehend. This is an intellectually precarious predicament. Our expertise gets in our way of understanding that we are fundamentally different than our students. My point is that there is a limit to how much information you can force feed students, and it is far less than most new astronomy professors initially think.

The other component of memory is long term memory. Long term memory permanently holds the names, numbers, images, cartoons, movies, and stories that are burned so deeply into our brains that we are loath to forget. You might recall things that happened to you decades ago— the birth of a child, advice an elder shared with you, or how you felt about the unique smell of a special place. These long term memories are also those things you’ve rehearsed time and time again—the names of stars, the sequence of moon phases, and the start-up sequence of your favorite dome. These are notions, both positive and negative, that you couldn’t forget if you tried.

Before you quickly jump to the natural question of how does one move things from short-term working memory into long-term permanent storage memory, let’s consider how these two things are different. Working memory is characterized by information flowing into it and then rapidly flowing out of it when the brain perceives it is no longer needed. This is partially to explain why we have few memories of the first years of our life—we simply don’t need the information cluttering up the mental works. (It is quite probably related to our infant-selves not yet having a sufficiently developed language to describe and encode those experiences into long term memory, but that’s a different article.) It also explains why we are able to completely ignore than thousands of individual pieces of irrelevant information that enter our sensory system when driving, and only pay attention to the most relevant. Here is the rub: For many students, decontextualized factual information delivered rapidly in the lecture hall often easily flows in and out of working memory without sticking around long enough to be stored in long term memory. The key to getting things to soak around in the working memory area of the brain long enough to at least have a chance of getting stored into long term memory is that the audience must have sufficient time to think about it, to mull it over, to see how it relates to other thoughts, previous experiences, and emotions, all without being distracted by new information or images that crowd their way into limited working memory. What cognitive scientists tell us is that memory is the residue of thought.

Perhaps surprising, we’ve long known how to get ideas to stick inside people’s heads long enough for them to think about it deeply enough to produce memories. This seemingly simple keystone is through the long-held tradition of telling stories. Allow me to advance a seemingly unrelated but perhaps powerful example that has been widely used elsewhere: Consider as a person living in Western civilization, you are probably aware of a widespread book generally known as the Bible. You don’t need to be a spiritual person or brought up in a strictly following Jewish or Christian family to have heard of this book and know some of its important contents. Simply living in a westernized society is enough to consider this example. Here is your task: List the Ten Commandments the Lord gave his followers. Grab a piece of paper and make alist.

  • Yes, list all of them.
  • Yes, there are ten.
  • Yes, one is about murder, and another about adultery.
  • Keep going.
  • Don’t worry, take your time ….

Ok, by now you’ve probably grabbed your cell phone or computer or even a Bible and looked them up. How did you do? Unless you have developed a mnemonic device, most people reading this probably struggled with getting all ten, or perhaps, even half. Don’t worry if you didn’t get them all, this is common even among people who identify themselves as regularly attentive Bible students.

Instead, consider the answers to these questions: What happened to Adam in the Garden of Eden? What happened to his son Abel? How long did Noah spend in the Ark? How did Jonah try to hide from his omnipotent god? How many following disciples did Jesus have? (And, for bonus points: Where were the Ten Commandments handed down and to whom?) My experience seeing many people take this informal quiz is that people growing up in Western cultures generally remember most of these things. This seems to present a contradiction: How is it that people cannot readily remember 10 simple rules of life listed in the Bible even when raised in deeply religious homes whereas most people of widely varying faiths and experiences can often readily answer these and an surprisingly wide array of questions about perhaps not so important details about religious doctrine to which they sometimes rarely pay any attention to? The answer is again, stories. We most easily carry information within ourselves through stories, and have throughout much of history.

Humans are innately able to internalize details within stories much more efficiently than even the most eloquently presented facts. This is because stories contain elements that force the listener to engage in thinking, and this thinking results in storage in long term memory. The underlying mechanism is that if you have to think a lot about a notion, your brain decides that it must be important and stores it for later recall. Alternatively, if you don’t attend to an idea for very long, then your brain decides it probably isn’t very important to come back to it, and discards the briefly considered notion.

What are the elements of a story that cause one to ponder it long enough to remember it? First, stories usually follow a logical sequence of events—a sequence is easier to follow than randomly disconnected facts. Second, stories are characterized by cause and effect. Characters do things and there are consequences to those actions. Sometimes a listener agrees with the actions, and other times a listener disagrees with decision a character makes. This is important, albeit narcissistic—an engaged listener must decide if he or she would do the same thing in a given situation or not. Moreover, stories can’t possible relate all of the precise facts that an observer would see, so the active listener must make inferences. What’s fascinating here is that these emotional connections to the story sequence, the characters questionable actions, and inferences from the left out details that combine to make one’s brain decide to commit the story to long term memory. The bottom line is that engaging in a story requires active thinking, which is why stories are better remembered than rapid firing of precisely articulated and cleverly illustrated facts that leave no room for students’ interpretations.

Although the idea that it is what is left unsaid in a story that makes it more memorable can be a bit unsettling initially, it does hold up to examination. Imagine for a minute a series of powerful images you might have recently shown an audience: Hubble Ultra Deep Field, Martian Surface Water, Pluto’s IAU Vote, or TMT atop Maunakea. Its only natural to tell students about the images. What if, on the other hand, the images were used in conjunction with questions, rather than the facts? In the spirit of being provocative, consider alternative captions in the below:


IMAGE: Hubble Ultra Deep Field
-This picture shows more than 10,000 galaxies in a tiny region of space vs  Do astronomers compete against one another for highly limited telescope time?

IMAGE: Mars Phoenix Lander discovering water
-Water observed on Mars vs  How could a Faster-Better- Cheaper Mars Phoenix Lander, created from spare parts, find water beneath rockets?

IMAGE: 2006 IAU Vote on Pluto
-Pluto is now classified as a dwarf planet vs  Pluto is still there; but, why can’t smart humans agree on its category?

IMAGE: Artist’s Conception of Thirty Meter Telescope on Maunakea
-is being built in Hawai’i vs  Where should the next great new telescope be built?

My thesis here could naturally be misinterpreted as suggesting that facts are unimportant or that students don’t really care about hearing cool facts. In stark contrast, I am convinced that students really do want to hear about what’s it called, how big is it, how far away, and how did it get that way? What I am advocating here is that although precisely articulated and cleverly articulated facts are definitely cool, they are insufficient on their own to deeply engage the audience in a memorable experience. Given that memories are the residue of thinking, it behooves the compassionate ASTRO 101 professor to be sure that the students has the opportunity to ponder questions, make inferences, and be positioned to welcome the facts and figures available to them when they’re primed and ready. The implication from cognitive science is that astronomy lectures should be filled with ponderous questions and connected stories that the students can hang on to during each class. Taken together, all of this means that with purposeful effort, ASTRO 101 classrooms can be uniquely created to make meaningful and memorable connections between students and the cosmos.

Bibliography for Further Reading (Check Out the CAPER Team Amazon Book Store):

  • Ambrose, S. A., Bridges, M. W., DiPietro, M., Lovett, M. C., & Norman, M. K. (2010). How learning works: Seven research-based principles for smart teaching. John Wiley & Sons.
  • Bransford, J. D., Brown, A. L., & Cocking, R. R. (1999). How people learn: Brain, mind, experience, and school. National Academy Press.
  • Levitt, S. D. (2014). Think like a freak: The authors of freakonomics offer to retrain your brain. Simon and Schuster.
  • Slater, S. J., Slater, T. F., & Bailey, J. M. (2010). Discipline-Based Education Research: A Scientist’s Guide. WH Freeman.
  • Willingham, D. T. (2009). Why don’t students like school: A cognitive scientist answers questions about how the mind works and what it means for the classroom. John Wiley & Sons.

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Should I Teach ASTRO101 With Metric Units or US-Standard Imperial Units?

Tim Slater, Senior Scientist, CAPER Center for Astronomy & Physics Education Research,;

A long-standing debate in the teaching of astronomy at the college level—and science in general—is whether to teach using metric SI units or customary US-standard units.  At first glance the argument seems to be based on two juxtaposed positions.  On one hand, US college students are largely unaware of the metric system and therefore need to be provided values for distance in more familiar units.  On the other hand, real science is actually done in metric units and students studying in a science class should use the language conventions of science.  It is this second position—authentic science uses metric units—that most college science faculty adopt.  A cursory survey of most astronomy textbooks reveals that most distance values are given in metric units (with US-standard units often provided parenthetically) in the narrative sections, with data tables using metric units most frequently. Upon further reflection (or perhaps being urged to think more deeply from a learning and cognitive science perspective), one wonders if there is a more nuanced situation here and a more thoughtful approach is warranted?  Cognitive science provides at least two boundary conditions to be considered in a more nuanced version of this debate: (i) issues related to novice-vs-expert learning and (ii) issues of cognitive overload.

To take a step back, we should acknowledge that the question of which system of units to teach under has been a raging debate for decades (1, 2, 3) . The United States’ historical efforts to go-metric have been a complete failure and are relatively well-known.  I don’t have space here—in any unit system—to delve deeply into our metrification attempts, such as unfruitful efforts to change all US highway road signs to metric, which I believe only still exist south of Tucson). For the passionately interested reader, Phelps (4) has written about much of that history.

In recent years, however, education researchers have taken up the task of studying how learners conceptualize size and scale with the explicit goal of helping teachers teach better and helping students learn more.  Much of this education research work was funded under the banner of rapidly advancing nanotechnology because educators needed to figure out how to help students learn about this new technology.  Their work extends to astronomy educators because what NC State’s Gail Jones and her collaborators learned was that many students, nor K-12 teachers, fail to accurately conceptualize many distance values at all, big or small. (5-7) This is alarming because much of teaching and learning in astronomy is about “how big and how far.” (8)

Some professors have found it fruitful to use videos to help teach relative scales, using videos like Powers of Ten. (9- 11)  Perhaps narcissistically, Jones and Tretter’s ongoing research suggests that this video works so effectively because the video starts with what people are most familiar with – the size of a human body.

Most people understand sizes and scales based on benchmark landmarks and mental reference points from their experiences. K-12 students tend to think of the world in terms of objects that are: small, person-sized, room-sized, field-sized and big.  High school and college students also sometimes include shopping mall-sized and college campus-sized objects in their listings.  Further, people’s out of school experiences involving measurement of movement have the greatest impacts on their sense of size and scale—walking, biking, car travel—as opposed to school experiences where they have rote memorized numbers from tables. Consistently, it is to these common experience anchors that people use various measurement scales.

For us teaching astronomy, this is where the cognitive science issue of novice-vs-expert rears its ugly head (13).  Compared to a novice, an expert uses their experiences to automatically and often unawareingly change between scales.  For example, when measuring the distance between Earth and Neptune, would one describe it in meters, astronomical units, or light-travel-time?  The answer is, of course, it depends on why an astronomer would want to know such a distance.  For an expert, using meters, AU, and ly is readily interchangeable whereas for a novice, these are three totally separate determinations.  When I ask my students how far it is from where they are sitting to the front entrance of the building, or to the city with the state capital, they can usually give me a reasonably close answer using units of their OWN choosing, often it is time in minutes or hours, or in distances like American football field-yards or miles.  If I specify the units their answers must be in, such as feet or kilometers, my college students generally have no idea.  Experts are fundamentally different than students.  We readily move between parsecs and light-years, whereas our novice students cannot—no matter how much we wish they could.  As it turns out, if students could easily move between measurement systems, they wouldn’t be novices, they’d be experts and we teachers might be out of a job.  In other words, we can’t simply tell students that a meter is about a yard, and two miles is about 3 kilometers and be done with it—if it was that easy, we’d have done that already and there would be no ongoing debate.

One might naturally think that astronomy students should be able to easily memorize a few benchmark sizes (e.g., Earth’s diameter is 12, 742 km and an astronomical unit is 1.4960 E 8 kilometers) and then they could handle almost anything by subdividing or multiplying.  The problem is that the characteristic of an expert, as compared to a novice, is that experts chunk ideas more easily, allowing experts to make quick estimates.  Novices have no strategies to be able to do this.  Moreover, Hogan and Brezinski (14) aggressively argue that an individuals’ own spatial visualization skill level is the most important component in measurement and estimation by portioning and estimating distances.  Unfortunately, these do not appear to be directly related to one’s calculation skills and teaching students to convert between units using dimensional analysis heuristics is mostly fruitless.  The bottom line here is that students rarely enter the classroom with well-developed sense of scales going beyond their human-body size and experience with movement from one place to another.  The cognitive science-based perspective of a novice-verses-experts teaching problem is well-poised to interfere with any instruction where students are being given sizes and scales in units with which they are highly unfamiliar.

As if this weren’t challenging enough, there is also the cognitive science-based problem of cognitive load.  Cognitive load is the notion that students only have so much working mental capacity at any one time available to apply to learning new ideas. (15).  That means when a professor says a comet is 10,000-m across, the Sun’s diameter is 1.4 million-km, the Virgo cluster is 16.5 Mpc, and a quasar is at a “z of 7”, students either have to stop being active listeners to your lecture for 30-seconds and figure out what those units mean and miss what you really wanted them to know, or they have to ignore any referenced numbers all together so that they can keep paying attention.  The teaching challenge here is that I suspect the most important thing you want students to take away from a lecture about a quasar at a z of 7 isn’t precisely how far away it is, but instead what it tells you about the nature of the universe.  The risk here is that introducing numbers and unfamiliar units gets in the way of the ideas you are most likely trying to teach.

The research alluded to earlier points to using relative sizes as being more fruitful for helping students learn than absolute, numerical sizes.  I try to rely on things they are most familiar with and then help them to use simple, whole number ratios.  For example, North America is about three Texas’ wide, the Moon is about one North America, Earth is about four Moon’s, Betelgeuse is 1,000 times larger than the Sun, and …. Notice I don’t have to say very many of these ratios before you starts skimming to the end of this paragraph yourself : That’s the same experience your students too often have. Fortunately, many modern astronomy textbooks now give planet sizes in Earth-radii, just like we have long given solar system distances in astronomical-unit Earth-orbit sizes (17).  I think this is a really good starting place. After all, five years from now when you run into an alumni student, do you really want the one thing that they most remember about your class to be the distance to the Crab Nebula in parsecs?

As astronomy teachers focused on student learning, we seem to be left no longer with the seemingly simple question of “should I teach with metric or US-standard?”, but with the more robust question of “do I seriously take on the semester-long task of teaching scales and measurement or do I teach using ratios using familiar distances, which vary widely from student to student in my diverse classroom?”  Re-framing the question this way is much more actionable and diminishes the less productive “science versus the rest of the world” notion.  I contend that this new either-or question is much more worthy of research and debate.

Personally, I have a lot of astronomical ideas with which I want my students to engage.  My personal belief is that I’d rather students deeply engage in physical processes and causality of astronomy, stimulated by wonder and curiosity.  I further want them to engage in how astronomy is deeply entrenched in society and technology.  To do this, I choose to give up on allocating the time necessary to fully teach the metric system and focus my efforts on teaching things in terms of relative sizes and avoid using a self-defeating calculator-task whenever possible (16).   Experienced mathematics teachers will tell you that you can’t really teach the metric system with a single 15-minute lecture to novices: Teaching the metric system takes a commitment throughout the entire course.  The notion that metric is easy because it is all base-10 is nonsense when it comes to teaching astronomy, despite my desire for it to be otherwise. The bottom line is that I decided that I want to teach astronomy rather than teach the metric system, and I don’t have time to teach both well.

My textbook writing solution (17) is that I provide sizes in both metric and US-standard units where it makes sense.  Against the common convention, we have made the agonizing choice to include the US-standard units first (with the metric units parenthetically) so as not to unnecessarily put off neither the students who find US-standard units to be less off putting, nor the vast majority of professors who desire their science course to be characterized by the metric units characteristic of science. My eventual, downstream goal is to provide size and scale referents for as many common anchor objects as possible without overloading the students, and focus on allocating serious class-time to teaching the sizes of a few core anchor-sized objects.  These anchor objects include sizes of Earth, Sun, Earth’s orbit, average distance between stars, Milky Way diameter, distance to Andromeda, and light-year, to name a few.  Fortunately, teaching the distance of a light-year is not either a metric unit or a US-standard unit, and is thus elevated above the present debate no matter what your perspective.


  1. Helgren, F. J. (1973). Schools are going metric. The Arithmetic Teacher, 265-267.
  2. Vervoort, G. (1973). Inching our way towards the metric system. The Arithmetic Teacher, 275-279.
  3. Suydam, M. N. (1974). Metric Education. Prospectus. URL:
  4. Phelps, R. P. (1996). Education system benefits of US metric conversion. Evaluation Review, 20(1), 84-118.
  5. Jones, M. G., Gardner, G. E., Taylor, A. R., Forrester, J. H., & Andre, T. (2012). Students’ accuracy of measurement estimation: Context, units, and logical thinking. School Science and Mathematics112(3), 171-178.
  6. Tretter, T. R., Jones, M. G., Andre, T., Negishi, A., & Minogue, J. (2006). Conceptual boundaries and distances: Students’ and experts’ concepts of the scale of scientific phenomena. Journal of research in science teaching43(3), 282-319.
  7. Jones, M. G., Tretter, T., Taylor, A., & Oppewal, T. (2008). Experienced and novice teachers’ concepts of spatial scale. International Journal of Science Education30(3), 409-429.
  8. Slater, T., Adams, J. P., Brissenden, G., & Duncan, D. (2001). What topics are taught in introductory astronomy courses?. The Physics Teacher,39(1), 52-55.
  9. Eames, C., Peck, G., Eames, R., Demetrios, E., & Mills, S. (1977). Powers of ten. Pyramid Film & Video, available on YouTube at:
  10. Cox, D. J. (1996, January). Cosmic voyage: Scientific visualization for IMAX film. InACM SIGGRAPH 96 Visual Proceedings: The art and interdisciplinary programs of SIGGRAPH’96(p. 129). ACM.  The IMAX Cosmic Voyage Video, narrated by Morgan Freeman, available on YouTube at:
  11. Jones, M. G., Taylor, A., Minogue, J., Broadwell, B., Wiebe, E., & Carter, G. (2007). Understanding scale: Powers of ten. Journal of Science Education and Technology16(2), 191-202.
  12. M.G. Jones (2013). Conceptualizing size and scale. In Quantitative reasoning in mathematics and science education: Papers from an International STEM Research Symposium WISDOMe Monograph (Vol. 3).  Available online at:
  13. Bransford, J. D., Brown, A. L., & Cocking, R. R. (1999).How people learn: Brain, mind, experience, and school. National Academy Press. Available online at:
  14. Hogan, T. P., & Brezinski, K. L. (2003). Quantitative estimation: One, two, or three abilities?.Mathematical Thinking and Learning5(4), 259-280.
  15. Sweller, J. (1994). Cognitive load theory, learning difficulty, and instructional design.Learning and instruction4(4), 295-312.
  16. Slater, T., & Adams, J. (2002). Mathematical reasoning over arithmetic in introductory astronomy.The Physics Teacher40(5), 268-271.
  17. Slater, T. F., & Freedman, R. (2014). Investigating astronomy: a conceptual view of the universe. Macmillan-WH Freeman Higher Education. (available in the CAPER Team Book Store)

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Can Your Syllabus Improve Student Motivation?

Stephanie J. Slater, CAPER Center for Astronomy & Physics Education Research, 

It seems reasonable to assume that students with high motivation have a better chance to do well in your courses than students who are unmotivated—or worse, negatively motivated. This begs the question of how we might enhance our students’ motivation.

Before we get to this, we should consider whether or not it is our responsibility as professors to even acknowledge student motivation at all. By this I mean, isn’t it sufficient that students pay their tuition to come and sit in our classes, and shouldn’t this be motivation enough all on its own? I don’t have a solid answer to this, but what I do know is that over the years, I’ve changed my philosophical perspective that it is my job to help students learn how to learn rather than cleverly download facts into their brains. The truth is that five years from now, I want them to think astronomy is “cool” more than I want them to know the numerical diameter of Saturn. That means that the astronomy class needs to be a transformative experience for them—which isn’t the same thing as just having a great time. Its about them being different as a human being because they’ve taken astronomy, and I want that different to be a positive transformation, rather than a negative one. Taken together, I think it is important that we pay attention to enhancing our students’ motivation, if for no other reason than to not engender negative motivation about learning astronomy.

Stephanie Slater discusses motivation theory at MIT

Perhaps surprisingly, your course syllabus is the most tangible means by which you can quickly establish a positive “course climate.” This is important because, if you’ve read your faculty evaluation forms from previous semesters, you might have noticed that there are usually several items that specifically attend to the nature of the “course climate” or “classroom environment” you established. For instance:

  • “The instructor established and maintained a respectful and welcoming learning environment from the first day of class”
  • “The instructor adapted teaching methods and materials to address my individual learning style and abilities”
  • “The instructor´s direction in this course is free from attitudes/actions demeaning to women and minorities.”
  • “This instructor seems aware of my needs, abilities, and interests.”

These are not items on which you desire a low score, yet I suspect, that these are the items that angry students will use to tank you at the end of the term. So what  about getting good marks here, and as a side note, actually creating a better classroom climate?

One framework of classroom environments characterizes classrooms along a continuous spectrum that looks something like this:

<—explicitly marginalizing—implicitly marginalizing—implicitly centralizing—explicitly centralizing—>

As you might guess, you do not want to be on the far left side of this spectrum if you want to have positive teaching evaluations.

Unfortunately, most courses are characterized as “implicitly marginalizing.” An implicitly marginalizing class is one that “excludes certain groups of people, but in subtle and indirect ways.” To put this to use, the modern version of “certain groups of people” is no longer women and minorities. It’s now non-traditional students:

  • students who go to school part time and work part or full time
  • students with children at home, minority and immigrant students who are culturally bound to be caretakers for their larger family group
  • English language learners, etc.

This is true for both high school and college settings.

To be conservative, we should probably all assume “implicitly marginalizing” to be our current status, and we should all be looking for ways to move to the right side of the spectrum. If you are already to the right side of the spectrum, this perspective won’t hurt you. Erring in the other direction will.

So, what does classroom environment have to do with cell phones, laptops and your end-of-term scores? There are two pieces here. The first is “motivation,” and the second has to do with “tone.”

MOTIVATION: We sometimes think that “motivation” is a pretty vague thing, but there are people who have thought a lot about it and have broken it down into something that you can chew on. One way to think about student motivation is that it is a mixture of three things:

A. Motivation is about “Value”: Does this class help me meet my goals? Which may be related to intrinsic value of education and the material, but it’s probably not. It has more to do with meeting my social goals, my career goals, etc.

Perhaps the fastest way to reduce the “value” a student sees in your class, is to put your class in conflict with things that the student values more. Like their job, their kids or their family. If I need my cell phone to stay in touch with my child’s caregiver, and you tell me I can’t have my cell phone out to text that caregiver, you have now put us into conflict.

Does this mean that students will sometimes multitask? Yes. And that’s not great. But it would be far worse to set up a system in which we are at odds, and I’m constantly worried about my other obligations. Because if you make me stressed out and anxious about these other things, my amygdala fires and shuts down my hippocampus, and I can neither access nor store memories..,But the neurobiology thing is a whole other thing.

To keep it simple, the syllabus can either show the students a pathway by which they can meet their most cherished goals, or it can show them that the two are in conflict. Conflict = bad evaluations.

B. Motivation is about “self-efficacy.” Can I do this thing that I have to do for this class?

Can we think of ways in which students might use devices like cell phones and laptops, in order to help them get through the class. Yep. Do you want to be the instructor who tries to control student behavior by removing laptops, and inadvertently removes an important educational tool for some students. Nobody does, but we often focus on control so much that we forget to think about whether or not we’re hindering someone unnecessarily.

C. Motivation is about “Perceiving a Supportive Environment”. Does the student perceive that the instructor is creating an environment that will help them be successful, or does the student think things like:

  • “This instructor does not understand my commitment to my family,”
  • “This instructor does not understand that I have to be able to text my boss if I want to keep my job—-this instructor only wants to teach the rich who can afford to go to school full time.”
  • “This instructor doesn’t want me to succeed because she says that I can’t come into class 5 minutes late…but sometimes the bus is late getting me to campus….”

So the question is, for the non-traditional student, does your syllabus increase their sense of value in your class, make them believe that they can use tools to succeed, and does it make them believe that you are supporting them in the difficult task of juggling their education and their other commitments?

It’s funny to think that something so small as a cell phone/laptop or late admittance policy can have such big whammy on student motivation, but it can clearly hit all three pieces of student motivation if handled badly. The research, shows it to be true: replicated, over decades of studies on students in many different types of courses.

BUT, you might say, what can I do to reduce the non-necessary use of cell phones and the off-task use of laptops? Can I put anything in my syllabus? This brings us to:

TONE: Ishiyama and Hartlaub (2002) studied how the tone of a syllabus affects course climate. They found that “students are less likely to seek help from an instructor who worded policies in punitive language.” Given that “instructor accessibility” is an important factor on course evaluations, you don’t want students feeling that way. Sure you have office hours, but if they don’t feel like they can approach you, it doesn’t matter: you are perceived to be unapproachable. In other words, the specific tone (intentional or unconscious) can significantly bring down your instructor accessibility score.

Interestingly enough, instructors could state the exact same policy, but do so in rewarding language, and get a completely different response. In 1985, Rubin described instructors who put policies in boldface block letters, or who promised harsh punishments as “scolders.” Students don’t like scolders. Going back to what was said earlier about motivation, a “scolder” is not perceived to provide a supportive environment. Scolder = low evaluations.

–> PLEASE BE ON TIME     vs      Please, be on time.

So if you have to have some policy in your syllabus about lateness, phones, laptops, tablets, or whatever the current “control fetish” might be, don’t put it in bold face. Don’t pronounce sever punishments. Don’t create punishments that embarrass students. In other words, don’t act like a Big Bad Guy.

Because, the research has verified that students don’t like instructors who create policies that are counterproductive to their motivation, and who state those policies in a dictatorial manner.

A great book to read on all of this is the Ambrose et. al. book: “How Learning Works: Seven Research-Based Principles for Smart Teaching.” It’s extremely useful, and contains references for all of the research that has gone into everything that I’ve repackaged here.

This means that a professor who is serious about improving their course learning environment will ask themselves some hard questions, including:

— >  What policies do I enact that might make students feel demeaned, disenfranchised, or disabled from meeting their out-of-class commitments?

— >  How can I change the wording on just one thing in my syllabus, to make it seem more hospitable for my students?

Perhaps some specific examples will help. Over the years of helping professors improve their teaching evaluations, we’ve discovered some pretty “inhospitable” syllabi.

Here are some examples definitely worth considering changing:


  • OLD: You must have a scientific calculator for this class that can handle exponential notation.
  • POSSIBLE NEW WORDING: Although not required every day, a calculator will sometimes be helpful in completing the homework for this class. Any inexpensive one will do just fine, as long as it is labeled “scientific” and one can be purchased for about $12.


  • OLD: Class attendance is REQUIRED!! Class attendance will be record five times throughout the semester – unannounced – and attendance is worth 10% of your grade.
  • POSSIBLE NEW WORDING: Students who regularly attend class almost always earn better grades and learn more astronomy than students who miss class. Although sometimes missing a class is unavoidable, our class time is specifically designed around collaborative group learning activities that will help you score better on exams. Although you can sometimes do these assignments on your own, talking through these ideas with another student and with the support of your professor will enhance your learning and your grade. Occasionally, these learning tasks will be collected and participation points will be awarded to add to your grade.


  • OLD: Office hours will not be held within 24 hours of the exam.
  • POSSIBLE NEW WORDING: I will hold extra office hours during the week leading up to the exam and hold an open question-and-answer session at 4pm two days before the exam–bring snacks to share with classmates!


  • OLD: Class time is important and will always start on time. Do not be late or leave early.
  • POSSIBLE NEW WORDING: I promise to start and end class on time. I would appreciate it if you did too.

Positive course learning environments can help keep students motivation high in your astronomy class, whereas negative environments too often lead to student failure and dissatisfaction on everyone’s part. Motivation might seem like a difficult nut to crack, but as a first step, we suggest taking a look at your syllabus, or have a critical friend look at your syllabus. You might find that this first step opens up all sorts of doors to improving student motivation and nurturing a more positive class climate.


Filed under ASTRO 101

How to Use Video Most Effectively in #ASTRO101

Tim Slater, CAPER Center for Astronomy & Physics Education Research,

NoProbably notI seriously doubt itIt’s just not a good idea. and I’m dubious.  These are the most common responses all consulted teaching experts give when queried by colleagues about whether or not they should show videos in their introductory astronomy survey class. Sounds pretty negative doesn’t it?  This negative reaction is the direct result of seeing professor after professor misuse and abuse otherwise perfectly good videos during class.

It’s not that there aren’t great video resources out there: there really are amazing video resources available in astronomy, perhaps more than any other field (other than oceanography).  The number of high production astronomy videos made in the last decade is nothing short of astronomical. Satellite television providers such as the Discovery Channel, History Channel, NASA TV and Science TV have joined the longstanding and highly respected video production efforts of IMAX, PBS, and the National Geographic Society NatGEO TV—just to name a few of the many talented production efforts out there—to super high-production quality videos and video series.

For one, the most highly rated of these videos show the best “talking head” profiles of some of the most influential and photogenic astronomers around.  Neil deGrasse Tyson has thousands of social media followers and has even appeared repeatedly on television talk shows like Comedy Channel’s Daily Show with Jon Stewart and the Steven Cobert’s Cobert Report, as well as popular late night television talk shows. These videos go a long way to helping viewers see that astronomy is a human enterprise.  Moreover, many of these videos do a reasonably good job of showing today’s astronomers as being highly diverse in racial demographic and quite a few women.  The good news here is that television can play a role in helping expand and enhance the stereotypical image of an astronomer from being only a white-haired (or non-haired) white male smoking a pipe in a cold, mountain-top observatory to a more contemporary view of astronomers as being equally likely to being a partying group young males and females from across the racial spectrum.  As evidence, I submit to you that the NASA JPL video clips showing young astronomers dancing, yelling, and celebrating during successful Mars landings are enormously popular on video websites like YouTubeSome of these individuals even acquire a tremendous social media following that greatly extends their previously allotted 15 minutes of fame.  In other words, these videos can serve to enhance the image of astronomers as people, and perhaps even improve the nation’s evaporating science, technology, engineering and mathematics (STEM) career pipeline.

Perhaps more important than showing astronomers as being a diverse group of people, these videos include the latest and greatest graphics-intensive animations and computer simulations.  There are only three words to describe these animations—and all three of them are “WOW.”  Many of these animations have a wow-factor that make even the most curmudgeonly critical astronomers look up from their computers and pause to watch.  Over the last decade, the entire career field of scientific visualization has stood up to take advantage of and match new computer graphics capabilities with the high-computing power that was once restricted to supercomputers and is now found waiting inside desktop machines.  NASA Goddard Space Flight Center’s Scientific Visualization Studio, as but one example, has hundreds of videos ready for Internet download that can be used equally well in television documentaries as well as in astronomy classrooms.  In other words, the resources are there and ready to go, so why don’t we just turn them on and let them run for the entire class session?  Or even better, if students can watch these amazing videos in the evenings while wearing their bunny slippers, then there doesn’t seem to be any need for students or faculty to go through the hassle of fighting for a parking place and coming to campus at all!

Taken together, the current situation seems to be that we have engaging and good looking speakers describing super high-quality animations just a mouse click away. This entire notion of using videos IN class—or using videos FOR class altogether—sounds like a no brainer, WIN-WIN situation for everyone. This is especially true when you remember that too many astronomy professors are simply terrible lecturers to begin with.  (Personal Note: I have been driven to the edge of complete despair watching professors read a textbook to their students in an endless monotone flux too many times to count.) You might be inclined to say, “hey, what are we waiting for? Bring on the videos?

But, as it seems with every “force” in the universe, there are unfortunate dark sides of using even the highest quality and most scientifically accurate videos in your astronomy class.  One has to do with the innate—and perhaps immutable—nature of students.  Will students pay attention to a video better than a live lecture? Faculty probably wonder, even if only as an mere idle curiosity, how many of their students are really paying attention to their lecture as the hour wears on. The answer is, not many. We often hear colleagues say, “ah, today’s students just can’t seem to pay attention like they used to.”  Of course, those same colleagues are really talking about themselves!  Nearly forty years ago, researchers discovered that the worst fears of college lecturers are in fact true: Verner and Dickinson (1967) observed lectures and found that only 66% of students showed the slightest signs of attention to lectures after 18 minutes, compared to the beginning of the lecture.  And, worse yet, essentially no students they observed showed signs that they were completely attentive after 35 minutes.  That’s not a good omen.

In the end, students are not likely to watch a video with any more interest than they are to watch a lecture.  Research backs too backs up this supposition.  Fascinating research by Alison Gopnik, author of the famed book Scientist in the Crib, and Patricia Kuhl, studying the development of language, reports in recent research that infants do not learn from video of their mother with nearly the same attention that they will when mom is physically present.

The more argumentative reader might pose that students are able to watch Hollywood movies for hours on end with rapt attention, remembering some of the most obscure details.  Again, research helps us understand what is going on.  Daniel Willingham proposes in his book, Why Don’t Students Like School, that video material being presented needs to at least have the potential to make an emotional connection with the listener in order to be deeply remembered.  Hollywood movies and adventure television shows do this in spades: the damsel in distress ready to be rescued, the seemingly impossible to solve mystery, the hero’s journey from adversity to triumph.  One would be greatly surprised if even the most accurate of black hole animations stands well-poised to make an emotional connection for many students—geez, animations generally only seem to barely generate recognizable emotions within professors themselves when videos have glaring mistakes that provoke a professors’ ilk (Do I need to remind you about the Disney movie, “The Black Hole”?).

The other component of a dark side of using videos has to do with the innate nature of professors.  By and large, professors seem to be insanely busy people—if you aren’t sure this is true, all you need to do is ask a few and they will be happy to tell you how busy they are. Many professors travel frequently and need to miss class.  Because professors are people, when a professor has to miss a class or don’t have time to prepare for class, one seemingly easily implementable solution is to show their class a video.  As a substitute for a well-planned lecture, rather than no lecture at all, a video might initially seem like a reasonable option.  As pointed out earlier, modern videos have fantastic animations, good looking and well-spoken experts, and sometimes engaging story lines.  But the reason we have professors who are experts in the field teach classes is not that they are great speakers—if we only needed great speakers we’d hire actors to teach our classes—rather, we hire experts because they should be able to coach students along the pathway of learning astronomy.  When a professor understands the material, they are able to probe students understanding by posing examples and counter examples of different concepts to help students extend their understanding.  Moreover, they are able to provide rapid feedback to students who are struggling to learn astronomy in ways that performing actors just can’t do.  In other words, it’s the two-way human interaction that is needed, not the attractive downloading of information, which constitutes effective astronomy teaching.

Fortunately, there are some effective strategies to take full advantage of high-quality video resources. One is to use only short video clips of about 3 minutes (5 minutes as an absolute maximum).  The key is to have a very specific reason for using the video clip and to fully inform students what they are about to see, why you are showing it to them, and what they are supposed to take away: this is precisely the same tried-and-true presentation skills from physics education research about how to do effective classroom demonstrations.  When Thornton and Sokoloff researched interactive lecture demonstrations (ILDs) in teaching physics, they found that what a professor does BEFORE they do a demonstration was much more influential than anything that a professor did after the demonstration.  So, that is going to be true with videos too.  In fact, one sure-fire strategy is to pause a video (or demonstration) in the middle and ask students to justify predictions about what they think might be going to see next.  It really does work!

If you are committed to having students watch a really great, but hour long video presentation—like COSMOS—then the cardinal rule is that instructors need a scheme to help students intellectually participate in and interact with the ideas in the video.  Motivated because we are trying to improve the different Internet-based, asynchronous distance learning astronomy courses we teach, we have been experimenting with STUDENT VIDEO DISCUSSION GUIDE worksheets.

Student Video Discussion Guide

Student Video Discussion Guide

The general idea underlying the STUDENT VIDEO DISCUSSION GUIDE is to keep the student intellectually engaged with the video while it is playing.  Leveraging Bloom’s Taxonomy, we present the students with three distinct levels of questions.  For an hour-long video, we first ask four to eight factual, knowledge-level questions from the video.  An example is, How far above Earth’s surface is the Hubble Space Telescope?  The point of these first-tier questions are to help students focus on the more relevant facts shared in the video.  The second thing we pose to students are two to four deeper level, synthesis and evaluation questions from the video.   An example is, “Were the Hubble’s observations of Mars or Saturn the most scientifically valuable?”  Finally, we post one or two self-reflection questions.  The point of these questions is to attempt to make the information in the video more emotionally relevant to students so that they have a better chance of internalizing the ideas.  An example of one of these self-reflection questions is, “Of the many Hubble images shown, which 12 HST images would you pick to use in a calendar and why?” To be clear, we give the students the questions on the STUDENT VIDEO DISCUSSION GUIDE before the video starts and encourage them to look over the questions before the video starts so that they know precisely what that are looking for while watching the video. You can find many examples of these STUDENT VIDEO DISCUSSION GUIDES in the Astronomy Faculty Lounge at by searching the resources under VIDEOS.

We began this discussion by saying, NO, you really shouldn’t use videos in your classroom. In the end, I don’t really believe that—I was trying to catch your attention by being a bit contrarian.  The truth is that there are amazing video resources available for teaching astronomy.  However, astronomy education research clearly shows that it is irresponsible just to turn on the video as a classroom babysitter and hope that students will benefit.  Like using textbook reading assignments, LECTURE TUTORIALS FOR INTRODUCTORY ASTRONOMY, or online homework systems, videos too need to have a specific educational purpose for their inclusion and their rationale explained to students to generate their buy in.  In other words, for videos to be effective, you need to successfully convince students that the videos used will specifically help them get a better grade in your course and, most importantly, will help students learn more astronomy.

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To Textbook or Not To Textbook? That is the question.

Tim Slater, CAPER Center for Astronomy & Physics Education Research,

Even before I became a textbook author, I was party to more than one water cooler conversation about whether or not faculty should require students to purchase textbooks [viz.,].  Now, that I am an introductory astronomy textbook author, I still feel the same way—there are some benefits to assigning a textbook to students and, more importantly, tremendous risks in not doing so.

Most folks who have moved away from textbooks entirely face a pretty serious problem in that the professor, and the professor’s notes, all too often can become the sole source of knowledge and expertise in the class.  Sure students CAN go look up stuff and get another perspective, but my sense is that they don’t, and perhaps don’t even know how to do so effectively given the variety of presentations professors give.  In the case where there is no clear supporting textbook readings assigned to students, the end result is an implicit and sizeable pressure on students—probably completely unintended by the professor— to memorize nearly everything that their professors say (or type onto a PowerPoint slide).  It is these “memorized transcripts” that end up being what students are able to answer on exams. At the same time, a hidden social contract in the introductory astronomy class causes professors themselves to feel a sizeable pressure to only ask questions about what they specifically talk about in class.  For my money, this is a LOSE-LOSE bet.  When I consider all of this, it seems to me that the astronomy professor’s job should be about linking students’ thinking to the ideas of astronomy and giving students feedback about how well they are learning the concepts, not about being responsible for delivering astronomy ideas in their entirety.

Coming of Age in the Milky Way by Timothy Ferris
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-free writing of coffee table books.  

There is a dark side here, in that some students are preferentially disadvantaged more than other students when astronomy faculty purposefully choose not to assign readings connected to their teaching from a textbook—those are the students who already struggle with learning from your lecture.  CAPER’s Stephanie J. Slater argues in Astrolrner Post #5014:

Stephanie J. Slater, Ph.D. CAPER Center for Astronomy & Physics Education Research

Stephanie Slater

Teaching using a textbook as a tool is pedagogical skill well worth learning.  There is ample research out there that suggests that texts are important resources for many students, including those students who are most in need of extra help.  Many students cannot take notes and listen to lecture at the same time.  Students with specific learning disabilities, reduced working memories, who are second language learners, or who have poor spatial reasoning skills, struggle to glean concepts and facts from lecture.  Non-text readings that are not structured with the coherence usually found in a textbook, or with the learning cues found in many texts, make life harder for our students who have ADD, reduced working memory, who are visually impaired, have visual-neurological dysfunction, or who have  reduced access to technology.

So, for my money, I think using an astronomy textbook is an important part of the introductory science survey course.  Yes, they can be expensive, but in the grand scheme of things that go into a college education, textbooks really aren’t.  My most convincing evidence is that the $45 that students pay for the LECTURE TUTORIALS FOR INTRODUCTORY ASTRONOMY initially seems outrageous for a “work book” BUT, students rarely complain because they really, really use the book as part of their learning and they find it valuable.  If students felt that the astronomy textbook helped them learn the material and they found it valuable, they wouldn’t care if it cost $235 (of course, if you haven’t looked at the half priced e-books or loose-leaf for students as an significantly lower cost option, you should talk to the next textbook sales representative that comes through the door – these lower-price alternatives are getting really attractive!).

I think the consistent problem that most astronomy faculty face related to textbooks is nothing short of simply OPERATOR ERROR.  If professors never ask students to be responsible for learning from the textbook without the instructor repeating or, even worse, and I’ve seen it, reading from the textbook during lecture, then why would students ever think a textbook is valuable.  This problem is much better documented in physics than astronomy, where too many physics professors don’t’ use the textbook for anything other than problems at the end of the chapter.  Eric Mazur says that, even at Harvard, students won’t read unless you require it of them.  My experience is that this applies no matter what your student demographic is. (I add this additional provocation for those who are about to say, “but my community college students couldn’t possibly read the book.” I don’t see any truly convincing evidence of this–readability on astronomy books show that many are purposefully done at pre-high school reading-level anyway.)

Investigating Astronomy Textbook by Tim Slater and Roger Freedman

Speaking for a moment as a textbook author, one thing that I have definitely learned is that no textbooks end up being perfectly accurate – even after tens of people read and comment and carefully check the drafts.  Errors do somehow frustratingly slip through the textbook creation process—and some faculty out there love to find and point out those errors!  However, I’m absolutely sure that if 25 experts were to look at your PowerPoint slides and listen to your lectures, very few of any of us are error free in our presentations.  Unless you’ve had 25 experts review your lectures, you’re probably guilty of giving out some misinformation.  Textbooks at least have had some (gulp, a lot, usually) expert review.  The other thing I’ve learned that I didn’t fully understand before is that modern textbooks have pedagogical tools, as mentioned above, that really do matter to novice readers.  Websites, nor trade books, often have these things that really do help students learn the material more efficiently, particularly struggling ones.

My thinking is that students should be required to learn from the textbook and that portions of exams should be allocated to material from the textbook that is NOT specifically covered in lecture, but students are specifically made aware of what they are to learn.  I don’t want to spend my valuable class time telling them facts they can read in a much more precise and attractive language than I can “say” during class time.  This doesn’t mean that you should abdicate your responsibility to helping students learn—however, if you are only asking your students to memorize what you say in class, you are missing a grand opportunity to teach students how to find, understand, and internalize material on their own.  And, for many of us, we hope that we are helping our students, at least a little bit, become more talented life-long learners.


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Educational Underpinnings of Backwards Faded Scaffolding and Engaging in Astronomical Inquiry

Tim Slater, CAPER Center for Astronomy & Physics Education Research,

Students’ Personal Theories of Learning

It’s all too easy to forget that what students hold as their personal definition of learning. In other words, theories of learning teachers hold isn’t the only thing that matters; what also matters are the theories of learning astronomy students hold themselves. Perhaps surprisingly, theories of learning students hold can be an influential consideration on the part of teachers when making instructional decisions.  If students and teachers have very different views on what it means to learn astronomy, then conflict is certain to exist. If this theoretical conflict isn’t resolved, then the practice of teaching and learning astronomy is likely to fail.  Moreover, because students’ theories of learning are often hard earned through years of taking and being graded on tests, they are likely to be deeply entrenched.  In addition, students’ theories of learning are often culturally-based, and sometimes even gender-based, giving considerable inertia to their definitions of what it means to learn resulting in something arduously difficult, if not impossible, to move.

On one hand, students may have come to believe that learning is synonymous with memorization.  In other words, if students can repeat word-for-word the definitions given to them by their astronomy teacher, then they have learned astronomy.  Award winning secondary level astronomy teacher Keith Goering from the Midwestern US, is famously known for joking, “if you can says it, then you must knows it.”  Students who have adopted this definition of learning are characterized by making flash-cards on small pieces of two-sided paper with bold-faced vocabulary words on one side and text-book definitions on the other side.  If they were to fail a test, the only reasons could be that the instructor asked purposefully tricky or deceptive questions or that the students themselves simply didn’t work hard enough to memorize a sufficient number of details.  Many students have become convinced that memorization is equivalent to learning because such a factual perspective has been represented to them on test after test after test over their broad school experience.

On the other hand, students may believe that learning requires much more than memorization, but requires deep understanding.  For most students, the notion of understanding is probably somewhat ill-defined. For scholars, there are a variety of ways to characterize understanding.  The most common description of understanding used in the US is that of thinking about understanding ranging from having a shallow and superficial knowledge of an idea to that of holding deep understanding.  Widely attributed to University of Chicago Professor Benjamin Bloom and known as Bloom’s Taxonomy, this decades-old hierarchical description of understanding is a six-level description ranging from shallow learning (i) knowledge and (ii) comprehension to a more moderate understanding of (iii) application and (iv) analysis to the deepest levels of understanding  of (v) synthesis and (iv) evaluation.    In contrast, more recently scholars have been describing understanding as being flexible and multi-faceted—a horizontal view rather than a vertical view if you will. Widely popularized in the US by Grant Wiggins and Jay McTighe (2005) in their Understanding by Design work, a complete understanding of an idea can be also described as having six different facets: Explanation, Interpretation, Application, Perspective, Empathy, and Self-Knowledge.  In the end, whichever scholarly description of understanding students adopt implicitly or explicitly, the stark distinction between understanding and memorization is pronounced and strongly poised to influence how students approach the learning of astronomy.  Most importantly, students’ views and their teachers’ theories of what it means to learn astronomy—and what their grades mean—benefit greatly from being aligned.

Astronomy by Inquiry: A Highly Student-Centered Instructional Strategy.  For many years, it has been common practice to ask students to complete astronomy assignments and astronomy laboratory exercises in the process of learning astronomy that look absolutely nothing like what astronomers actually do.  For example, countless astronomy students have used pencils to trace out ellipses with loose string on small square-box graph paper and count tiny squares to “prove” Kepler’s Laws of Planetary Motion.  Perhaps even more students have carefully plotted the precise right ascension and declination positions of hundreds of stars to re-create the constellations and asterism of the night sky on small square-box graph paper to make their own star maps—star maps that are rarely ever used. If a teacher believes, instead, that students learning astronomy should actually be doing astronomy, then the traditional activities need to be discarded.  Undoubtedly, this is not the creative and imaginative work that characterizes astronomy.

moving-from-teacher-centered-to-learner-centered-versionARecently, work by Stephanie Slater and colleagues (2010, 2013) at the CAPER Center for Astronomy & Physics Education Research in the USA has focused on developing learning experiences purposefully designed to mimic that daily work of a research astronomer. Known awkwardly as BACKWARDS FADED SCAFFOLDING LABS for historical reasons, this approach uses an underlying learning theory that states that novice students need extended and repeated engagements with scientific investigations in order to develop skills at participating in scientific inquiry (These are published by Stephanie Slater and colleagues under the name ENGAGING IN ASTRONOMICAL INQUIRY).  To leverage this idea of the importance of repeated intellectual engagements, the backwards faded scaffolding labs ask students to complete five shorter scientific investigations on a topic, as opposed to the conventional approach pursuing a single, longer scientific investigation.

The reason that these BFS labs are referred to as scaffolded, is that students are led through a specific instructional sequence where students are initially provided substantial amounts of support.  The instructor-supplied student support is slowly removed over the course of the laboratory learning experience—such that the lessons scaffolds are faded.  By the end of each lesson, students are able to devise and complete a scientific investigation in astronomy all on their own.  In this way, students gain confidence in their ability to conduct scientific inquiry in astronomy by gaining more responsibility for the learning from the beginning to the end of instruction.

The BFS labs are also known for being backwards because of how the scaffolds are carefully faded.  In the most common instructional approaches where students are taught how to conduct scientific inquiry, teachers teach scientific inquiry in three phases.  The first phase is to teach students how to ask scientifically fruitful questions. Second, students are taught to design experiments and observations to pursue evidence.  Finally, students are typically taught how to extract evidence from data and create an evidence-based astronomy conclusion.

What is particularly unique about these learning astronomy BFS laboratory learning experiences is the recognition that teaching students to ask scientifically fruitful questions is by far the most difficult aspect.  In response, the BFS astronomy lessons teach students to create and defend evidence-based conclusions first from a given research question and given data.  Then, students are taught to devise strategies to pursue data that can be used in an evidenced-based conclusion for a new research question, which is also provided for them.  Only when students have had considerable experience designing observations and defending conclusions from a number of research questions, are students then taught to create fruitful research questions—now that they have considerable experience doing the processes of scientific inquiry in astronomy.

An instructional sequence in scientific inquiry might be to ask students to use an online database of solar system planets showing the planet and moon positions and motions to pursue a series of investigations.  An example series of investigations might be to (i) determine the length of time our Sun spins by monitoring sunspots moving across the surface, (ii) determine how long it takes Jupiter to spin by monitoring the reappearance of Jupiter’s Great Red Spot, (iii) determine how long it take Io to spin, (iv) determine how long it takes Io to orbit Jupiter, and (v) create your own research project on motions of the solar system. Two consistently great resources for this can be found by searching the Internet for NASA EYES ON THE SKY and JPL SOLAR SYSTEM SIMULATOR. But what is vitally important here is that in each case, students are deeply engaged in a progressive series of questions, where the teacher gives substantively less support with each following investigation.

Several thousand astronomy students have used these Backwards Faded Scaffolding inquiry materials with varying degrees of success.  By and large, our experience is that most people who have used them, continue to use them course after course.  At the same time, talented teachers are creating their own BFS labs to cover concepts across the domain of astronomy, and even moving into other disciplines.  For one, there is an online discussion group e-community for BFS-Labs that you can join by heading over to  There is even a YouTube video on backwards faded scaffolding Many of these new and community created BFS-Labs are archived and freely available at the Astronomy Faculty Lounge which can be accessed through a portal at the CAPER Center for Astronomy & Physics Education Research website at (Slater & Slater, 2013).

Concluding Thoughts about Influences of Theory and Practice in Teaching Astronomy

In moving from a teacher-centered classroom to a learner-centered classroom, teachers need to sometimes make dramatic changes in their adopted underlying philosophies of teaching astronomy and guiding theories of learning.  In particular, classrooms that greatly value respect students thinking, start where the students are cognitively, and move all students as individuals are learner-centered.  In contrast, in a teacher-centered classroom, all students learn the same facts and the goal is to get them all to the same ending place.  How one decides to teach relies heavily on what the end goal is.  Teachers have different end goals, and as a result, should have different teaching approaches (see Slater & Zeilik, (2003) for numerous examples of various astronomy teaching approaches).

There are undoubtedly some teachers who loudly state they hold a particular teaching philosophy and use specific theories of learning that are actually in direct conflict with what is observed in their classroom.  In other words, there can be large differences between stated theory and actual classroom teaching practice.  Sometimes this is completely unintentional in that a single teacher cannot themselves know all of the possible teaching strategies and it does happen that a teacher doesn’t know how to teach in a way that is consistent with their stated theory.  More often, though, teachers know what the culturally accepted theory of teaching is, and purposefully use something different in the practice of teaching.  This conflict can lead to tremendous challenges between different teachers of similar topics.

As we look toward the evolving future, it is perhaps the concept of “The Flipped Classroom” that has the greatest potential for making classroom’s more learner-centered.  A far too brief description of flipping the astronomy classroom is a classroom in which the students do homework assignments and activities in the classroom in front of the teacher and students hear lectures and receive new astronomy information outside of class, usually being given information through Internet videos (Slater, 2013).  In other words, the process is flipped about where students do homework and where students listen to lectures.  This approach hold the best promise so far for helping teachers become learning coaches rather than information dispensers and moving toward being more learner-centered.

Mike Bennett, Previous Director of Astronomical Society of the Pacific

A recent beloved Executive Director of the Astronomical Society of the Pacific, Mike Bennett, the well-respected astronomy and planetarium educator was well known for the quip, “You know what the difference between theory and practice is?  In theory, there is no difference between theory and practice.  However, in practice, there is!”  If you understand why you make the teaching decisions you make, then you are much better positioned to make consistent decisions about which of the many teaching innovations available will best fit into your continuous effort at improving your teaching and your students learning in astronomy.


Slater, S.J., Slater, T.F. & Bailey, J.M. (2011). Discipline-Based Science Education Research: A Scientists’ Guide, 2011. W.H. Freeman Publishing and Company, New York. ISBN 1429265868.

Slater, S.J., Slater, T.F. & Lyons, D.J. (2010). Engaging in Astronomical Inquiry. W.H. Freeman Publishing and Company, New York. ISBN 1429258608.

Slater, S.J., Slater, T.F. & Lyons, D.J. (2011) Teaching Scientific Inquiry with GalaxyZoo. The Physics Teacher, 49(2), 94-96.

Slater, S.J., Slater, T.F., and Shaner, A. (2008).  Impact of Backwards Faded Scaffolding in an Astronomy Course for Pre-service Elementary Teachers based on Inquiry.  Journal of Geoscience Education, 56(5), 408-416.

Slater, T.F. (2013). Would a Cognitive Scientist Recommend a Flipped Classroom? – Ramblings about Flipping the Astronomy Classroom, Over Easy.  An online blogged essay at the Astronomy Faculty Lounge Blog at URL:

Slater, T.F. & Slater, S.J. (2013).  Next Generation Astronomy Faculty Lounge.  Online teaching resource library and community forum hosted by CAPER Center for Astronomy & Physics Education Research, URL:

Slater, T.F. & Zeilik, M. (2003). Insights Into the Universe:  Effective Ways to Teach Astronomy, American Association of Physics Teachers Press: College Park, MD (160 pages).  ISBN:  1-931024-04-9

Wiggins, G. P., & McTighe, J. (2005). Understanding by design. Association for Supervision & Curriculum Development, Publishers.

Waller, W.H. & Slater, T.F. (2011) Improving Introductory Astronomy Education in American Colleges and Universities: A Review of Recent Progress. Journal of Geoscience Education, 59, 176-183.

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Educational Underpinnings of Lecture-Tutorials for Introductory Astronomy

Tim Slater, CAPER Center for Astronomy & Physics Education Research,  

Theories of Learning focused on the Student

It is all too often easy to forget that learning theories obviously or quietly influence what classroom environments look like. On one hand, theories of learning used in classrooms where the teacher is the expert source of all knowledge are known as TEACHER-CENTERED classrooms.  This is where the learning theory guiding the classroom put the teacher in the role to perform and present—perhaps download—information and ideas to the class.  Teacher-centered classrooms are focused on the performance and presentation of the teacher, and improving these classrooms focus on the teacher being the one to be making better presentations and better lectures with better illustrations, examples, and analogies.  On the other hand, classrooms could be focused on what students are doing every day instead of what teachers are doing. This perspective is in stark contrast to that of student-centered classrooms, or LEARNER-CENTERED teaching. Improvements in learner-centered classrooms instead focus on changing the student experience by having students talk about and sort out concepts, rather than being told what they should think and believe about scientific ideas.  Although it isn’t clear than one is always better than the other, what is certain is that learning theories driving the design and operation of learner-centered classrooms look very different.

A contrasting theory of learning that is more learner-centered is that of CONCEPTUAL CHANGE.  Widely advocated by US-based Peter Hewsen and his talented colleagues like Strike and Posner (1982, 1992) in the later Twentieth Century, conceptual change is based on the notion of teaching students who enter learning already holding ideas they have developed with considerable mental effort.  In response, it is the job of the teacher to build an environment that exposes students’ initial ideas, challenges the students’ thinking, and replaces the pre-existing astronomy ideas with new and better ideas.  Long-time physics education researcher Lillian Chris McDermott and her colleagues (2001) at the University of Washington (USA) describe teaching aligned with this theory of learning as elicit, confront and resolve. Clearly, classical conceptual change in astronomy teaching has an underlying commitment to the teaching philosophy of constructivism, as briefly described above.

For a teacher who subscribes to conceptual change as a theory of learning, a teacher’s job is to find and help students replace their astronomy misconceptions with scientifically accurate ideas.  Whereas a positivist instructor would hold the position that simply telling students that they have a misconception and that the correct ideas should over-write the incorrect ideas, a teacher subscribing to conceptual change believes that new ideas will only be considered if there is dissatisfaction with old ideas. Moreover the newly proposed ideas have to be completely understandable and be able to better explain a wider range of ideas than the old ideas for conceptual change to successfully apply.

moving-from-teacher-centered-to-learner-centered-versionAEarly classroom applications of conceptual change were focused on using a three-phase learning cycle, advocated widely by Karplus and Butts (1977).  The first phase of such a learning cycle is exploration were students wrestled with a phenomena or observation that was unexpected, known in education circles as a decrepit event, and presented to astronomy students without an explicit agenda revealed by the teacher.  Some example decrepit events in astronomy teaching might be: (a) if it is hotter in the summertime because we are close to the Sun, why might the northern and southern hemisphere seasons be reversed?; (b) if our Moon has no gravity, how did astronauts successfully walk on our Moon?; (c) if planets spin more slowly the farther they are from the Sun, why might Jupiter spin faster than Saturn?; (d) if main sequence stars move on the HR diagram toward the right when they run out of useable fuel in their core, just where might they move to in outer space?; and (e) if we can determine which direction our galaxy is moving in an evolving Universe by looking for redshifts in one direction and blue shifts in the opposite direction, what might it mean if we observe red shifts in all directions?.

The second of the three phases in the classical learning cycle is that of concept introduction.  In this phase, astronomy teachers are to tie the descript event to the scientifically accurate idea, usually through a didactic, lecture-based strategy.  It is in this phase where students are introduced to the accurate scientific vocabulary that better describes the ideas they wrestled with in initial the exploration phase. This cycle is then closed by a third phase known as concept application, where students are to practice applying their new thinking in novel applications. Taken together, a teaching practice aligned with this theory is to repeatedly have students engage with phenomena and come to a more meaningful understanding.

In the decades following Karplus, this three-phase approach has been expanded to a five-phase approach.  Advocated by US science educator Roger Bybee (2002), who was then working in the domain of Biology Education, the 5E approach has gained favor among teachers and curriculum developers.  The 5E approach phases are Explore, Engage, Explain, Extend, and Evaluate.  Whether a teacher thinks the better teaching practice here is to use a 3-phase or a 5-phase, or even a 10-phase learning cycle, the underlying theory here is that students will better learn an astronomical concept if they have targeted and repeated engagements with the idea, rather than a single, isolated experience.  Where these student-centered learning phases starkly contrast from the teacher-centered information download practice of teaching is that students’ initial ideas are taken to be serious and influential parts of the learning process and purposeful mechanisms exist to include, alter, and extend students’ thinking.

In recent years, conceptual change theory has been more serious modified to include students’ attitudes and motivation for learning.  The changes in conceptual change theory are due in large part, to a broad failure for conceptual change learning cycles to work with emotionally-laden topics.  Astronomy teachers using conceptual change have often noticed that providing students with discrepant events and data intended to cause internal cognitive conflict driving conceptual change in particular domains had little to no impact.  Most notably, the astronomy topics seemingly largely immune to conceptual change were: astrology as influencing human events, Big Bang Theory of the creation of universe (Prather, Slater, Offerdahl, 2002), the Expanding Universe, evolution of planetary atmospheres as a result of biological evolution, and anthropogenic (human-caused) planetary climate change, among others.  In other words, in the practice of teaching through conceptual change, no amount of data or logical argumentation seemed to alter some students thinking about such issues.  In response, parts of conceptual change theory have been altered to account for emotionally-laden issues where students’ self-identity is threatened by a particular scientific idea.  Known widely as “hot” conceptual change theory, the teaching practice that shows some promise for enhancing student’s thinking in these domains is one of having students evaluate the thinking of other people from afar, perhaps as case studies or consideration of mini-debates among other people, rather than engaging the students’ own thinking.  The underlying idea is that students will more readily evaluate the thinking of others than themselves.  Such practices are seen as less risky to students’ self-identity and allow for a considerate teacher to more respectfully present and challenge opposing points of view.  (For more on this hot conceptual change, see work by US science educator Doug Lombardi and his colleagues (2010) in this domain.)

Lecture-Tutorials for Introductory Astronomy: An Instructional Strategy In-between a Teacher-Centered and a Student-Centered Approach.  To take advantage of students’ needs to have guided and extended experiences in understanding a new idea, Jeff Adams and Tim Slater, then at Montana State University in the US, led a team developing a series of instructional materials called LECTURE TUTORIALS FOR INTRODUCTORY ASTRONOMY (Prather, Slater, Adams & Brissenden, 2004 & 2012).  Lecture Tutorials were designed to combine the advantages of SOCRATIC DIALOGUE teaching approaches with the collaborative activity benefits from THINK-PAIR-SHARE.

Lecture-Tutorials are carefully designed worksheets that students collaboratively complete in pairs.  Each worksheet takes 10-15 minutes to complete and is used during class time after a short lecture to help students extend their understanding and demonstrate the power of astronomy models.  Upon inspection, the questions posed on the worksheets are similar to the series of questions a considerate teacher might ask a struggling student if they were tutoring the student in a one-on-one face-to-face setting after class.  In this way, Lecture-Tutorials are designed to move students from a novice understanding of an idea to a more comprehensive understanding (Brogt, 2007).

A strategy highly characteristic of these worksheets is to ask students to evaluate a conversation between two students.  Often described as a MINI-DEBATE (see Slater, 2010), the worksheets provide a short quoted dialogue between two students.  For example, one student might be portrayed as saying to another student, “the Moon has not water because it has no gravity” who then responds by saying, “The Moon does have gravity, like any other planet, and the Moon’s water is frozen as un-melted ice in deep craters that never are exposed to sunlight.”   The learners using the Lecture-Tutorials for Introductory Astronomy are then asked to craft a response to the question of which student, if either, do you agree with.  In this way, students are given the opportunity to safely judge the accuracy of distant hypothetical students’ thinking rather than directly confront their own personal thinking.  In this sense, the task is less risky than revealing their own personal views and are apt to take more risks at exposing their own potentially incorrect thinking, thus positioning themselves to learn complex astronomy ideas themselves.

More than 100,000 astronomy students have used Lecture-Tutorials with varying degrees of success.  By and large, our experience is that most people who have used them, continue to use them course after course.  At the same time, talented teachers are creating Lecture-Tutorials to cover concepts across the domain of astronomy, and even moving into other disciplines.  There is even a 15-min. YouTube video on how to make your own available at

Many of these new and community created Lecture-Tutorials are archived and freely available at the Astronomy Faculty Lounge which can be accessed through the FACULTY LOUNGE portal at the CAPER Center for Astronomy & Physics Education Research website at (Slater & Slater, 2013).


Brogt, E. (2007). A theoretical background on a successful implementation of lecture-tutorials. Astronomy Education Review, 6, 50.

Bybee, R. W. (Ed.). (2002). Learning science and the science of learning: Science educators’ essay collection. National Science Teachers Association, Publisher.

Karplus, R., & Butts, D. P. (1977). Science teaching and the development of reasoning. Journal of Research in Science Teaching, 14(2), 169-175.

Lombardi, D., & Sinatra, G. M. (2010). College students’ perceptions about the plausibility of human-induced climate change. Research in Science Education, 1-17.

McDermott, L. C. (2001). Oersted Medal Lecture 2001:“Physics education research—the key to student learning”. American Journal of Physics, 69, 1127.

Prather, E.E., Slater, T.F., Adams, J.P. Bailey, J.M., Jones, L.V., & Dostal, J.A. (2004). Research on a Lecture-Tutorial Approach to Teaching Introductory Astronomy for Nonscience Majors.  Astronomy Education Review, 3(2), 122-136.

Prather, E.E., Slater, T.F., Adams, J.P. & Brissenden, G. (2012). Lecture-Tutorials for Introductory Astronomy – 3rd Edition , Addison Wesley, ISBN:  0132392267

Prather, E. E., Slater, T. F., & Offerdahl, E. G. (2002). Hints of a fundamental misconception in cosmology. Astronomy Education Review, 1, 28.

Posner, G. J., Strike, K. A., Hewson, P. W., & Gertzog, W. A. (1982). Accommodation of a scientific conception: Toward a theory of conceptual change. Science education, 66(2), 211-227.

Slater, T.F. (2010). Enhancing Learning Through Scientific Mini-Debates. The Physics Teacher, 48(6), 425-426.

Slater, T.F. & Slater, S.J. (2013).  Next Generation Astronomy Faculty Lounge.  Online teaching resource library and community forum hosted by CAPER Center for Astronomy & Physics Education Research, URL:

Slater, T.F. & Zeilik, M. (2003). Insights Into the Universe:  Effective Ways to Teach Astronomy, American Association of Physics Teachers Press: College Park, MD (160 pages).  ISBN:  1-931024-04-9

Strike, K. A., & Posner, G. J. (1992). A revisionist theory of conceptual change. Philosophy of science, cognitive psychology, and educational theory and practice, 147-176.



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Educational Theory Underlying Astronomy Clicker Questions & Peer Instruction

Tim Slater, CAPER Center for Astronomy & Physics Education Research,

As teachers, we make countless decisions about our classrooms every day. Some of them are obvious: “Am I going to talk about planets before stars today, or the other way around?” Others decisions are so subtle, they might go unnoticed: “Am I going to carefully grade every aspect of this assignment, like spelling and grammar, or am I just going to skim to see if this student has acquired the general idea?” With so many decisions to be made every day, you might think we’d be exhausted before we ever talked to a single student. And, we would, if it were not for the underlying philosophies about teaching and theories about learning that we carry with us to help us make these decisions. All too often, these philosophies and theories are completely unexamined, tacit if you will. Most importantly, if you want to improve your teaching effectiveness, understanding which philosophies and theories of learning you have adopted will allow you to make improvements in your students’ learning. Let’s consider some of the more prevalent theories and practices in teaching astronomy and see if you can gain some insight into how you are making decisions about your classroom.

Two Contrasting Philosophies about Teaching Astronomy

POSITIVISM. Undoubtedly, the dominant philosophy driving most of teaching is one based in positivism. In brief, and with sincere apologies to philosophers who have spent lifetimes eloquently describing the aspects of this philosophical position, positivism is based on a notion that we only learn what we have been told or directly experienced. An astronomy teacher who devises instruction based on a positivist philosophy of teaching expends considerable effort on delivering precisely articulated lectures with cleverly illustrated graphics and illustrations. They believe that students do not know anything about the Universe before entering their classroom and it is their task to clearly describe the nature and mechanics of the world to self-motivated students who should be intrinsically eager to experience their lecture. They disappointingly view disinterested students as unfortunately individuals who are choosing to miss a rare opportunity to learn. Most importantly, most positivist teachers believe that a lecturers’ enthusiasm is probably the most important aspect to gaining and keeping student attention so they can learn. Among college and university professors, this is clearly the most widely adopted philosophy of teaching. At secondary levels, this is somewhat less prevalent, but still dominant. In this instance, the theoretical position, which is really a philosophical one, is that students learn astronomy by attentively listening to precisely delivered astronomy lectures and the practice consistent with this view is to provide accurate, professor-centered instruction where the teacher, or by proxy the teacher’s assigned readings, is the sole source of information and learning in the course. Students’ are assigned homework or in class activities designed to practice reciting or applying the teacher-delivered procedures—tests are more of the same.

CONSTRUCTIVISM. Perhaps the most influential teaching philosophy driving innovation and reformation in astronomy teaching is that of constructivism. Constructivism is grounded in the notion that students enter your classroom already holding pre-existing ideas about the way the world works. In this context, students enter your classroom already knowing why it is hotter in the summer than in the winter, why the leaves change color in autumn, and why rain falls from clouds. Many of the ideas and explanations students hold were constructed with considerable mental effort and students deeply own and are committed to holding on to their ideas. The problem for the astronomy teacher is that some of the student-created explanations about how the Universe works are scientifically accurate, whereas many others are completely wrong.

In the late 1960’s, noted educator David Ausubel (1968) was well known for saying that “the task of the teacher is to determine what the student already knows and teach them accordingly.” In response, much of the astronomy education research since that time has focused on devising strategies to measure the range and domain of students’ misconceptions in astronomy. The number of tests for measuring the knowledge and conceptual knowledge in astronomy is a lot and these surveys and tests have evolved considerably over the years. Currently, the best landscape survey we know of is probably the TOAST Test Of Astronomy STandards (see Slater, Slater & Bailey, 2011). The driving force behind the effortful construction of such surveys is to carefully determine what students initially think they know about astronomy as they come into the classroom so that the constructivist teacher can teach the students accordingly. Constructivist astronomy teachers pay careful attention to the results of these surveys and tests.

A constructivist teacher recognizes that their students already hold ideas about astronomy, some correct, some incorrect, and many partially correct. As a result they spend considerable energy questioning students to find out what they think. In real-time response to their questions, constructivist teachers continuously query their students about examples and counter examples and provide students with metacognitive feedback about their own evolving ideas. Most constructivist teachers realize that students don’t simply move from the wrong idea to the correct idea, but that there is long, convoluted journey with multiple pathways in leading students to more complete and scientifically accurate ideas. Teachers who hold a constructivist teaching philosophy tend to be more open to trying different teaching innovations as compared to their positivist philosophy holding colleagues. In this context, the theory is that the teacher’s job is to move students from naïve understanding and misconceptions to scientifically accurate understanding of astronomy. The practice aligned with this philosophical position is that teachers are not only dispensers of knowledge, but rather serve as coaches and guides for students who are responsible for the learning. Homework or in-class activities then take the form of aligning student thinking with scientific thinking, often making use of collaborative groups (Adams & Slater, 2002).

moving-from-teacher-centered-to-learner-centered-versionAThese are not the only two teaching philosophies, but rather represent two opposite ends of a philosophical continuum. Perhaps, when thinking about how these perspectives are manifested in the classroom, this continuum is better described as a teacher-centered to learner-centered classroom continuum. In the teacher-centered classroom, the teacher is the primary source of information and ideas, and is characterized by the teacher doing most of the talking. In contrast, in the learner-centered classroom, the students are doing most of the talking, debating, and articulating of ideas—often talking to each other rather than to the teacher.

Theories of Learning Focusing on the Teacher

If you understand that there is a continuum of different teaching philosophies, you probably wouldn’t be surprised that there are a number of theories of learning as well. There are far too many theories of learning to describe in this short space, but a few are worth describing because an awareness of learning theories help us to better describe why we do what we do in our astronomy teaching.

For teachers who are inclined toward a positivist philosophy of teaching, briefly described above, their most likely corresponding theory of learning is that of TABULA RASA. As eloquently described by Vosniadou (1998), Tabula Rasa can be literally translated as “blank slate.” Teachers who subscribe to a Tabula Rasa theory of learning view their students as essentially having a blank slate in their heads about astronomy. They view their job as an astronomy teacher is to write precise information in students’ empty minds. In general, they do not believe that students hold a pre-existing understanding about the size and shape of the Universe, the physical processes that cause stars to shine, or about how planetary surfaces change. More important to our discussion, when these instructors do agree that their students have misconceptions about astronomy, they strongly believe that students need to be told more clearly, if not more loudly, the correct ideas and that these correct ideas will simply erase and over-write any old or incorrect ideas. This is highly characteristic of a teacher-centered approach to teaching, particularly those who teachers who spend most of their time at the front of the room lecturing to students who are taking notes to memorize later.

At the same time, teachers who hold a Tabula Rasa theory of learning implicitly believe that students will most value and record the information told to them by the instructor with the highest credentials. When students fail to learn from an instructor who holds a Tabula Rasa view of learning, either it is the students fault for not fully being attentive during class. If the teacher receives blame for insufficient learning, the most common intervention is to ensure that the failing teacher fully understands the science underlying what they are trying to teach, often by requiring them to sit in on some graduate-level astronomy course to refresh and improve their understanding of astronomy at the most complex levels.

Astronomy Clicker Questions: Teacher-Centered Instructional Strategy. Learning theories adopted driving teacher-centered classrooms do not always look like a lecture-based classroom. A classroom setting that looks very different, but still driven by a theory of learning focused on the teacher being the expert who moves information from themselves to the student, is a classroom based on notions of SOCRATIC DIALOGUE. Socratic dialogue is a learning theory based on the idea that if students are simply asked the correct questions in the correct sequence that the student themselves will come to know an idea. Although lecture is a teaching strategy on could adopt and use no others, a more common strategy for intellectually engaging students with questions to think about and debate is Think-Pair-Share, also known as Clicker Questions and described in detail elsewhere (see, for example, Slater, 2008).

THINK-PAIR-SHARE is an approach where the teacher presents an idea in a traditional lecture format and then asks students to stop taking notes and answer a question about the ideas they were just presented. Questions posed by the teacher to the students can either be simple recall (e.g., which planet has the highest surface temperature?) or can be questions of application (e.g., at which phase of the moon will a solar eclipse occur?). Less often, but still quite effective at improving students’ achievement, teachers can pose questions encouraging students to encounter a widely known misconception (e.g., how often does the Moon’s appearance change?).

What makes this approach different than simply interjecting questions to the entire group of students in a lecture is that the teacher directs this process in three distinct steps: (i) As an opening step, the teacher poses the question to students who must personally and privately commit to an answer without speaking to anyone. Traditionally, this is done after some lecturing has occurred. (ii) Next, the teacher asks students to vote on the question’s answer. There are two important reasons for this second step. The first reason is that students need to be held accountable for devising an answer to the question; if the students do not give a meaningful attempt to answer the question to the teacher, then the students haven’t actually engaged intellectually with the idea being taught. The second reason is that the teacher too needs to understand the extent to which students understand the topic so that they can decide if more lecture needs to occur. If most of the students have the correct answer, then the teacher can move on with the lecture. On the other hand, if most of the students have an incorrect answer, then the teacher needs to re-teach the idea, perhaps in a different way with different illustrations, examples or analogies.

As a brief aside, this think-pair-share approach of asking students to answer and then provide their answer to the teacher requires the teacher to have an infrastructure or system by which to get students’ answers. Experienced teachers know that if they ask students to share their answers in front of the rest of the class, rarely will more than one or two students volunteer an answer freely. It is possible to randomly call out student names and ask them to provide an answer—one such strategy is to write student names on pieces of paper or popsicle craft sticks and then randomly draw a students’ name—but this astronomy teaching practice can be risky because some students are simply unable to speak confidently in front of the rest of their classmates. Instead, a common practice is to give students a sheet of paper or a small chalk or re-useable white board on which they can write their answers in big letters and then simultaneously all hold up their answers for the teacher to see and evaluate. This approach to having students hold up their solutions on a piece of paper or erasable board is generally known as WHITE BOARDING. More recently, teachers have started using cell phone voting systems where students can text-message their answers to the teacher or a computer system where the frequency of various answers can be rapidly tabulated for the teacher. Instead of clicking their cell phone key pads, some teachers ask students to purchase electronic personal response systems that allow them to send their answers as “votes” to the teacher’s computer. These often look like handheld television remote controls, and are called “clickers.” Because of the rapidly growing abundance of these clickers, sometimes this think-pair-share teaching strategy is more widely known specifically as using ASTRONOMY CLICKER QUESTIONS (Waller & Slater, 2011).

Going back to the steps in this think-pair-share approach, there is a third step that can often be used in this teaching strategy. It is this third step that is often the most valuable part of this teaching strategy. In the event that 40-70% of the students have the correct answer, then the teacher asks students to collaborate with another student, in a pair of two students, to discuss their answers and their rationale for why they answered the way they did. After students have had a few moments to share their answers and rationale and contemplate their partner’s answers, students are asked to vote again.  What generally occurs is that a much larger number of students, if not all, have come to the correct answer without further teacher intervention.

One might be concerned that students will “teach one another” incorrect ideas without the teacher present to monitor and correct scientific inaccuracies. Perhaps surprisingly, this intervention on the part of the teacher is rarely needed. Students generally teach each other correctly because the scientifically accurate ideas are generally easier to explain and defend than the inaccurate ideas. More importantly, students who have just recently come to understand the new ideas are better able to know which aspects of a concept are most confusing and are much better positioned to help other new learners come to know an idea than a teacher who struggled with learning the idea for the first time themselves years or even decades before. Students who are talking to other students of similar age and similar cultural backgrounds are able to use a more natural student language with analogies and metaphors that the teacher might be unable to devise to help students learn. In other words, students are well positioned to explain ideas to other students in ways that are most rapidly comprehensible.  Ongoing discussion among faculty talking about how to best use this strategy can be found over at the Turn to Your Neighbor Blog.

This CLICKER QUESTION strategy exploits and leverages this situation and has been shown to dramatically improve student learning. The reason this three-step approach is known as THINK-PAIR-SHARE is because students THINK first by themselves about a question, the PAIR collaboratively with another student to share their thinking, and finally they SHARE their answers and rationale with each other and the teacher.

Countless astronomy students are using astronomy clicker questions with varying degrees of success.  By and large, our experience is that most people who have used them, continue to use them course after course.  At the same time, talented teachers are creating their own astronomy clicker questions based on Peer Instruction.  A great 60-min YouTube video on this is available by Derek Bruff. Many astronomy clicker questions are archived and freely available at the Astronomy Faculty Lounge which can be accessed through the FACULTY LOUNGE portal at the CAPER Center for Astronomy & Physics Education Research website at (Slater & Slater, 2013).


Adams, J., & Slater, T. (2002). Learning through Sharing: Supplementing the Astronomy Lecture with Collaborative-Learning Group Activities. Journal of College Science Teaching, 31(6), 384-87.

Ausubel, D. P., Novak, J. D., & Hanesian, H. (1968). Educational psychology: A cognitive view.

Crouch, C. H., & Mazur, E. (2001). Peer instruction: Ten years of experience and results. American Journal of Physics, 69, 970.

Mazur, E., & Hilborn, R. C. (1997). Peer instruction: A user’s manual. Physics Today, 50, 68.

Mintzes, J. J. (2006). Handbook of college science teaching. National Science Teachers Assn. – featuring articles by Eric Mazur and Tim Slater

Slater, S.J., Slater, T.F. & Bailey, J.M. (2011). Discipline-Based Science Education Research: A Scientists’ Guide, 2011. W.H. Freeman Publishing and Company, New York. ISBN 1429265868.

Slater, T.F. (2008). First Steps Toward Increasing Student Engagement During Lecture. The Physics Teacher, 46(8), 554-555.

Slater, T.F. & Zeilik, M. (2003). Insights Into the Universe: Effective Ways to Teach Astronomy, American Association of Physics Teachers Press: College Park, MD (160 pages). ISBN: 1-931024-04-9

Vosniadou, S., & Ioannides, C. (1998). From conceptual development to science education: A psychological point of view. International Journal of Science Education, 20(10), 1213-1230.

Waller, W.H. & Slater, T.F. (2011) Improving Introductory Astronomy Education in American Colleges and Universities: A Review of Recent Progress. Journal of Geoscience Education, 59, 176-183.

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Would a Cognitive Scientist Recommend a Flipped Classroom? – Ramblings about Flipping the Astronomy Classroom, Over Easy

Over the years, many professors have conceded that a teacher-centered, information-download, sage-on-the-stage, lecture is probably not the best way to get introductory astronomy students excited about science.  Even when precisely illustrated, articulately delivered, and cleverly constructed, most professors realize that most students aren’t able to absorb everything that a professor could say during an hour long information-download lecture simply by listening and taking notes.

There are, of course, some brilliant and notable exceptions.  Sometimes, these folks are so good that their lectures have been video recorded and sold on DVD—I even purchased a few.  These professors are highly talented story tellers who can capture students’ attention and hold it for almost hour at a time.  Unfortunately, I’m not one of them; although I sure wish I was. And, I suspect most folks reading this aren’t either one of those either.  (Of course, far too many of us believe we’re good drivers, fantastic chefs, and great lecturers mostly because we haven’t received a statistically significant number of authoritative complaints.)

Not too many years ago, it used to be the case that when a professor earned lousy teaching evaluations from students, their Department Chair would assign that professor to go sit in on some graduate courses—not courses on how to teach, but graduate-level science courses.  The misconception was that the only way to get low teaching evaluations would be if one didn’t know the material deeply enough, to which the solution was to re-experience Jackson-level E&M lectures.

We know today that the solution to improving teaching rarely is about the teacher achieving a better understanding the concepts.  In fact, it could be far worse than this.  For instance, in K-12 mathematics, mathematics education research has clearly illustrated that the more advanced mathematics classes one takes, the lower their students’ test scores. Imagine a graph of student’s math scores plotted against the number of mathematics courses their instructor has taken.  Common sense might suggest that the result would be a monotonically increasing line with positive slope; however, perhaps surprisingly, there is a maximum inflection point given by the first derivative test and student test scores start to decline pretty rapidly the more mathematics their instructor has taken.  We’re not sure the degree to which this is true across the sciences and in astronomy in particular—anyone looking for a great research project, here you go!—but we assume it does and we have strong suspicions about why this might occur.

Allow me to digress for a moment and present some evidence from the famous Feynman Lectures on Physics at Cal Tech in the 1970s.    Nobel Laureate Richard Feynman is famous for a number of things ranging from quantum mechanics to philosophy to his work on the Manhattan Project to his gregarious personality.  If you haven’t had a chance to read Feynman’s trade books, I’d start with Surely You’re Joking; if you haven’t had a chance to listen to Feynman’s interviews, I’d start with YouTube.  There was even a movie made about his life staring Mathew Broderick, but I digress too far.  The point I’m trying to get around to make is that professors who deeply understand physics enthusiastically believe his lectures are brilliant, insightful, creative, deeply engaging and, most importantly, make physics concepts very easy to understand.  But, at the same time, undergraduates who were in that class decades about only really remember that they could barely understand what in the world Feynman might have been talking about.  It seems reasonable to assume that undergraduate physics majors at Cal Tech were mostly talented and high aptitude students—many of which went on to become professors.  Yet, they struggled to understand what the expert of experts was trying to simplify for them.  Feynman was definitely brilliant and is fun to listen to; but was he a great teacher of undergraduates?

The principle reason that deeply knowledgeable professors are in perilous danger of being lousy teachers seems to be because of fundamental differences between how novices and experts cognitively structure their understanding.  And, it isn’t just that experts know more than novices, experts really do have physically different brains!  Consider for one that novices trying to learn new concepts are not able to readily distinguish what is relevant from what is irrelevant.  For example, the common situation where an undergraduate physics student tries to memorize every single equation listed in a textbook chapter.  As experts we know this is silly because most of the textbook’s equations are simply derivations steps explaining how to get from one really important formula to another really important formula.  In the case of astronomy students, we are flustered because astronomy students don’t readily distinguish between comets and meteors or sometimes even between stars and galaxies.  This is because to novices just starting to learn astronomy, it’s all just a bunch of indistinguishable stuff that’s beyond, we'll do homework in class and you'll watch lectures at home

Another difference between novices and experts has to do with how go about approaching end-of-chapter problems. As an example from physics, consider when a professor asks a student about why they used a particular formula to answer a particular end-of-chapter homework question, students are apt to state that they used the previously listed formula for the previous homework question, so they assume that the next homework problem must use the equation following the previous one in the book. This is illustrative of novice students grabbing at every formula rather than following principles.  This happens in astronomy when students don’t seem to read the book; rather, they just flip through the pages trying to figure out where the answer is to their assigned end-of-chapter questions which, of course, are sequenced in the same sequence as the chapter!  One might wonder if it wouldn’t just be easier for students to learn the material rather than try to game the end-of-chapter questions; but one giant difference between experts and novices is that novices don’t yet have a structure to organize their thinking other than the sequence from the textbook or lecture.  Of course, the sequence presented in the textbook makes sense to use experts because it was also created by an expert.

Expert problem solvers are distinguished from novice problem solvers in that experts know how to get un-stuck.  Getting unstuck is a learned skill that comes from lots of practice working lots of problems.  Novice problem solvers will try one equation from their book to solve a problem, and if that doesn’t work, they don’t know what to do next.  It is a hard earned skill that undergraduate physics and astronomy majors learn to try to work a problem from multiple angles until they can get traction and move forward.  One reason that it is a hard earned skill is that few professors make mistakes when working problems at the front of the lecture hall, and students incorrectly assume that the best problem solves drive a straight path from question to solution with no hiccups, U-turns, or backward steps.  Few astronomy professors realize the tremendous benefits of showing their students what getting stuck and unstuck looks like.  Instead, we too often give flawless performances of problem solving or practice quiz question solving or even giving faulty essay answers on classroom activities like Lecture-Tutorials for Introductory Astronomy and, in doing so, give students the impression that successful science is a mistake-free endeavor.  All of this makes me think, oh, if my students could just appreciate the grant proposal reviews and publication referee reports I get; then they’d know science isn’t mistake-free.

As it turns out, astronomy experts aren’t automatically experts in everything—in contrast with what we often seem to believe.  Just like we can observe that novice astronomy students initially only see undifferentiated, superficial aspects to a phenomena compared to astronomy experts, we also readily see this occur with professors trying to learn how to teach astronomy better.  In recent years, our teaching excellence workshops have started to use more and more ASTRO 101 classroom videos showing students and their professors.  The challenge to using these videos in workshops is that novice professors aren’t readily able to distinguish between relevant and irrelevant aspects even when they have had decades of teaching experience—years of teaching experience doesn’t automatically correlated to levels of teaching expertise.  For example, a novice professor watching another classroom usually focuses on the preciseness of the professor’s facts being presented or the professor’s mannerisms and, occasionally the seeming chaos of the classroom during a student-activity.  Only after explicitly being highlighted repeatedly by the workshop leader, will novice professors start to move their attention from readily observable professor’s specific lecture delivery to more salient characteristics about how deeply students’ are intellectually engaged in wrestling with an new idea, the extent to which an artful professor uses complex questioning and rapid feedback to help students understand ideas more flexibly, and how the professor helps students connect complex astronomical ideas to individual experiences without asking students to memorize the professor’s personal analogies.  In other words, becoming a master teacher involves some hard work moving from being a novice to an expert too.

The bottom line here is that experts, compared to novices, know what is relevant and irrelevant about a situation.  This knowledge about relative relevance in irrelevance allows experts to chunk knowledge more efficiently than novices.  Most of us have heard that humans usually have a limit of about seven things they can mentally juggle at the same time.  Sometimes we describe that as having about seven available slots of working memory to work on solving a problem.  Compared to novices, experts don’t waste valuable and highly limited working memory slots to irrelevant aspects.  Moreover, experts are able to efficiently chunk seemingly disparate ideas together into the same working memory slot.  As a result, experts seem to be able to manage more complex thinking than novices.

Putting all of this together, experts can struggle mightily with teaching novices.  For one, professors sometimes don’t recall why they know what they know—far too many of our workshop attendees think they learned astronomy by listening to lectures and somehow seem to have forgotten all the late night group study sessions where they wrestled with complex ideas and the long problem sets they worked in undergraduate and graduate schools.   I can’t understate the surprising number of professors who believe that they learned stellar evolution only by listening to some professor in grad school lecture to them for an entire semester for two to three hours each week.  It’s a fragile perspective that can easily be undone when examined more closely; but, it’s a tacit assumption that we professors ourselves don’t often challenge without some nudging.

More than not correctly recalling why they know what they know, it has often been a while since professors themselves have struggled with the concepts they are often charged with teaching their students.  Stephen Brookfield is often quoted as saying, “The best learners … often make the worst teachers.  They are, in a very real sense, perceptually challenged.  They cannot imagine what it must be like to struggle to learn something that comes so naturally to them.”  In other words, professors don’t often recall which parts of a new concept were challenging.  This manifests itself in some subtle, but self-evident ways.  For one, we often hear from professors teaching a new course for the first time that they didn’t really understand a particular, newly encountered idea until they had to teach it; in ASTRO 101, this most often comes up when discussing how to teach seasons—a topic rarely covered in graduate school.  Getting up to speed to teach a new class for the first time reminds one of which aspects are complex and potentially troubling to students.  For another, when it has been a while since you first learned a new idea, it is likely that you have forgotten which aspects are troubling because now you have an expertly organized cognitive view of the entire landscape of the targeted concept and how it fits into the larger sequence of ideas that students are encountering.  This means, as an expert, you’re not always in the best position to help students learn a complex idea.

Wait a minute—you say—if the expert isn’t best positioned to teach students, who is?  Let me back pedal for just a moment and say, “no, my good professor, experts are indeed in a great position to teach students, as long as they are aware that they know more ideas and think about these ideas differently than novices do.”  But, there are people who are often in  a great position to help a struggling student.  These are the people that most recently learned it.  As a surprising example, consider the student in your class right now who sitting right next to a struggling student.  Because they just recently wrestled with an idea, they might be in the best position to best explain a new idea to a struggling student.

We used to think that think-pair-share, Peer Instruction, clicker-questioning techniques worked so well because students could solidify their understanding by explaining ides in the students’ own natural language instead of the scientific jargon professor’s used; instead, we now think that the reason this works is more based in cognition than language in that students can help struggling students focus on the most relevant aspects of an idea and help discard the irrelevant, so it can all be done in available working memory.

Another person who is well suited to help struggling students consider the most relevant aspects to a complex idea in the service of learning are students who learned it last term.  The use of peer-aged tutors and mentors, both outside of class time and inside of class time are demonstrating some great success in improving student learning across a wide variety of contexts.  Even graduate students are often able to help undergraduates in highly effective ways because the distance in time from when they learned ideas to now is much shorter for them than for most professors.

To take advantage of these ideas for improving student learning of complex ideas—including bridging the novice-expert barrier and providing ample opportunities to practice through conversation, problem solving, and repeated engagement with challenging ideas—a considerate professor has to think about how to set up scenarios where students are intellectually wrestling with ideas rather than just listening to someone talk about ideas from the front of the room.   This means that the role of the professor changes from being one who dispenses knowledge to one who focuses on listen to student thinking, providing rapid feedback, using individual questioning to extend student thinking into novel situations, and providing a classroom environment that is about what the students are doing, rather than about how clearly the lecturer can be seen and heard by all students simultaneously.  Working in these environments requires not a great performance lecturer; rather, these teaching environments require a professor who is an expert in the field who has rapidly accessible knowledge and can help students deepen their understanding by posing examples and counter examples of ideas to give students needed rapid feedback when they are ready for it, sometimes without warning!  Only experts in the field can do this; which is why you are the expert and tasked with teaching a particular class.

For some professors, this perspective represents a giant change in thinking amounting to nothing less than a paradigm shift of epic proportions. This dramatic shift in teaching philosophy is currently referred to as a change from a professor-centered classroom to a student-centered classroom.  And, if it really is a big, hairy deal; but it works.  The baby-steps version of this are to break lectures up with 3-minute rest breaks using Peer Instruction, think-pair-share, clicker questions where students defend their answers to one another.  Or, a bigger step is to use 10-15 minute activities to break up lecture where students wrestle with Socratic-style tutorial activities or context-rich, open-ended case study type prompts.

But, the biggest step is to flip the traditional classroom teaching model completely on its head.  In the traditional model, a professor dispenses information from the front of the room and students quietly listen and take notes before going home to do actual learning through homework assignments and study groups.  An alternative approach that goes all the way flips this to where professors task students with listening to video-lectures and reading the textbook outside of class and then reallocate valuable class time, nearly in its entirety, to students working in groups, solving problems, and doing learning tasks that in the old model would have been relegated to outside of class.  In this way, the professor can engage student thinking while they are in the active learning process, not while they are simply listening.  Such an approach puts the professor in a position to use their expertise when it is most needed; when students are struggling and actually trying to learn something.  This flipped classroom approach to course design has a solid foundation in cognitive science learning principles; but, more than that, can be a highly fulfilling endeavor for the professor who is really interested in watching and supporting student learning.

For first steps toward “flipping your classroom in astronomy,” check out the TURN TO YOUR NEIGHBOR BLOG post on how to engage in the astronomy flipped classroom.

Tim Slater, Senior Fellow at the CAPER Center for Astronomy & Physics Education Research,

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