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					Creating a consensus of what “should” be taught in introductory astronomy courses:

Stephanie Slater, Ph.D.

(part of a paper that is from a group)

1.   INTRODUCTION

One of the most oft quoted exchanges from the story of Alice in Wonderland can be unceremoniously
summarized as “it doesn’t much matter which way you go, if you don’t know where you are going.” In
the context of teaching astronomy, it is extraordinarily difficult for even the most conscientious
astronomy professor to make informed decisions about how to design, deliver, assess and improve
teaching if they have not clearly and explicitly established learning goals. Brissenden, Matheiu, and
Slater (2001?) propose that setting clear course learning goals is the most important decision an
astronomy professor can make when designing a course--a decision that is apparently not often done
explicitly. To make matters worse, Slater, Adams, Brissenden, and Duncan (2001?) convincingly
demonstrated that it was incredibly difficult to infer the learning goals of most astronomy courses are by
surveying ASTRO 101 undergraduate course syllabi. This begs the question, what should astronomy
professors tell their students about the learning goals of introductory astronomy and how might one assess
if students have adequately achieved such goals?

One might be initially inclined to think that the authoritative wisdom revealed by surveying the
exhaustive tables of contents for a collection of the most popular and peer-reviewed ASTRO 101
textbooks. Unfortunately, the extensive topic ranges contemporary textbooks include is mostly indicative
of the range and domain of possible topics an instructor might wish to select from rather than entirely
cover during a class. In other words, a textbook’s table of contents doesn’t reflect a pragmatic set of
learning goals for a course in and of themselves. In recent years, several groups of astronomers have
dedicated considerable effort and tried to come to consensus on what the essential astronomy concepts are
and, fortunately, there are broad areas of overlap among the groups. This is described in more detail
below.

At the same time, astronomy education researchers are becoming increasingly more sophisticated in the
research agenda they are pursuing (Slater, 2008). Much of today’s research effort is driven by a
convergence of educational research on how people learn that consistently and resoundingly supports a
central theme – students bring prior knowledge and beliefs to a learning experience that are well poised to
interfere. This supports an old teaching idea that the most effective and time-tested pedagogical approach
is to ascertain what the learner knows and teach them accordingly (Ausbel, 1967?). Several assessment
instruments have been created in the past decade, the Astronomy Diagnostic Test2-(ADT2) most notable
and widely used among them, but these were created without the benefit of explicit learning goals
established by the broader community of astronomy educators which now exists.

Taken together, a significant need presents itself. First, there is a need to establish a clear consensus of
astronomy teaching goals among professionals. Second, there is a need to efficiently assess students’ pre-
course and post-course knowledge state relative to these goals. In response, astronomy educators in the
Cognition in Astronomy, Physics, and Earth sciences Research (CAPER) Team have created a is a valid,
reliable, and easy-to-use pre/post assessment instrument that adequately reflects the consensus goals of a
broad community of astronomy educators. This paper is the first of three papers which describe and
document the development and validation of such an assessment instrument, in the critically important
context of designing a process to establish the consensus astronomy learning goals of our broad
community of astronomy educators. The focus of this paper is the construction of a consensus document
proposing a



2. A Consensus of the Experts



Common experience suggests that it is nearly impossible to get any two experienced instructors of
astronomy to come to perfect agreement with regard to the “correct” content of an introductory astronomy
survey course. (We include ourselves in this statement; in the fine details there is a great deal to disagree
about.) Marrying the published positions of the NRC, AAAS and AAS allowed us to move past
individual opinion and ground our assessment in the collective wisdom of the many. Pragmatically, we
could never hope to match the intellectual energy, time, or resources that these groups have invested in
determining the content central to astronomy as a discipline. We reasoned that if we tried to marry the
work of the NRC, the AAAS, and the AAS that we would find recurring themes; we would determine
those items to be essential learnings in astronomy. We would also find standards, benchmarks, and goals
that did not show up repeatedly; in the same spirit we would set these items to the side as optional, rather
than essential learnings.

As we worked through the process of correlating the standards, we realized that this was a process of
compromise and judgment calls, largely due to the different approaches that these three organizations
used in the construction of their documents. The AAS was written in broad strokes, making it ideal for
organizing the NSES and more detailed AAAS documents. Occasionally an individual AAAS
benchmark contained multiple ideas. In those instances we separated the benchmark into smaller, one-
idea units similar to the approach taken by in an earlier analysis of the benchmarks (Slater 2001). In other
instances we found that the AAAS document contained redundancies, due in part to its multiple grade-
level approach, which we eliminated from the process. The AAS goals included science process skills
and goals related to understanding the nature of science, but did not emphasize technology or historical
information, while the AAAS benchmarks included a good deal of historical information, and a focus on
technologies used in astronomy. The moderately detailed NSES do not focus on the history of astronomy
but addresses science process skills and the uses of technology in separate portions of the document.
Because we were most interested in developing the TOAST Survey to assess content knowledge, we
deliberately set aside the benchmarks and goals related to historical information, technology and process
skills.

Once we determined the goals, standards and benchmarks (hereafter referred to as “criteria”) to be
included, we engaged in a reiterative, inductive card sorting approach. Lacking preconceptions about
what the final product would look like, we printed the goals out, cut them apart into individual criteria,
and began to rearrange them until the layout made sense. The objective was to honor the work done all
three groups, striving to find commonalities wherever possible. Content was included or eliminated as
described previously, with one exception. Scale, or “a broad understanding on the scope” of the Universe
was unique to the goals set forth by the AAS. The decision was made to retain the idea of scale in our
consensus document as it represents a concept that is critical, and perhaps unique, to astronomy.

The consensus document was submitted to our group of experts for inspection. The group of experts
included research astronomers, Astro 101 instructors and active members of the astronomy education
community. The experts were associated with astronomy research institutions, research and liberals arts
universities, and community colleges nationwide. Rather than focusing on the content validity of the
criteria which had been soundly argued for by the experts of the NRC, AAAS and AAS, the experts were
asked to focus on the degree to which the criteria had been correlated in a logical manner. Given that a
certain amount of subjectivity is inherent in this type of document, experts’ feedback was analyzed to
determine the presence of significant errors, as determined by either strong objections to aspects of the
correlation, or by the occurrence of similar changes suggested by multiple experts. No expert expressed
major concerns and there were no instances of repeated suggestions. In every case, the final consensus
was deemed to be a reasonable compromise between the source documents.

The final consensus consists of three meta-concepts: physical laws and processes, the structure and
evolution of the universe, and patterns in the sky. Within these meta-concepts there were eleven criteria.
The consensus document is included in Table 2 (Appendix A). The argreement between the three source
documents is detailed in Table 3 (Appendix A).
Appendix A: The Consensus Document




Table 2: Meta-criteria, Criteria and TOAST Survey Items



Meta-Criteria                         Criteria                          TOAST Survey Items

Physical Laws and Processes           Gravity                           Questions 20, 21

                                      EMR & EMR production              Questions 23,25,26,27

                                      Fusion & the formation of         Questions 8, 22, 24
                                      heavy elements

The Structure and Evolution           The Evolution of the universe     Questions 9, 15
of the Universe
                                      Star and stellar evolution        Questions 13, 14, 16, 17

                                      The evolution and structure of    Questions 18, 19
                                      the solar system

                                      Seasons                           Questions 7, 12

                                      Scale                             Questions 10, 11

Patterns in the Sky                   Yearly patterns                   Questions 2, 4

                                      Daily patterns                    Questions 1, 6

                                      Moon phases                       Questions 3, 5




Table 3: Agreements among three course documents

    AAS Goals for Astro 101            NSES Astronomy Related                    AAAS Astronomy Related
                                             Standards                                  Standards

Physical Laws and Processes

     An understanding of a       Ideas related to gravity:             Ideas related to gravity:
      limited number of crucial
      astronomical quantities,       Gravity is the force that keeps      The Sun’s gravitational pull holds the
    together with some             planets in orbit around the Sun          Earth and other planets in their orbits,
    knowledge of physical          and governs the rest of the              just as the planets’ gravitational pull
    laws                           motion in the Solar System.              keeps their moons in orbit around
   The notion that physical       Gravity alone holds us to the            them. (4G)
    laws and processes are         Earth's surface                         Everything on or anywhere near Earth
    universal.                    Gravitation is a universal force         is pulled toward the planet’s center by
   Some knowledge of              that each mass exerts on any             gravitational force. (4B)
    related subjects (e.g.,        other mass. The strength of the
    gravity and spectra from       gravitational attractive force
    physics) and a set of          between two masses is
    useful “tools” from            proportional to the masses and
    related subjects such as       inversely proportional to the
    mathematics.                   square of the distance between
                                   them.

                               Ideas related to EMR production:

                                  Light interacts with matter by
                                   transmission (including
                                   refraction), absorption, or          Ideas related to EMR production:
                                   scattering (including reflection).
                                   To see an object, light from that       Human eyes respond to only a narrow
                                   object--emitted by or scattered          range of wavelengths of
                                   from it--must enter the eye.             electromagnetic radiation—visible
                                  Electromagnetic waves result             light. Differences of wavelength within
                                   when a charged object is                 that range are perceived as differences
                                   accelerated or decelerated.              in color. (4F)
                                   Electromagnetic waves include           Various accelerating electric charges
                                   the electromagnetic spectrum             produce a large variety of
                                   from radio waves to gamma                electromagnetic waves. These vary
                                   rays. The energy of                      from radio waves, the longest, to
                                   electromagnetic waves is carried         gamma rays, the shortest. In empty
                                   in packets whose magnitude is            space, all electromagnetic waves move
                                   inversely proportional to the            at the same speed—the “speed of
                                   wavelength.                              light.” (4F)
                                  Each kind of atom or molecule           The observed wavelength of a wave
                                   can gain or lose energy only in          depends upon the relative motion of
                                   particular discrete amounts and          the source and the observer (Doppler
                                   thus can absorb and emit light           effect). Because the light seen
                                   only at wavelengths                      from almost all distant galaxies has
                                   corresponding to these amounts.          longer wavelengths than comparable
                                   These wavelengths can be used            light on Earth, astronomers believe that
                                   to identify the substance.               the whole universe is expanding. (4F)

                               Ideas related to fusion:

                                  Stars produce energy from
                                   nuclear reactions, primarily the
                                   fusion of hydrogen to form
                                   helium. These and other
                                   processes in stars have led to the
                                   formation of all the other           Ideas related to fusion:
                                   elements.
                                  Fusion is the joining of two            Stars condensed by gravity out of
                                   nuclei at extremely high                 clouds of molecules of the lightest
                                  temperature and pressure, and is        elements until nuclear fusion of
                                  the process responsible for the         the light elements into heavier ones
                                  energy of the sun and other             began to occur. (4A)
                                  stars.


The Structure and Evolution
of the Universe
                              The evolution of the universe           The evolution of the universe
   A cosmic perspective--a
    broad understanding of       The origin of the universe             On the basis of scientific evidence, the
    the nature, scope and         remains one of the greatest             universe is estimated to be over 10
    evolution of the              questions in science. The "big          billion years old. The current theory is
    Universe, and where the       bang" theory places the origin          that its entire contents
    Earth and Solar System        between 10 and 20 billion years         expanded explosively from a hot,
    fit in.                       ago, when the universe began in         dense, chaotic mass. Eventually, some
   An understanding of the       a hot dense state; according to         stars exploded, producing clouds of
    evolution of physical         this theory, the universe has           heavy elements from which other stars
    systems.                      been expanding ever since.              and planets could later condense in a
                                 Early in the history of the             process that is ongoing. (4A)
                                  universe, matter, primarily the        Because the light seen from almost all
                                  light atoms hydrogen and                distant galaxies has longer
                                  helium, clumped together by             wavelengths than comparable light on
                                  gravitational attraction to form        Earth, astronomers believe the whole
                                  countless trillions of stars.           universe is expanding. (4F)


                              Stars and stellar evolution

                                 Billions of galaxies, each of       Stars and stellar evolution
                                  which is a gravitationally bound
                                  cluster of billions of stars, now      There are more stars in the sky than
                                  form most of the visible mass in        anyone can easily count. (4A)
                                  the universe.                          Stars differ from each other in size,
                                                                          temperature, and age, and behave
                                                                          according to the same
                                                                          physical principles observed on Earth.
                                                                          Unlike the Sun, most stars are in
                                                                          systems of two or more stars orbiting
                                                                          around one another. (4A)
                                                                         Stars are like the Sun, some being
                                                                          smaller and some larger, but they are
                                                                          so far away that they look like points
                                                                          of light. (4A)
                                                                         The Sun is a medium-sized star located
                                                                          near the edge of a disk-shaped galaxy
                                                                          of stars. The universe contains many
                                                                          billions of galaxies, and each galaxy
                                                                          contains many billions of stars. (4A)
                                                                         The Sun is many thousands of times
                                                                          closer to Earth than any other star.
                                                                          Light from the Sun takes only a few
                                                                          minutes to reach Earth, but light
                                                                          from the next nearest star takes a few
                                                                          years to arrive. Some distant galaxies
                                            are so far away that their light takes
                                            several billion years to reach
                                            Earth. People on Earth, therefore, see
                                            the stars as they were that long ago in
                                            the past. (4A)


                                        The evolution and structure of the solar
                                        system

                                           Nine planets of very different sizes,
                                            composition, and surface features
                                            move around the Sun in nearly circular
                                            orbits. Several planets have a
                                            great variety of moons, some of which
                                            show evidence of geological activity.
The evolution and structure of the          (4A)
solar system                               Many chunks of rock orbit the Sun.
                                            Some meet the Earth in its yearly orbit
   The sun, the earth, and the rest        around the Sun [meteors] while others
    of the solar system formed from         are mixed with ice and have orbits that
    a nebular cloud of dust and gas         carry them close to the Sun
    4.6 billion years ago. The early        [comets], where the Sun’s radiation
    earth was very different from the       boils off frozen material from their
    planet we live on today.                surfaces and pushes it into a long,
   The Earth is the third planet           illuminated tail. (4A)
    from the Sun in a system that          Earth is a relatively small planet, third
    includes the Moon, the Sun,             from the Sun, and composed mostly of
    eight other planets and their           rock. Other planets have compositions
    moons, and smaller objects, such        and conditions very different from
    as asteroids and comets. The            Earth’s. (4B)
    Sun, an average star, is the           The Earth is one of several planets that
    central and largest body in the         orbit the Sun, and the Moon orbits
    Solar System.                           around the Earth. Like all planets and
                                            stars, the Earth is
                                            approximately spherical in shape. (4B)


                                        The Sun and Earth’s seasons

                                           The Sun warms the land, air, and
                                            water. (4E)
                                           Because the Earth turns daily on an
                                            axis that is tilted relative to the plane
                                            of its yearly orbit around the Sun,
                                            sunlight falls more intensely
                                            on different parts of the planet during
                                            the year. The difference in heating of
                                            the Earth’s surface produces the
                                            planet’s seasons and weather patterns.
The Sun and Earth’s seasons                 (4B)

   The Sun provides the light and
    heat necessary to maintain the
    temperature of the Earth.
                                 The Sun is the major source of
                                  energy for phenomena on the
                                  Earth's surface. Seasons result
                                  from variations in the amount of
                                  the Sun's energy hitting the
                                  surface due to the tilt of the
                                  Earth's rotation on its axis and
                                  the length of the day.
Patterns in the sky           Yearly patterns, daily patterns and    Yearly patterns, daily patterns and moon
                              moon phases                            phases
   Familiarity with the
    night sky and how its        The Sun, Moon, stars, clouds,         The patterns of stars stay the same
    appearance changes with       birds, and airplanes all have          although they appear to move across
    time and position on          properties, locations, and             the sky nightly, and different stars can
    earth.                        movements that can be observed         be seen during different
                                  and described.                         seasons. Planets change their positions
                                 Objects in the sky have patterns       against the background of stars. (4A)
                                  of movement. The Sun, for             The rotation of the Earth on its axis
                                  example, appears to move across        every 24 hours produces the night-and-
                                  the sky in the same way every          day cycle. (4B)
                                  day, but its path changes slowly      The Moon’s orbit around Earth (once
                                  over the seasons. The Moon             about every 28 days) determines what
                                  moves across the sky on a daily        part of the Moon is lit by the Sun and
                                  basis much like the Sun. The           how much of that part can be
                                  observable shape of the Moon           seen from Earth. We see these changes
                                  changes from day to day in a           as phases of the Moon. (4B)
                                  cycle that lasts about a month.       The Sun can be seen only in the
                                 Most objects in the Solar System       daytime, but the Moon can be seen
                                  are in regular and predictable         sometimes at night and
                                  motion. Those motions explain          sometimes during the day. All sky
                                  such phenomena as the day, the         objects appear to move slowly across
                                  year, the phases of the Moon,          the sky. The Moon looks a little
                                  and eclipses.                          different every day, but looks the same
                                                                         again about every four weeks. (4A)

				
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