Surveying Geology Concepts In Education Standards For A Rapidly Changing Global Context

Internationally much attention is being paid to which of a seemingly endless list of scientific concepts should be taught to schoolchildren to enable them to best participate in the global economy of the 21st Century. In regards to science education, the concepts framing the subject of geology holds exalted status as core scientific principles in the Earth and space sciences domain across the globe. Economic geology plays a critical role in the global economy, historical geology guides research into predictions related by global climate change, and environmental geology helps policy makers understand the impact of human enterprises on the land, among many other geological sciences-laden domains. Such a situation begs the question of which geology concepts are being advocated in schools. Within the U.S. where there is no nationally adopted curriculum, careful comparative analysis reveals surprisingly little consensus among policy makers and education reform advocates about which geology concepts, if any, should be included in the curriculum. This lack of consensus manifests itself in few traditional or modern geology concepts being taught to U.S. school children

iSTAR first light: Characterizing astronomy education research dissertations in the iSTAR database

There is widespread interest among discipline-based science education researchers to situate their research in the existing scholarly literature base. Unfortunately, traditional approaches to conducting a thorough literature review are unduly hindered in astronomy education research as the venues in which scholarship is reported are fragmented and widely dispersed across journals of varying disciplines. The international STudies of Astronomy education Research (iSTAR) online repository is the result of a concerted international community effort to collect and categorize existing research from peer-reviewed journal articles, dissertations/theses, and grey literature. In a “first light” survey of over 300 U.S. dissertations, we find: (i) work in AER dates back to 1923; (ii) the number of extant dissertations is far greater than anticipated; (iii) research methods definitions have evolved; and (iv) most work has studied participants’ broad knowledge rather than specific learning targets. The surprisingly wide breadth of rarely cited research motivates us to collect more AER from across international and cross-disciplinary sources

WFPC2 Observations of the Hubble Deep Field-South

The Hubble Deep Field-South observations targeted a high-galactic-latitude field near QSO J2233-606. We present WFPC2 observations of the field in four wide bandpasses centered at roughly 300, 450, 606, and 814 nm. Observations, data reduction procedures, and noise properties of the final images are discussed in detail. A catalog of sources is presented, and the number counts and color distributions of the galaxies are compared to a new catalog of the HDF-N that has been constructed in an identical manner. The two fields are qualitatively similar, with the galaxy number counts for the two fields agreeing to within 20%. The HDF-S has more candidate Lyman-break galaxies at z > 2 than the HDF-N. The star-formation rate per unit volume computed from the HDF-S, based on the UV luminosity of high-redshift candidates, is a factor of 1.9 higher than from the HDF-N at z ~ 2.7, and a factor of 1.3 higher at z ~ 4.Comment: 93 pages, 25 figures; contains very long table

Bar Evolution Over the Last Eight Billion Years: A Constant Fraction of Strong Bars in GEMS

One third of present-day spirals host optically visible strong bars that drive their dynamical evolution. However, the fundamental question of how bars evolve over cosmological times has yet to be addressed, and even the frequency of bars at intermediate redshifts remains controversial. We investigate the frequency of bars out to z~1.0 drawing on a sample of 1590 galaxies from the GEMS survey, which provides morphologies from HST ACS two-color images, and highly accurate redshifts from the COMBO-17 survey. We identify spiral galaxies using the Sersic index, concentration parameter, and rest-frame color. We characterize bars and disks by fitting ellipses to F606W and F850LP images, taking advantage of the two bands to minimize bandpass shifting. We exclude highly inclined (i>60 deg) galaxies to ensure reliable morphological classifications, and apply completeness cuts of M_v <= -19.3 and -20.6. More than 40% of the bars that we detect have semi major axes a<0.5" and would be easily missed in earlier surveys without the small PSF of ACS. The bars that we can reliably detect are fairly strong (with ellipticities e>=0.4) and have a in the range ~1.2-13 kpc. We find that the optical fraction of such strong bars remains at ~(30% +- 6%) from the present-day out to look-back times of 2-6 Gyr (z~0.2-0.7) and 6-8 Gyr (z~0.7-1.0); it certainly shows no sign of a drastic decline at z>0.7. Our findings of a large and similar bar fraction at these three epochs favor scenarios in which cold gravitationally unstable disks are already in place by z~1, and where on average bars have a long lifetime (well above 2 Gyr). The distributions of structural bar properties in the two slices are, however, not statistically identical and therefore allow for the possibility that the bar strengths and sizes may evolve over time.Comment: Accepted by ApJ Letters, to appear in Nov 2004 issue. Minor revisions,updated reference

The Hubble Deep Field South Flanking Fields

As part of the Hubble Deep Field South program, a set of shorter 2-orbit observations were obtained of the area adjacent to the deep fields. The WFPC2 flanking fields cover a contiguous solid angle of 48 square arcminutes. Parallel observations with the STIS and NICMOS instruments produce a patchwork of additional fields with optical and near-infrared (1.6 micron) response. Deeper parallel exposures with WFPC2 and NICMOS were obtained when STIS observed the NICMOS deep field. These deeper fields are offset from the rest, and an extended low surface brightness object is visible in the deeper WFPC2 flanking field. In this data paper, which serves as an archival record of the project, we discuss the observations and data reduction, and present SExtractor source catalogs and number counts derived from the data. Number counts are broadly consistent with previous surveys from both ground and space. Among other things, these flanking field observations are useful for defining slit masks for spectroscopic follow-up over a wider area around the deep fields, for studying large-scale structure that extends beyond the deep fields, for future supernova searches, and for number counts and morphological studies, but their ultimate utility will be defined by the astronomical community.Comment: 46 pages, 15 figures. Images and full catalogs available via the HDF-S at http://www.stsci.edu/ftp/science/hdfsouth/hdfs.html at present. The paper is accepted for the February 2003 Astronomical Journal. Full versions of the catalogs will also be available on-line from AJ after publicatio

The Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry

The Hubble Deep Field (HDF) is a Director's Discretionary program on HST in Cycle 5 to image an undistinguished field at high Galactic latitude in four passbands as deeply as reasonably possible. These images provide the most detailed view to date of distant field galaxies and are likely to be important for a wide range of studies in galaxy evolution and cosmology. In order to optimize observing in the time available, a field in the northern continuous viewing zone was selected and images were taken for ten consecutive days, or approximately 150 orbits. Shorter 1-2 orbit images were obtained of the fields immediately adjacent to the primary HDF in order to facilitate spectroscopic follow-up by ground-based telescopes. The observations were made from 18 to 30 December 1995, and both raw and reduced data have been put in the public domain as a community service. We present a summary of the criteria for selecting the field, the rationale behind the filter selection and observing times in each band, and the strategies for planning the observations to maximize the exposure time while avoiding earth-scattered light. Data reduction procedures are outlined, and images of the combined frames in each band are presented. Objects detected in these images are listed in a catalog with their basic photometric parameters.Comment: 37 pages, XX PostScript figures, uses aaspp4.sty astrobib.sty. (Astrobib is available from http://www.stsci.edu/software/TeX.html .) To appear the Astronomical Journal. More info on the Hubble deep field can be found at http://www.stsci.edu/../ftp/observer/hdf/hdf.html . More figures (images) can be found at http://www.stsci.edu/../ftp/observer/hdf/references/williams/ and the full source catalog is available at http://www.stsci.edu/../ftp/observer/hdf/archive/v2catalog

Establishing the Empirical Relationship between Non-science Majoring Undergraduate Learners’ Spatial Thinking Skills and Their Conceptual Astronomy Knowledge

The science education community has long tacitly assumed that astronomy, in addition to other fields in the earth and space sciences, is a conceptual domain crucially dependent upon threedimensional representations and thinking, and that learners need to utilize complex spatial thinking to develop deep understanding of the field. However, a review of the literature indicates that the astronomy education research community has yet to empirically establish the character of the relationship between students’ spatial reasoning ability and their ability to learn astronomy content in college science classes in general, or the manner in which this relationship varies across the astronomy content domain. In order to determine the relationship between students’ spatial reasoning skills and their ability to learn astronomy content, undergraduate students in a non-major introductory astronomy survey class at a medium-sized, research-extensive midwestern university were given astronomy knowledge diagnostics at the beginning and end of a semester-long introductory astronomy survey course, as well as spatial reasoning diagnostics in the middle of the semester (N = 86, 49 males, 37 females). All data were matched. Instruments used were the Test of Astronomy STandards (TOAST), a test of conceptual astronomy content knowledge, and What Do You Know? (WDYK), a test of students’ understanding of astronomical geography, events related to Earth’s rotation, and phenomena related to Earth’s orbit and tilt. Spatial reasoning ability was measured with a three-part instrument designed to determine students’ ability to perform mental rotations, transformations, and spatial self-efficacy. In addition, at the end of the semester 14 students were interviewed to explore and validate assumed thinking processes used during the assessments. Pearson r correlations were performed in order to explore potential relationships among incoming prior knowledge, knowledge after instruction, knowledge gains and students’ spatial reasoning related to mental rotations, transformations, and self-efficacy. After receiving traditional lecture-based instruction, it was found that students’ normalized gains for astronomy content knowledge were quite low (TOAST, = 0.26; WDYK, = 0.13). As a result of the small variation in gain score, the correlations between the gains and the spatial assessments turned out to be quite small. In contrast, the Pearson r correlations between astronomy pre- and post-course scores for the TOAST and WDYK tests, and two of the three components of the spatial assessment instrument show moderate to strong relationships. We observed strong and statistically significant relationships between the TOAST pre-test and spatial rotation score (r(84) = .40, p<.01), the TOAST pre-test and spatial transformation score (r(84) = .36, p <. 01), the TOAST post-test and spatial rotation score (r(84) = .48, p < .01), the TOAST post-test and spatial transformation score (r(84) = .37, p < .01), the WDYK pre-course and spatial rotation score (r(84) = .31, p < .01), the WDYK precourse and spatial transformation score (r(84) = .19, p < .05), the WDYK post- course and spatial rotation score (r(84) = .43, p < .01), and the WDYK post- course and spatial transformation score (r(84) = .36, p < .01). Taken together, spatial reasoning appears to be moderately to strongly related to astronomy knowledge, and rotation skills appear to be more dominant than transformation skills for astronomy. The correlation between astronomy post-course scores and spatial scores suggests that the relationship between spatial reasoning and astronomy ability explains about 25% of the variation in the data. We further disaggregated our data by gender and found moderate gender differences in some spatial reasoning scores, however, not always in the same direction. This data invites further investigation in a number of aspects, particularly a comparison with courses showing higher gains, and a more in-depth investigation of the observed gender differences. Our findings result in recommendations for astronomy instructors to recognize the need to support student learning by employing instructional techniques that support and scaffold student thinking related to astronomy concepts demonstrated to rely heavily on spatial reasoning. This work was supported, in part, by the Wyoming Excellence in Higher Education Endowment

Reformperspektiven und die Mühen der Ebene. Beispiel Berlin

"Es genügt nicht, als Schulminister richtige Reformideen zu haben und schön klingende Leitbilder entwerfen zu lassen, man muss auch dafür sorgen, dass die in den Schulen tätigen Menschen die für die Bildung der Kinder wichtigen Reformen ,flächendeckend\u27 in Alltagspraxis umsetzen können." Mit dieser Feststellung bewerten die Autoren von der Landesgruppe Berlin, welche Leitbilder für Ganztagsschulen vorgegeben werden und woran deren Umsetzung hapert. Der Beitrag aus Berlin ist exemplarisch für das Dilemma, in das Schulen geraten, wenn zu den guten Absichten nicht die passenden Rahmenbedingungen geschaffen werden