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It is a sad fact, or perhaps a happy one, that many geoscientists in academia will find themselves in front of a classroom of 100–300 undergraduate nonscience majors, lecturing to them for three hours per week. Whether it is ‘Rocks for Jocks’ or ‘Waves for Babes,’ students often are under the impres-sion that geoscience classes will be the least painful way to fulfill their science credit requirements. The sense of personal ano-nymity that can accompany large-enrollment classes often results in a different level of student engagement compared with smaller classes. Thus, if students are physically pres-ent at all, instructors often have only their much-divided attention. How can professors keep 300 students, even the ones in the back of the classroom who are barely visi-ble, awake and engaged?

This article presents results from a trial experience at the University of Florida, Gainesville, of an educational software sys-tem that claims to increase teacher-student interactivity, and thus the attentiveness of each individual student. Several such sys-tems, which are referred to here as student response systems (SRS), exist in the market today. The technology allows an instructor to pose a question to the whole class, and allows the students to register their answers using a remote control transmitter with a numerical (and in some cases alphanu-meric) keypad. Responses are automatically tabulated, can be immediately displayed in a graphical format, and are recorded for use in grading, assessment, attendance, and other pedagogical strategies. With a focus on Earth sciences, the following outlines meth-ods of use, and both the benefits and draw-backs that have been experienced with this new teaching technology.

Choosing and Using SRS Technology

Because Earth science instructors com-monly teach large-enrollment general edu-cation classes, publishers seeking to have their textbooks ‘adopted’ have long courted them. Over the years, publishers have tried to make their increasingly similar textbooks more attractive with such add-ons as exam test banks, Web links, and various multime-dia supplements. The SRS software and accompanying interactive content material is the latest addition in that vein. Early mar-keting strategies for these products have been targeted at individual faculty through publishers, with publishers often providing the classroom hardware and software at no cost and students purchasing remote trans-mitters for about US$30 (~US$15 if bundled with the publisher’s textbook). This model led to a variety of different systems being used on campus, prompting the University of Florida to adopt a single system campus-wide.

While not intending to endorse any par-ticular product available on the market, the SRS system reviewed here is one that is highly compatible with Microsoft Power-point. With testing now in its fourth semes-ter of classroom trial at the University of Florida, instructors independently have set-tled on similar pedagogical strategies. While the system certainly can be used to expe-dite the administration and grading of quiz-zes and exercises, some instructors have chosen to incorporate the SRS into the daily lecture. Typically, one to four interactive slides are incorporated into each one-hour PowerPoint® presentation. Questions range in complexity from almost the level of ‘what did I just say?’ to more complicated synthe-sis questions. Often, these questions pur-posefully are very similar to questions that

may appear on exams, so that students become familiar with the instructor’s style of assessment and expectations. Partial credit (e.g., 2 out of 3 points) is awarded for simply participating and submitting an answer, but full credit requires a correct answer. This grading scheme provides ample incentive for students to try to answer cor-rectly, while not inflicting the stress of being in a constant testing environment. Obviously, there is no need to take attendance with this system, as absentees receive no points.

For a working example, take the familiar topic of plate boundaries. After explaining the various plate boundary types in a series of PowerPoint slides, some students will be riveted while others drift off. Suddenly, a question appears in bold letters: The East African Rift Valley is associated with a (1) divergent boundary, (2) convergent boundary, (3) shear boundary, (4) hot spot, (5) not at a plate boundary. As soon as the ‘question slide’ appears (Figure 1, top), stu-dents sit up. Students start looking back over their notes, conferring with their neighbors, and in some cases making calculations or drawing pictures. Just like that, they have switched from passive to active learning mode.

After the counter (at the bottom left of the slide) indicates that most students have transmitted their answers, a countdown timer (set to 10 seconds) is engaged and displayed on the slide. After time has elapsed, the system accepts no more answers. A light on the students’ transmitters indicates to them that their responses have been received; or, to reassure the students further, the instructor can display a grid indicating which students have answered. With the next keystroke, class responses are tabulated and presented as a bar graph or pie chart and the correct answer is indicated (Figure 1, bottom). The class emits exclamations of joy or remorse, and the opportunity now presents itself to reiterate or elaborate on the features of divergent boundaries, depend-ing upon the results. Students, especially those registering incorrect answers, have heightened interested in the explanation. They have become aware of the kind of question that the instructor expects them to be able to answer and of their ability, or lack thereof, to do so, while still preserving their anonymity among their peers (but not the instructor).

Classroom Benefits

An informal poll, conducted in December 2005 in a University of Florida “Introduction to Oceanography” geoscience class that used SRS, revealed that 80–90% of the stu-dents found that the SRS enhanced their understanding and active learning and caused them to pay closer attention in class and attend class more regularly (agree and strongly agree in Table 1). Sixty-seven per-cent of the students approved of the system overall, while about 10% seemed to have negative impressions. There was no correla-tion between positive feelings about SRS and either points scored during class ques-tions or performance on class exams.

From these results, it can be concluded that the self-perceived benefits of the system cut across the normal ‘front of the classroom’/’back of the classroom’ divide. This connec-tion with the lower-performing portion of the class is exactly the effect desired. The average class score on exams has increased from previous years, though without a con-trol group the claim that SRS technology has improved grades is not statistically defensible.

This technology has been used to several pedagogic ends, and many qualitative benefits have been observed. SRS systems encourage,

even force, active engagement in daily class. Use of interactive technology breaks up and punctuates the metronomic and one-direc-tional flow of information often associated with PowerPoint presentations. It enables frequent real-time assessment of student understanding and encourages attendance and more continual study patterns. But per-haps most gratifying, it initiates discussion and establishes a greater sense of inclusion and self-responsibility in learning within each student.

A number of characteristics of the geosci-ences make SRS particularly useful in edu-cational activities. One stems from the fact that because Earth science is so visually ori-ented, it has become very common to use slide presentation systems such as Power-Point to create image-rich lectures. Integra-tion with multimedia presentation software like PowerPoint enables one to use plat-forms such as video and animation that help to illustrate processes occurring at a variety of temporal and spatial scales and concepts that are extremely difficult to grasp for most students. Often, the processes depicted by the images shown seem obvi-ous to scientists, but for the nonscientist this is often not the case. Use of an SRS allows each student to observe, contemplate, and respond, enabling the instructor to keep a finger on the students’ pulse of understanding.

In general education Earth science classes, instructors attempt to create an understanding of the Earth system in scien-tifically subliterate students by introducing a progressive sequence of concepts from the

physical, chemical, and biological sciences. Each additional step requires a mastery of a set of principles and terms. The frequent assessment facilitated by SRS systems enables an instructor to know that the stu-dents as a whole are up to speed and ready to move forward, and for the students to be made aware of the areas that will require of them additional study.

Difficulties Experienced

The biggest downsides identified by students in the survey (Table 1) were technical diffi-culties and cost. In the first year, problems

Engaging Today’s Students in Earth Science 101

Fig. 1. (top) Example of a PowerPoint/response system question slide. (bottom) Question slide with class responses tabulated.

By a. r. ZiMMerMan and M. C. SMitH

Table 1. A Survey of 130 Students (of 155 Registered Students) in Introduction to Oceanography on a Random Midterm Daya

Strongly Agree

Agree Neutral Disagree Strongly Disagree

The automated response system:Helps me test my understanding of the material in real time. 24 56 11 5 4

Makes me pay closer attention during lecture. 22 53 18 5 2

Makes me be a more active learner during class. 16 47 27 6 4

Encourages me to attend lectures. 70 26 3 0 2

Makes class more fun and a better learning environment 10 36 30 10 14

Cost ($15–30) of the transmitter is worth the benefit it brings to class 5 19 30 27 19

Technological difficulties make this tool more burdensome than useful.

9 20 34 32 5

I approve of the use of the response system in this class. 21 47 22 5 6aValues given in percent.

Students cont. on page 344

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POSITIONS AVAILABLE

Atmospheric Sciences

Aeronomy Program, National Science Foundation, Division of Atmospheric Sciences. The National Science Foundation is seeking qualified candi-dates for the position of Program Director for the Aeronomy Program, Upper Atmosphere Research Section, Division of Atmospheric Sciences (ATM), Directorate for Geosciences (GEO), Arlington, VA.

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Appointment to these positions may be on a one or two year Visiting Scientist appointment or a Federal Temporary appointment. Alternatively, these positions may be filled under the terms of the Intergovernmental Personnel Act. Applicants must possess a Ph.D. or equivalent experience in aeronomy, space physics, or upper atmospheric science or a related discipline. In addition, six or more years of successful research, research administration, and/or managerial experience pertinent to the program is required.

Announcement E20060116-Rotator, with posi-tion requirements and application procedures may be found on the NSF’s Division of Human Resource Management website at http://www.nsf.gov/about/career_opps/. Applications must be received by September 25, 2006.

NSF is an Equal Opportunity Employer Com-mitted to Employing a Highly Qualified Staff That Reflects the Diversity of Our Nation.

Postdoctoral Research Position at Dalhousie University. The Department of Physics and Atmo-spheric Science at Dalhousie University invites applicants for a postdoctoral research position to work with Ian Folkins and Randall Martin on the physics and chemistry of the Tropical Tropopause Layer in the Canadian Middle Atmosphere Model. Interest in tropical convection and experience in programming are required. Experience with global models desireable. All interested, qualified persons are encouraged to apply via e-mail, by sending a letter of application, list of three refer-ences, and curriculum vitae to Prof. Ian Folkins (ian.folkins@dal.ca). The position will remain open until filled.

Biogeosciences

Ecosystem Biogeochemical Modeler. The Col-lege of Agricultural and Environmental Sciences, University of California, Davis invites applications for a position at the tenure-track assistant professor level, with the possibility of an appointment in the California Agricultural Experiment Station. We are interested in an ecosystem biogeochemi-cal modeler who has strong skills and interests in understanding and forecasting ecosystem dynam-ics in the context of global and regional environ-mental change. The scientist in this position will develop and validate models addressing effects of global and regional changes in sources, transport, transformation, and deposition of biologically important elements on terrestrial and aquatic eco-systems, with a non-exclusive focus on California ecosystems. The successful candidate will estab-lish an outstanding nationally and internationally recognized research program that addresses both fundamental and applied questions in ecosystem biogeochemistry. The research program should combine multi-scale biogeochemical modeling with use of existing large-scale manipulations or anthropogenic disturbances such as water trans-fers, nitrogen deposition, or ecosystem shifts due to biological invasions or climate change. This position requires cross-disciplinary research in global environmental change and conservation biology. A Ph.D. in biogeochemistry with modeling emphasis or in a related discipline is required by

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Geomicrobiology/Microbial Biogeochemistry Faculty Position, Geological Sciences, University of Michigan. The Department of Geological Sci-ences at the University of Michigan anticipates filling a tenure-track position for a geomicrobi-ologist/microbial biogeochemist at the assistant professor level, starting September 2007. Individu-als with experience and a continuing interest in applications of genomic, molecular, or isotopic approaches of geomicrobiology and/or microbial biogeochemistry to earth and marine science problems are encouraged to apply. Priority will be given to applicants who complement existing strengths in the Department of Geological Sci-ences and provide interactions with other closely related departments at the University of Michigan.

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Applications should be submitted prior to October 30th, 2006, for full consideration, but applications will continue to be reviewed until the position is filled:

Chair, Search CommitteeGeomicrobiology/Microbial BiogeochemistryDepartment of Geological Sciences1100 N. University AvenueUniversity of MichiganAnn Arbor, MI 48109-1005The University of Michigan is a non-discrimi-

natory/affirmative action employer. Women and minorities are encouraged to apply. The University is supportive of the needs of dual career couples.

Instrument Support Specialist/ Analytical Labo-ratory Manager, Fisher College of Science and Mathematics. The Fischer College of Science and Mathematics at Towson University seeks a scien-tist with demonstrable technical skills as its Instru-ment Support Specialist/Analytical Laboratory Manager. This is a full-time, 12-month position with full University benefits.

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The Laboratory Manager will also be respon-sible for the oversight and development of new analytical methods and QA/QC protocols, and supervise and train facility users. Additional opportunities may be available to participate in UEBL research projects and contractual work.

Requirements: Bachelor’s degree and one year analytical instrumentation experience with at least one of the core UEBL instruments. Master’s preferred in a related scientific discipline as well as experience with ICP-MS and biogeochemical sample preparation. Well qualified individuals

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were mainly hardware-related. Early hard-ware platforms were based on infrared data transfer, causing some problems with the system’s reliability. Receivers seemed unable to simultaneously accept 200 infrared sig-nals from students straining to point their transmitters in various directions, so their signals would be received like so many mal-functioning television remotes. In addition, the students’ infrared transmitters were not durable enough. Many times, instructors needed to accept hand-written answers after class, and every time a student would get a new transmitter, their transmitter code num-ber had to be updated in the software. The clerical work became burdensome.

This year, the instructors have switched to a radio frequency transmitter system. These transmitters need not be pointed in a partic-ular direction and they are more durable. However, software difficulties persist, mainly regarding transmitter code numbers (which were collected this year through a Web-based interface registration) and classroom presentation settings. But these difficulties are to be expected in early versions of both hardware and software. The system now is running relatively smoothly, and by the end of this year the system likely will to be ready for ‘prime time’—more sustained use in other beginning Earth science classes at the University of Florida and other schools.

An unavoidable aggravation in using this system is of the same nature as is faced by all instructors teaching a class of hundreds. If only 1% of students each day have an excuse for why they forgot or lost their trans-mitter or were absent and should be awarded the points they missed, an instructor must deal with several of these petitions each day. Some of this inconvenience can be mini-mized with the proper setup of grading poli-cies. However, clerical time is decreased through the automation of the grading of quizzes and other class exercises. A student’s

complete day-by-day attendance and perfor-mance record is easily generated (useful when end-of-semester plaintive petitions are received). An added pleasure is easily being able to poll the class on any topic—from the upcoming football game to their choice of the next topic to cover—and to have the students immediately see the anonymous opinions of their peers.

Of course, some lecture time (and possi-bly some content) must be sacrificed in order to run this type of activity. But instruc-tors should be willing to teach students less material in exchange for teaching it better. While it is admittedly distasteful that teacher-student dialogue is reduced to an exchange of radio signals, the instructors participating in this study have qualitatively observed that the ‘forced’ interaction leads to increased questioning from the students.

Larger class sizes and distracted students are realities most instructors face, and while they may be uncomfortable with this new-fangled computer-reliant teaching technol-ogy, the students, lifelong members of the remote control generation, apparently are not. They understand its advantages and pit-falls and easily adapt to the new system. If they see that attending, paying close atten-tion, and participating in these classroom activities will directly affect their grade, they will do just that.

Last semester, a professor visited one of these classrooms during the very last week of classes to perform a teacher evaluation. He was amazed to see nearly every seat occupied and students at full attention. “I have never seen this before,” he exclaimed. “Whatever that remote control thing is doing, it must be working.”

Author information

Andrew R. Zimmerman and Matthew C. Smith, Department of Geological Sciences, University of Florida, Gainesville; E-mail: azimmer@ufl.edu

Zimmerman cont. from page 339

Quantifying the variation in motion of the Earth’s rotation pole on weekly scales The motion of the Earth’s rotation pole shows two large trends, one with a period of about 433 days corresponding to Chandler wobble (free Eulerian wobble), and another corresponding to annual oscillations forced by the seasonal displacement of air and water masses. Every 6.4 years, annual and Chandler wobbles combine to almost cancel each other out, severely reducing polar motion. Noting that between November 2005 and Febru-ary 2006 the Chandler and annual wobbles inter-fered destructively, Lambert et al. sought to charac-terize the small amount of wobble left, a value representing wobble on weekly scales. Using high-precision Earth orientation data for these days, the authors were able to observe directly the very small structures of this weekly wobble for the first time in the history of polar motion observation. They also calculated the polar motion predicted during this time interval from atmospheric and oceanic circulation models, and found that the centimeter-level polar motion displacements dur-ing the 2005-2006 winter season were almost fully explained by major pressure events on the conti-nents and on the ocean. (Geophysical Research Letters, doi:10.1029/2006GL026422, 2006)

Stratospheric O2/N2 ratios can help constrain carbon uptake budgets by the biosphere and ocean Fossil fuel burning reduces the oxygen/nitrogen (O2/N2) ratio in the troposphere as oxy-gen is captured to form carbon dioxide (CO2). This initial CO2 increase in the troposphere is tem-pered by oceanic CO2 uptake, which doesn’t affect atmospheric oxygen levels, and by land biotic uptake, which captures carbon and releases oxy-gen at a known rate that is smaller than the rate of CO2 burning. The net result of these processes is that over time, CO2 levels increase and O2/N2 ratios decrease in the troposphere. To study this further, Ishidoya et al. examined air samples col-lected from the stratosphere over Japan and Ant-arctica. They observed that the O2/N2 ratio decreased with height in this atmospheric layer, and through comparisons with diffusion models, suggested that this decrease is caused by a gravitational separa-tion of heavy O2 molecules from N2 molecules. The diffusion models, coupled with knowledge of tropospheric trends, allowed the authors to deduce the ages of their air samples, and thus the amount reduction in the tropospheric O2/N2 ratio. From this, the authors were able to calculate aver-age terrestrial biospheric and oceanic CO2 uptake for October 1993 through September 2001. (Geo-physical Research Letters, doi:10.1029/2006GL025886, 2006)

Mantle transition zone is not caused by high-pressure hydrous derivatives of olivine Phase transitions among olivine and its high-pressure derivatives, wadsleyite and ringwoodite, are thought to be responsible for the seismic velocity discontinuities in the transition zone of the man-tle, between 400 and 660 kilometers in depth. Recent studies of ringwoodite show that it can house vast quantities of water and that the incor-poration of water results in a substantial decrease

in rignwoodite’s elastic moduli. Noting that past studies suggested that this could be responsible for trends in the mantle’s seismic profile, Wang et al. investigated the elastic properties of hydrous ring-woodite at high-pressure room-temperature condi-tions. They found that at mantle pressures, the hydra-tion of ringwoodite can increase pressure derivatives of elastic moduli up to 7% for the bulk modulus and 30% for the shear modulus when compared with anhydrous ringwoodite. However, the velocity gradients as a function of pressure for hydrous ringwoodite are significantly less then the corre-sponding gradients in the Earth’s transition zone. Thus, the authors concluded that the transition zone seismic velocity gradients are not due to ‘wet’ ringwoodite, as previously speculated. (Geophysical Research Letters, doi:10.1029/2006GL026441, 2006)

Remote sensing of sea surface temperature is influenced by ocean slicks Infrared measure-ments of sea surface temperature (SST) typically survey a very thin surface layer of the ocean, approximately 10 micrometers thick. Past ocean studies revealed the presence of natural filmed surfaces, or ‘slicks’, which possess a surface-active agent that reduces fluidity. Marmorino and Smith sought to more rigorously understand the behav-ior of slicks. They collected airborne infrared imagery over the ocean and found that slicks are 0.1 to 0.4°C cooler than the surrounding water surface. Through comparing this with data on sea surface roughness, an indicator of wind condi-tions and ocean turbulence, the authors found that the thermal contrast of slicks was higher dur-ing calmer sea conditions. They noted that such studies can help determine errors in bulk SST retrievals, can act as a potential source of informa-tion about the ambient thermal boundary layer, and may help monitor plankton blooms, assess error in wind-retrieval algorithms, and refine stud-ies of air-sea gas exchange. (Geophysical Research Letters, doi:10.1029/2006GL026502, 2006)

Changes in the pace of the water cycle indi-cate that summer is bleeding into spring The water cycle is linked with natural nutrient cycles, and is influenced by agriculture and human soci-ety, which in turn influences ecosystem sustain-ability. Thus, a key question regarding climate change revolves around whether the hydrologic cycle is accelerating. To study this, Dirmeyer and Brubaker applied a water tracing algorithm using atmospheric analyses and observed precipitation for the period of 1979 and 2003. Using past atmo-spheric conditions including winds, temperature, and moisture content, the authors estimated over all land regions of the globe how much evapo-rated water could have fallen back as precipita-tion over the same area. Comparing this to total precipitation measured over the region gives the water recycling ratio. They found that seasonal trends of this ratio are changing over northern lati-tudes, consistent with an expansion into spring of the warmer-season’s regime of water vapor recy-cling. This trend is also consistent with observed vegetation-related changes often attributed to global climate change. (Geophysical Research Let-ters, doi:10.1029/2006GL026359, 2006)

A G U J O U R N A LH I G H L I G H T S

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