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JGE 1999 - Volume 47


An Introductory Geophysical Exercise Demonstrating the Use of the Gravity Method in Mineral Exploration
Micheal Charles Dentith and Micheal Robert Wheatley, The University of Western Australia

Teaching geophysics to earth-science classes can present particular difficulties. This is because the majority of students are often numerically weak, but the presence of a few highly numerate individuals is not uncommon. Due to its conceptual simplicity, the gravity method is recommended as the starting point for an introductory course in geophysics. This is because the physics behind the method is conceptually straightforward and the rationale for the reduction and interpretation of the data can be easily understood based on simple equations. Also, widely applicable concepts can be introduced within a relatively simple context.

An exercise based on the use gravity measurements for exploration for a manganese deposit in the north of Western Australia is described. During this exercise, following reduction of the data, regional and residual anomalies must be separated and the latter interpreted in terms of the depth to its source and the excess mass causing the anomaly. To illustrate the different corrections in the reduction process and their relative magnitudes, a Macintosh-based programs calculates drift, elevation, and the latitude corrections for a profile of gravity observations and plots the profile after each correction has been applied. Survey parameters such as trend, elevations along the profile, and reduction density can be interactively adjusted and the effect on the Bouguer anomaly observed.

Keywords: Education - computer assisted, geophysics - applied, miscellaneous and mathematical geology.
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Promoting andevaluating participation in high-enrollment undergraduate courses
Barbara Murck, University of Toronto at Mississauga

A particular challenge for instructors of high-enrollment (200+ students) classes is to encourage students to attend class regularly and to participate actively in learning. An adaptable form of "Participation Day" exercise which has been used successfully in large classes is the "One-Minute Essay," in which students are given one minute to write down something they have learned in class that day. One-Minute Essays encourage attendance, active participation, and mental involvement in course material, and they enhance contact between instructor and students. Ideally, Participation Day exercises should represent a component of the course mark. They also must be manageable in terms of required class time for the activity; require a minimum amount of marking time; be generally adaptable to very large class sizes; involve writing, if possible; and encourage students to interact with one another.

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A Comprehensive Stream Study Designed for an Undergraduate Non-Majors Course in Earth Science
Frank Morris Dunnivant, Ronald Brzenk and Alexandra Moore, Hartwick college

Science courses for students not majoring in science present unique teaching challenges to educators. Often non-science majors need help seeing the relevance of the course material and making connections between science and their own lives. One promising way to motivate these students and increase their level of interest and understanding is to teach in an integrated lab/lecture format using inquiry-based methods. Such activities maintain a constant level of attention from the students by requiring them to collect their own data, analyze the data set, interpret their data, and prepare a class presentation of their findings. We are experimenting with a new set of science courses that are designed to be interdepartmentally staffed, to integrate aspects of mathematics, geology, chemistry, and biology in an environmental theme, and to use guided-inquiry methods in a lab/lecture format. The interdisciplinary faculty team provides students with a diverse set of backgrounds and skills, and the interaction between instructors allows the students to observe the connection among the different sciences. The laboratory described below is a typical exercise drawn from our curriculum. We have modified a classic exercise in stream hydrology by integrating each of the scientific disciplines listed above in order to illustrate the advantages of interdisciplinary, guided-inquiry teaching methods. We find that an interactive approach greatly improves the students' critical-thinking sills and stimulates scientific curiosity as compared to traditional lecture methods. While our new curriculum is facilitated by external funding and the commitment of our administration and science faculty, we believe that the exercise presented here is very flexible and can be undertaken by earth-science faculty in a variety of educational contexts.

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An exercise in Forecasting the Next Mauna Loa Eruption
Stephen Ross Mattox, Grand Valley State University

Mauna Loa, on the island of Hawaii, is one of the studied volcanoes on Earth. Based on Mauna Loa's long historic record and detailed geologic mapping, volcanologists have published forecasts for futrue activity at the volcano. The mean recurrence interval for eruptions at Mauna Loa is 1,459 days. The probability of the next eruption of Mauna Loa during or before the year 2009 exceeds 50%. The eruption should send lava flows away from the town of Hilo (assuming the active vent is in the northeast rift zone) and produce about 323x10^6 m^3 of lava. This inquiry-based exercise requires students to think like scientists while interpreting data about Mauna Loa's past activity. Students will forecast the next eruption of Mauna Loa, predict the location of the vent, and estimate the amount of lava that will be produced.

Keywords: Education - undergraduate; education - precollege; geology - teaching and curriculum; volcanoes and volcanism.

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Systems Modeling of Nonequilibirum Chemical Reactions Using STELLA
Jonathon Levy and Larry Mayer, Miami University

Understanding mathematical models of chemical reactions is central to the fields of geology, geochemisty, and contaminant hydrogeology. Unfortunately, many students struggle with understanding the relations between the mathematics and the physical reality. Even upper-level undergraduate students oftern midunderstand fundamental concepts such as chemical equilibrium. To address the question of how to provide students with strong conceptual and qualitative reinforcement of systems in general and how to better understand chemical reactions in particular, we developed an exercise using STELLA to model a sorption-reaction system. STELLA enables students to build dynamic systems graphically from a physically based conceptual model independent of the governing differential equations. Using their STELLA models, students can gain insights into the system, observe relationships among model parameters and results, and discover new insights into what chemical equilibrium means and implies. Students can also explore their STELLA models to discover connections to the mathematical representation, thereby gaining a deeper appreciation of the mathematics behind the model and ultimately strengthening their mathematical skills.

Keywords: Education - computer assisted; education - graduate; education - undergraduate; geochemistry; hydrogeology and hydrology; miscellaneous and mathematical geology.

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