Scott K. Clark

High Precision Measurement of Selenium Isotopic Composition by Hydride Generation Multiple Collector Inductively Coupled Plasma Mass Spectrometry with a 74Se-77Se Double Spike

Abstract A method was developed for high precision measurement of selenium isotopes by hydride generator-multiple collector inductively couple plasma mass spectrometer (HG-MC-ICP-MS) using 74 Se- 77 Se double spike and modified thiol-cotton purification. Selenium was separated from the sample matrix using thiol-cotton, and HNO 3 + H 2 O 2 separates Se from organic matter in the thiol-cotton that could interfere with hydride generation. The 74 Se- 77 Se double spike corrects for isotope fractionation during purification and mass spectrometry analysis. The external reproducibility for standard NIST SRM3149/MH495 and natural samples were 0.1‰ (2σ) and 0.15‰–0.2‰ (2σ) over the course of several months, respectively. Based on the average yield (85%) of Se separation using thiol-cotton, the minimum quantity of Se for isotope analysis was approximately 20 ng. The results of an interlaboratory standard, MH495, δ 82/76 SRM3149 = (–3.44 ± 0.1)‰ (2σ), are in good agreement with previously published data δ 82/76 MH495 VS SRM3149 = (–3.04 ± 0.5)‰ that used a sample-standard bracketing technique. Selenium isotopes were measured in several sedimentary samples with a range from −13.53‰ to 9.03‰ relative to NIST SRM3149. These results suggest a potentially wide application of Se isotopes in environmental, geological, agricultural, and life sciences fields.

Alternative Conceptions of Plate Tectonics Held by Nonscience Undergraduates

Abstract The theory of plate tectonics is the conceptual model through which most dynamic processes on Earth are understood. A solid understanding of the basic tenets of this theory is crucial in developing a scientifically literate public and future geoscientists. The size of plates and scale of tectonic processes are inherently unobservable, necessitating the use of images and models in instruction. To explore plate tectonics conceptions held by undergraduates, we designed and administered a postinstruction survey instrument centered on a common schematic representation of plate tectonics. We report results from a sample of n =60 nongeoscience majors enrolled in five different introductory Earth-science courses taught at a major research university and a community college. Students held a number of alternative conceptions associated with terminology, plate motion, and plate-related subsurface melting. We also note that some aspects of figures commonly used to teach plate tectonics are problematic for students and may actually result in reinforcement of alternative conceptions. Further work at both the K–12 and college levels directed at innovative approaches to address student conceptions regarding plate tectonics, including designing images that support key scientific messages, is needed. This research can inform curriculum development for entry-level geoscience courses as well as the use of images to convey complex science.

A Shift in Scientific Literacy: Earthquakes Generate Tsunamis

Scientific literacy is a fundamentally important prerequisite for decision making in this global age, particularly when it comes to decisions that affect our health, environment, technological advancement, and community development. A scientifically literate populace should be proficient at reading and interpreting science news articles [National Research Council, 1996]. For this to occur, terminology in news reports needs to be scientifically accurate. As scientists, we often resign ourselves to the reality that scientific accuracy in mainstream news reports sometimes falls short of what we would hope. However, in at least one case, the use of appropriate terminology in news reports has clearly improved. Prior to the devastating 26 December 2004 Indian Ocean earthquake and tsunami, nearly one in four newspaper and wire service articles that discussed earthquakes and tsunamis exclusively used the term “tidal wave” in lieu of “tsunami.” That ratio has decreased to less than one in 35 since the 26 December 2004 event. The apparent permanence of this lexical shift is demonstrated by the nearly unanimous use of the term tsunami in media reports of the 12 January 2010 Haitian and 27 February 2010 Chilean tsunamis, and provides an example of the impact natural disasters can have on scientific discourse in the news media.

Sustainability attitudes and behavioral motivations of college students: Testing the extended parallel process model

Purpose A planet that can no longer sustain life is a frightening thought – and one that is often present in mass media messages. Therefore, this study aims to test the components of a classic fear appeal theory, the extended parallel process model (EPPM) and to determine how well its constructs predict sustainability behavioral intentions. This study also strove to uncover students’ motivations and attitudes that are not present in the EPPM. Design/methodology/approach An online survey of 779 college students was conducted. Findings Results reveal that both threat and efficacy are significant predictors of behavioral intention, consistent with the EPPM. However, an analysis of open-ended comments reveals that subjective normative influence and incentives also play a key role in students performing future sustainable behaviors. Practical implications These findings provide a framework to educators and message designers of sustainability groups on college campuses highlighting the importance of including multiple constructs in their messages to students. Threatening messages will not be enough to increase behavioral intentions. Fear inducing messages must be combined with messages to increase self- and response efficacy. Education is also not the only piece of the puzzle. Students state difficulty in performing some sustainable behaviors as a key barrier, indicating a need to incorporate infrastructure changes at campuses to facilitate greater ease among students to act sustainably. Originality value This study tests the EPPM’s utility in helping to find the most effective ways to influence college students’ future behavioral intentions toward acting sustainably.

Factors influencing non-expert term usage during a disaster: An analysis of the 2004 Indian Ocean tsunami

Understanding how the general public uses science terminology during disasters has implications for improving communication between disaster experts and the public and for informing efforts designed to cultivate science literacy. This study presents an analysis of quotes in U.S. newspaper and newswire articles from people who identified the 26 December 2004 Indian Ocean tsunami either as a tidal wave or as a tsunami immediately after the disaster. Quotes from 147 individuals were assigned codes based on their location, nationality, and connection to the event. Individuals coded as experts (n = 16) only uttered tsunami . English-speaking non–tsunami experts in impacted countries were significantly more likely to identify the tsunami as a tidal wave than were individuals in non-impacted countries. Of 31 quoted non–tsunami experts who were in an impacted country, 52% described the disaster as a tidal wave ; only 2% of distal non–tsunami experts (n = 100) uttered tidal wave . Of particular note, four of ten quoted tourists from the U.S. who experienced the tsunami uttered tidal wave , whereas none of 27 quoted residents in the U.S. did so. Our results suggest that even if people are aware of appropriate terminology, many individuals will utter more familiar, colloquial, and linguistically simpler words instead of more accurate terminology, especially when experiencing elevated levels of stress, such as during the aftermath of a disaster. The implication for disaster communication efforts is that while a term that was once considered jargon can become widely known and adopted, many people will resort to a more familiar term unless the scientific jargon resonates with their personal, conceptual image of the disaster.

Commentary: A Brief Note on Misconceptions Regarding the Candle- and-Tumbler Experiment

A recent Journal of Geoscience Education article by Kovacs (2008) nicely highlighted a number of inquirybased and active-learning techniques that can be used in entry-level meteorology courses. These techniques, including think-pair-share, group activities, role-playing, and jigsaw puzzle activities, were discussed in the context of helping education majors obtain both the scientific content and methods needed to better prepare them for teaching careers. Also mentioned in the article was a common in-class experiment wherein a burning candle sitting in a pool of water is entrapped within a glass jar (the “tumbler” in the title). In this experiment, bubbles may be observed as air escapes out of the jar immediately after it contacts the water. Subsequently, the flame fades suffocates, and the water level inside the jar rises to fill approximately 20% of the total volume of the jar. This candle-and-tumbler experiment can encourage scientific reasoning about complex systems by providing an excellent opportunity for students to make numerous observations, and to conceptualize, discuss, and test multiple hypotheses. Unfortunately, the coincidence that the volume of air replaced by water in the jar is close to the fraction of O2(g) in the atmosphere has led some to misinterpret this experiment as appropriate for measuring the relative amount of oxygen in the atmosphere (e.g., Businger, 1996; Caplan et al., 1994; Kovacs, 2008). At most, only 6% of atmospheric oxygen will be consumed by a fire (Belcher and McElwain, 2008), and when this experiment is conducted using an Erlenmeyer flask or similarly shaped jar, such as a salad dressing jar, the water can rise to fill more than 25% of the jar’s total volume. Other readily accessible classroom experiments, such as one that uses damp steel wool (Birk et al., 1981), are more useful for measuring O2(g) in the atmosphere. The misconception that this experiment measures the proportion of oxygen in the atmosphere has been addressed by a number of researchers (Birk and Lawson, 1999; Glanz, 1963; Peckham, 1993). Yet, the candle-andtumbler experiment continues to be published as an appropriate exercise for determining the fraction of oxygen in the atmosphere. The pervasiveness of this misconception suggests that the explanation for why the water level rises into the jar needs to be revisited. Using C25H52 (pentacosane) to represent the chemical composition of the candle, the chemical reaction that occurs when a candle burns can be expressed as: