TEACHERS’ MISCONCEPTIONS ABOUT THE EFFECTS OF ADDITION OF MORE REACTANTS OR PRODUCTS ON CHEMICAL EQUILIBRIUM     

Derek Cheung  Hong-jia Ma  Jie Yang 《International Journal of Science and Mathematics Education》2009,7(6):1111-1133

The importance of research on misconceptions about chemical equilibrium is well recognized by educators, but in the past, researchers’ interest has centered on student misconceptions and has neglected teacher misconceptions. Focusing on the effects of adding more reactants or products on chemical equilibrium, this article discusses the various misconceptions held by high school teachers. A misconception test was administered to two samples of chemistry teachers in Nanjing, China. Of the 109 teachers who participated in the test, only one understood that adding more CS₂ gas to the equilibrium system CS₂(g) + 4H₂(g) ⇌ CH₄(g) + 2H₂S(g) at constant pressure and temperature can shift the equilibrium to the reactant or product side, depending upon the amount of CS₂ in the initial equilibrium system. Most of the teachers relied on Le Chatelier’s principle and thus made erroneous predictions. The misconception test also revealed that those teachers who managed to compute equilibrium constants had a limited conceptual understanding of chemical equilibrium. Implications of these findings for teacher education and chemistry curriculum development are discussed.  相似文献   

Qualitative Differences Between Learning Environments Using Videos in Small Groups and Whole Class Discussions: A Preliminary Study in Physics     

Ashleigh Mayo  Manjula D. Sharma  Derek A. Muller 《Research in Science Education》2009,39(4):477-493

Interactivity, group learning and student engagement are accepted as key features of social constructivist learning theories. The challenge is to understand the interplay between such features in different learning environments. This study focused on the qualitative differences between two interventions—small-groups and whole-class discussions. In both interventions, three short video slices on the abstract topic ‘the physics of superconductivity’ were interspersed with the different discussion styles. The video slices are based on the Bruner stages. Twenty-nine first year university physics students completed a pre-test, underwent the intervention and completed a post-test. The remainder of the data were collected from student drawings, video recordings, observer notes and facilitator feedback. Results indicate that the use of the video slices in both interventions were successful in changing students’ understandings of superconductivity. However, the small groups treatment tended to facilitate questioning, meaning-making and subsequent changes of ideas more so than the whole class discussions. Implications for research and practice are discussed.  相似文献   

History effects on induced and operant variability     

da Silva Souza A  Abreu-Rodrigues J  Baumann AA 《Learning & behavior》2010,38(4):426-437

Two experiments evaluated history effects on induced and operant variability. College students typed three-digit sequences on a computer keyboard. Sequence variability was induced (by no reinforcement or variation- independent reinforcement) or reinforced (by variation- or repetition-dependent reinforcement). Conditions with induced and operant variability were presented according to a reverse between-groups design. In Experiment 1, we examined transitions from the variation or repetition contingencies to no reinforcement, and vice versa. In Experiment 2, the variation or repetition contingencies were followed or preceded by variation-independent reinforcement. The results showed that (1) a history of no reinforcement impaired operant variability learning; (2) induced variability levels were higher and lower after a history of reinforcement for variation and repetition, respectively; (3) repetition was more easily disrupted by no reinforcement and independent reinforcement than was variation; and (4) response variability and stability were a function of past and current reinforcement conditions. These results indicate that reinforcement history influences both induced and operant variability levels.  相似文献   

Futsal task constraints promote transfer of passing skill to soccer task constraints     

Luca Oppici  Derek Panchuk  Fabio Rubens Serpiello  Damian Farrow 《European Journal of Sport Science》2018,18(7):947-954

This study investigated how learning a passing skill with futsal or soccer task constraints influenced transfer to a new task. Futsal (n?=?24, 13.6?±?1.2 years old, 7.0?±?1.6 years of experience) and soccer (n?=?24, 13.6?±?1.2 years old, 6.8?±?1.2 years of experience) players performed two 5v5?+?goalkeeper modified games – a futsal-like task (small playing area with the futsal ball) and soccer-like task (large playing area with the soccer ball). Participants’ passing accuracy and their orientation of attention were assessed during the two tasks. The futsal group improved their passing accuracy (ES?=?0.75?±?0.61) from the futsal-like to the soccer-like task, and they were more accurate than soccer players (ES?=?2.98?±?2.96). Conversely, the soccer group’s passing accuracy remained stable across the two tasks (ES?=?0.10?±?0.52) and it was similar to the futsal group in the futsal-like task (ES?=?0.58?±?1.93). This indicates a higher magnitude of transfer (and adaptability) from performing passes in a small playing area with short time to act – futsal task constraints – to a larger playing area with longer time – soccer task constraints – than vice-versa. Furthermore, the futsal group showed a higher adaptation of attention orientation to the affordances that emerged with the soccer task constraints, which is suggested to be one of the main mechanisms promoting skill transfer. These results encourage soccer practitioners to introduce futsal task constraints to fast-track players’ ability to functionally adapt perception–action coupling.  相似文献   

The effects of resistance training volume on osteosarcopenic obesity in older women     

Paolo M. Cunha  Alex S. Ribeiro  Crisieli M. Tomeleri  Brad J. Schoenfeld  Analiza M. Silva  Mariana F. Souza 《Journal of sports sciences》2018,36(14):1564-1571

The aim of this study was to analyze the effects of resistance training (RT) performed with 1 or 3 sets per exercise on osteosarcopenic obesity (OSO) syndrome parameters in older women. Sixty-two older women (68.0 ± 4.3 years, 26.8 ± 4.4 kg/m²) participated in a 12-week RT program. Participants were randomly assigned into one of the three groups: two training groups that performed either 1 set (G1S, n = 21) or 3 sets (G3S, n = 20) 3 times weekly, or a control group (CG, n = 21). Body composition was assessed by dual X-ray absorptiometry, strength was evaluated by 1 repetition maximum testing. The G3S presented significantly higher strength changes than G1S. The changes for percentage of body fat were higher for G3S compared to G1S. There was no difference in skeletal muscle mass between G3S and G1S, however both training groups displayed greater increases in this outcome compared to CG. There was no effect for bone mineral density. The overall analysis indicated higher (P < 0.05) positive changes for G3S than G1S (composed Z-score: G3S = 0.62 ± 0.40; G1S = 0.11 ± 0.48). The results suggest that a 12-week RT period is effective to improve the risk factors of OSO, and that 3 sets induce higher improvements than a single set.  相似文献   

Protective effects of photobiomodulation against resistance exercise-induced muscle damage and inflammation in rats     

Helenita Antonia de Oliveira  Ednei Luiz Antonio  Flávio André Silva  Paulo de Tarso Camillo de Carvalho  Regiane Feliciano  Amanda Yoshizaki 《Journal of sports sciences》2018,36(20):2349-2357

We investigated whether low-level laser therapy (LLLT) prior to or post resistance exercise could attenuate muscle damage and inflammation. Female Wistar rats were assigned to non-LLLT or LLLT groups. An 830-nm DMC Laser Photon III was used to irradiate their hind legs with 2J, 4J, and 8J doses. Irradiations were performed prior to or post (4J) resistance exercise bouts. Resistance exercise consisted of four maximum load climbs. The load work during a resistance exercise bout was similar between Control (non-LLLT, 225 ± 10 g), 2J (215 ± 8 g), 4J (210 ± 9 g), and 8J (226 ± 9 g) groups. Prior LLLT did not induce climbing performance improvement, but exposure to 4J irradiation resulted in lower blood lactate levels post-exercise. The 4J dose decreased creatine kinase and lactic dehydrogenase levels post-exercise regardless of the time of application. Moreover, 4-J irradiation exposure significantly attenuated tumor necrosis factor alpha, interleukin-6, interleukin-1β, cytokine-induced neutrophil chemoattractant-1, and monocyte chemoattractant protein-1. There was minor macrophage muscle infiltration in 4J-exposed rats. These data indicate that LLLT prior to or post resistance exercise can reduce muscle damage and inflammation, resulting in muscle recovery improvement. We attempted to determine an ideal LLLT dose for suitable results, wherein 4J irradiation exposure showed a significant protective role.  相似文献   

“不是没有X”和“not without X”语义分析     

CHI Derek Asaba 《文学教育(上)》2018,(4)

双重否定是语言研究的一个重要范畴。双重否定是一种特殊的语法手段,是人们在否定的基础上通过二次否定的形式表达肯定的意思。在形式上,双重否定具有两个否定成分,但是在意义上却是肯定意义。不同语言表达双重否定的方式不一样。"不是没有X"和"not without X"是汉语和英语中的双重否定结构。这两个结构属于显性双重否定表达。本文通过对比以上两个结构的语义特点,分析这两者之间的共性及差异。  相似文献   

Do the Demographic Differences Manifest in Motivation to Learn Science and Impact on Science Performance? Evidence from Sri Lanka     

Anthoni Durage Asoka De Silva  Ali Khatibi  S. M. Ferdous Azam 《International Journal of Science and Mathematics Education》2018,16(1):47-67

The present study examined whether gender, ethnicity, instructional medium and school category differences manifest in science performance and motivation to learn science among secondary school students in Sri Lanka. The mean of five successive term test scores was used as the measure of science performance. Level of motivation in terms of six dimensions was measured by using the Science Motivation Questionnaire. A sample of 1316 grade 11 students representing Sinhala, Tamil, and Muslim ethnic groups from the three categories of public schools, which provide instructions in the vernacular languages of Sinhala or Tamil, participated in the study. Girls showed significantly higher performance in science compared to boys, and there was a significant gender difference in the levels of motivational dimensions in favor of girls. Although Tamil medium students possessed a higher level of motivation to learn science, Sinhala medium students outperformed their Tamil medium counterparts in science performance. Significant differences in science performance between Sinhala, Tamil, and Muslim students were also observed. However, motivation towards learning science between Tamils and Muslims was not significantly different. Highly significant differences in both motivation to learn science and performance in science were found between three categories of schools. The present study provides information to education officials who have to achieve equity across gender, ethnicity, medium of instruction, and school category, teachers who deliver the subject and school principals who design academic support programs.  相似文献   

Fluid ingestion and exercise hyperthermia: Implications for performance,thermoregulation, metabolism and the development of fatigue     

Derek Kay  Frank E. Marino 《Journal of sports sciences》2013,31(2):71-82

The development of fatigue during exercise and the subsequent onset of exhaustion occur earlier in the heat than in cooler environments. The underlying mechanisms responsible for the premature development of fatigue in the heat have yet to be clearly identified. However, the proposed mechanisms include metabolic, cardiovascular and central nervous system perturbations, together with an elevated core temperature. Fluid ingestion is one of three strategies that have been shown to be successful in enhancing the performance of endurance exercise in the heat, with the other interventions being precooling and acclimatization. However, like the development of fatigue in the heat, the mechanisms by which fluid ingestion allows for improved exercise performance remain unclear. We propose that fluid ingestion enhances exercise performance in the heat by increasing the heat storage capacity of the body. We suggest that the thermoregulatory, metabolic and cardiovascular alterations that occur as a result of this increased heat storage capacity contribute to performance enhancement when fluid is ingested during exercise heat stress.  相似文献   

Effect of verbal instructions and image size on visual search strategies in basketball free throw shooting     

Saleh A. Al-Abood  Simon J. Bennett  Francisco Moreno Hernandez  Derek Ashford  Keith Davids 《Journal of sports sciences》2013,31(3):271-278

We assessed the effects on basketball free throw performance of two types of verbal directions with an external attentional focus. Novices ( n = 16) were pre-tested on free throw performance and assigned to two groups of similar ability ( n = 8 in each). Both groups received verbal instructions with an external focus on either movement dynamics (movement form) or movement effects (e.g. ball trajectory relative to basket). The participants also observed a skilled model performing the task on either a small or large screen monitor, to ascertain the effects of visual presentation mode on task performance. After observation of six videotaped trials, all participants were given a post-test. Visual search patterns were monitored during observation and cross-referenced with performance on the pre- and post-test. Group effects were noted for verbal instructions and image size on visual search strategies and free throw performance. The 'movement effects' group saw a significant improvement in outcome scores between the pre-test and post-test. These results supported evidence that this group spent more viewing time on information outside the body than the 'movement dynamics' group. Image size affected both groups equally with more fixations of shorter duration when viewing the small screen. The results support the benefits of instructions when observing a model with an external focus on movement effects, not dynamics.  相似文献