A comparative study of baseball bat performance

The results of a comparative study of five aluminum and one wood baseball bats are presented. The study includes an analysis of field data, high-speed laboratory testing, and modal analysis. It is found that field performance is strongly correlated with the ball–bat coefficient of restitution (BBCOR) and only weakly correlated with other parameters of the bat, suggesting that the BBCOR is the primary feature of a bat that determines its field performance. It is further found that the instantaneous rotation axis of the bat at the moment of impact is very close to the knob of the bat and that the rotational velocity varies inversely with the moment of inertia of the bat about the knob. A swing speed formula is derived from the field data and the limits of its validity are discussed. The field and laboratory measurements of the collision efficiency are generally in good agreement, as expected on theoretical grounds. Finally, the BBCOR is strongly correlated with the frequency of the lowest hoop mode of the hollow bats, as predicted by models of the trampoline effect.     

Has Bartel resolved the gamer’s dilemma?

In this paper we consider whether Christopher Bartel has resolved the gamer’s dilemma. The gamer’s dilemma highlights a discrepancy in our moral judgements about the permissibility of performing certain actions in computer games. Many gamers have the intuition that virtual murder is permissible in computer games, whereas virtual paedophilia is not. Yet finding a relevant moral distinction to ground such intuitions can be difficult. Bartel suggests a relevant moral distinction may turn on the notion that virtual paedophilia harms women in a way that virtual murder does not. We argue that this distinction is only in a position to provide a partial solution to the dilemma.     

Using Movies to Illustrate Ethical Dilemmas in Undergraduate Criminal Justice Classes

Ethics education in criminal justice programs has increased in popularity, but instructors sometimes struggle to teach ethics in such a way that students retain what they have learned and apply ethical principles in the criminal justice field upon graduation. The current research highlights that there are several benefits of presenting ethical dilemmas to students through popular movies such as Mississippi Burning and Road to Perdition. Compared to the control group (Section A) that was taught in a traditional lecture format, students who were required to identify ethical dilemmas in movies (Section B) were more likely to understand the complexities of such situations, to rate unethical behavior properly, and to see how ethical principles could be applied to their everyday lives.     

Designing Educational Video Games to Be Objects-to-Think-With

In this article we propose that educational game design should work to create games as objects-to-think-with—games that engage players in the exploration of and experimentation with personally interesting questions around domain-relevant representations. We argue that this design focuses on developing tools and interactions that the player can use for inquiry and productive thinking. As a step toward achieving this goal, we propose the constructible authentic representations design principle and illustrate this principle using a prototype game, Particles!, for exploring the particulate nature of matter. Observations of game play and interviews with 9 children ages 11–14 suggest that core game representations and mechanics provided players with a space for engaging in useful scientific practices and knowledge resources for reasoning about the important role molecular structure plays in material properties beyond the game. We explore how this design proposal extends and complements existing constructivist game design frameworks. Furthermore, we suggest that the framework of games as objects-to-think-with should push the educational game design community to consider the complexity and nuance of cognition and to embrace and champion the learner in game design.     

Predicting College Performance of American Indians: A Large‐Sample Examination of the SAT

Extensive research has examined the validity and fairness of standardized tests in academic admissions. However, due to their underrepresentation in higher education, American Indians have gained much less attention in this research. In the present study, we examined for American Indian students (1) group differences on SAT scores, (2) the predictive and incremental validity of SAT over high school grades, (3) the effect of socioeconomic status on SAT validity, (4) differential prediction in the use of SAT scores, and (5) potential omitted variables that could explain differential prediction for American Indian students. Results provided evidence of predictive and incremental validity of SAT scores, and the validity of SAT scores was largely independent of socioeconomic status. Overprediction was found when using SAT scores to predict college performance and it was reduced when including high school grades as an additional predictor. This study provides substantial evidence of the validity and fairness of SAT scores for American Indians.     

How Do Academic Disciplines Use PowerPoint?

How do academic disciplines use PowerPoint? This project analyzed PowerPoint files created by an academic publisher to supplement textbooks. An automated analysis of 30,263 files revealed clear differences by disciplines. Single-paradigm “hard” disciplines used less complex writing but had more words than multi-paradigm “soft” disciplines. The “hard” disciplines also used a greater number of small graphics and fewer large ones. Disciplines identified by students as being more effective users of PowerPoint used larger images and more complex sentences than disciplines identified as being less effective in this regard. This investigation suggests that PowerPoint best practices are not universal and that we need to account for disciplinary differences when creating presentation guidelines.