Corpuscularian Research Articles

Fifth grade science students’ modelling performance when using a particle model of matter to explain different phenomena connected to phase transitions

Models and modelling are key features in science. A particle model of matter is a basic model to explain the properties of substances and phase transitions. This study aims to gain insight into the modelling skills of 5th grade students who had been explicitly taught about models and a particle model of matter. The students’ ability to transfer their understanding of the particle model of matter to new contexts was studied, to see if prior modelling knowledge was transferable. The results showed that the students had an increase in sophistication level in their models, understood what needed to be included in a drawn model, and were also able to transfer some knowledge to a new context. This highlights how working with models and modelling helps students understand which explanatory entities are important when creating models in scientific teaching.

Towards detecting super-GeV dark matter via annihilation to neutrinos

The next generation of neutrino telescopes will feature unprecedented sensitivities in the detection of neutrinos. Here we study the capabilities of a large-scale neutrino telescope, like the fully-operating KM3NeT experiment in the near future, for detecting dark matter annihilation signals from the Galactic Centre.We consider both ORCA and ARCA detectors, covering dark matter masses from a few GeV to 100 TeV. We obtain the sensitivities with a maximum-likelihood analysis method and present them as upper limits in the thermally averaged annihilation cross-section into Standard Model fermions. Our projections show that the sensitivity of such a neutrino telescope can reach the thermal relic line for mχ ≳ 1 TeV and for mχ ≃ few GeV, for the NFW dark matter density profile. This demonstrates that ORCA- and ARCA-like detectors will be able to perform competitive dark matter searches in a wide range of masses. The implications of these striking projections are investigated in a few selected dark matter particle models, where we show that neutrino telescopes are able to probe new parameter space.

Intersecting visual and verbal representations and levels of reasoning in the structure of matter learning progression

Learning progressions (LPs) are novel models for the development of assessments in science education, that often use a scale to categorize students’ levels of reasoning. Pictorial representations are important in chemistry teaching and learning, and also in LPs, but the differences between pictorial and verbal items in chemistry LPs is unclear. In this study, we examined an Ordered Multiple Choice (OMC) LP assessment of explanations of physical properties and processes in matter, that included equivalent verbal and pictorial items. A cohort of 235 grade 7 students that learned the particle model of matter, responded to these assessments and the data was analyzed in terms of their apparent levels of reasoning. We employed two analyses to examine the role of pictorial items in the level-based model of the LP: a polytomous RASCH analysis of the multiple-choice responses, and a verbal analysis of the students’ explanations of their choices. We found that our data does not fit a fine-grained, four-level model, but that it does fit a coarse-grained three-level model. In addition, when fitting the data to the three-level model, the pictorial items placed more students in the midlevel than their verbal counterparts. The verbal analysis showed that explanations of selections of pictures that represent a partial, midlevel understanding, were significantly less aligned with the details in the picture, than explanations of the correct, upper-level selections. Finally, the proportions of student explanations of both upper-level choices and midlevel choices that were aligned with the information in the pictures were correlated with the overall difficulty of the items. This suggests that complex pictorial representations of processes are less likely to reveal coherent reasoning.

Resolving puzzling phenomena by the simple particle model: examining thematic patterns of multimodal learning and teaching

ABSTRACT This paper examines the roles of multimodality and thematic patterns in the teaching of the particle model of matter. Although the particle model is a fundamental topic in science education, there is no consensus on (1) whether or not the model should be introduced in early grades and (2) how to introduce the model to students for the very first time. Drawing from teacher development projects in Sweden (Grade 3) and in Hong Kong (Grade 7), we suggest that the learning and teaching of the particle model can be facilitated by utilising a variety of modes. With multimodal scaffolding, Grade 3 students were able to demonstrate aspects of the particle model related to the expansion of gases in a warmer environment. The paper illustrates teaching episodes from the two projects in terms of (i) aspects of the particle model that were constructed using different semiotic modes, (ii) shifts in the salience of different modes in the teaching and learning process, and (iii) a thematic pattern that the classroom interactions adopted to explain puzzling phenomena. For a theoretical advancement, we suggest that thematic analysis should be extended to multimodal interactions.

Effect of polarisation and choice of event generator on spectra from dark matter annihilations

If indirect detection searches are to be used to discriminate between dark matter particle models, it is crucial to understand the expected energy spectra of secondary particles such as neutrinos, charged antiparticles and gamma rays emerging from dark matter annihilations in the local Universe. In this work we study the effect that both the choice of event generator and the polarisation of the final state particles can have on these predictions. For a variety of annihilation channels and dark matter masses, we compare yields obtained with Pythia8 and Herwig7 of all of the aforementioned secondary particle species. We investigate how polarised final states can change these results and do an extensive study of how the polarisation can impact the expected flux of neutrinos from dark matter annihilations in the centre of the Sun. We find that differences between the event generators are larger for yields of hadronic end products such as antiprotons, than for leptonic end products. Concerning polarisation, we conversely find the largest differences in the leptonic spectra. The large differences in the leptonic spectra point to the importance of including polarisation effects in searches for neutrinos from dark matter annihilations in the Sun. However, we find that these differences are ultimately somewhat washed out by propagation effects of the neutrinos in the Sun.

Dark matter constraints from dwarf galaxies: a data-driven analysis

Dwarf galaxies represent a powerful probe of annihilating dark matter particle models, with gamma-ray data setting some of the best bounds available. A major issue in improving over existing constraints consists in the limited knowledge of the astrophysical background (mostly diffuse photons, but also unresolved sources). Perhaps more worrisome, several approaches in the literature suffer of the difficulty of assessing the systematic error due to background mis-modelling. Here we propose a data-driven method to estimate the background at the dwarf position and its uncertainty, relying on an appropriate use of the whole-sky data, via an optimisation procedure of the interpolation weights. While this article is mostly methodologically oriented, we also report the bounds based on latest Fermi-LAT data and updated information for J-factors for both isolated and stacked dwarfs. Our results are very competitive with the Fermi-LAT ones, while being derived with a more general and flexible method. We discuss the impact of profiling over the J-factor as well as over the background probability distribution function, with the latter resulting for instance crucial in drawing conclusions of compatibility with DM interpretations of the so-called Galactic Centre Excess.

Second graders’ emerging particle models of matter in the context of learning through model‐based inquiry

In this paper, we present a study of second graders’ learning about the nature of matter in the context of content-rich, model-based inquiry instruction. The goal of instruction was to help students learn to use simple particle models to explain states of matter and phase changes. We examined changes in students’ ideas about matter, the coherence of their emerging particle models, and how classroom science discourse influenced students’ learning. The study was conducted in two second grade classrooms in a rural Midwestern public school. We worked with the two teachers to help them design modeling activities for students to complement lessons from the Full Option Science System (FOSS™) science curriculum the teachers had previously used. Our data sources for student learning included individual interviews with students before and after they completed the set of Modeling in the Primary Grades (MPG) lessons, artifacts created by students during learning such as posters and science notebook entries, and videotapes of MPG lessons. Our findings suggest that second grade students who engaged in MPG model-based inquiry lessons learned to use simple particle models to describe and explain a variety of material phenomena. For example, they could use particle models to account for differences in the appearance and behavior of solids, liquids, and gases and to explain what happens to matter during phase transitions. We also found variations in how MPG teachers structured classroom discourse, and our results suggest that such variations are associated with differences in the coherence of student models. © 2017 Wiley Periodicals, Inc. J Res Sci Teach 9999:988–1023, 2017

A review of indirect searches for particle dark matter

The indirect detection of dark matter annihilation and decay using observations of photons, charged cosmic rays and neutrinos offers a promising means of identifying the particle nature of this elusive component of the universe. The last decade has seen substantial advances in observational data-sets, complemented by new insights from numerical simulations, which together have enabled for the first time strong constraints on dark matter particle models, and have revealed several intriguing hints of possible signals. This review provides an introduction to indirect detection methods and an overview of recent results in the field.

Key-Aspects of Scientific Modeling Exemplified by School Science Models: Some Units for Teaching Contextualized Scientific Methodology

Models and modeling are core elements of scientific methods and consequently also are of key importance for the conception and teaching of scientific methodology. The epistemology of models and its transfer and adaption to nature of science education are not, however, simple themes. We present some conceptual units in which school science models are used for exemplifying aspects and issues that we consider crucial for an understanding of models and modelling, such as: the perspectival and conceptual character of models, their mediating, interpretive and predictive function, and the nature and potentialities of theoretical–mathematical models. The models used to exemplify these aspects are some particle models of matter, Newton’s two-body planetary model, and models of mechanical oscillations. The units are designed as a NOS education series for teachers and upper high school students, but they could also be used independently. The underlying concept for designing the units is based on teaching scientific methodology explicitly and contextualized in curricular science content.

Berkeley’s Immaterialistic Corpuscularianism: The Problem of Yet to Have Been Perceived Objects

Berkeley’s Immaterialistic Corpuscularianism: The Problem of Yet to Have Been Perceived Objects

Dark matter relic density in Gauss-Bonnet braneworld cosmology

The relic density of symmetric and asymmetric dark matter in a Gauss-Bonnet (GB) modified Randall-Sundrum (RS) type II braneworld cosmology is investigated. The existing study of symmetric dark matter in a GB braneworld (Okada and Okada, 2009) found that the expansion rate was reduced compared to that in standard General Relativity (GR), thereby delaying particle freeze-out and resulting in relic abundances which are suppressed by up to \U0001d4aa(10−2). This is in direct contrast to the behaviour observed in RS braneworlds where the expansion rate is enhanced and the final relic abundance boosted. However, this finding that relic abundances are suppressed in a GB braneworld is based upon a highly contrived situation in which the GB era evolves directly into a standard GR era, rather than passing through a RS era as is the general situation. This collapse of the RS era requires equating the mass scale mα of the GB modification and the mass scale mσ of the brane tension. However, if the GB contribution is to be considered as the lowest order correction from string theory to the RS action, we would expect mα > mσ. We investigate the effect upon the relic abundance of choosing more realistic values for the ratio ℛm ≡ mα/mσ and find that the relic abundance can be either enhanced or suppressed by more than two orders of magnitude. However, suppression only occurs for a small range of parameter choices and, overwhelmingly, the predominant situation is that of enhancement as we recover the usual Randall-Sundrum type behaviour in the limit ℛm ≫ 1. We use the latest observational bound ΩDMh2 = 0.1187 ± 0.0017 to constrain the various model parameters and briefly discuss the implications for direct/indirect dark matter detection experiments as well as dark matter particle models.

Framing Prospective Elementary Teachers’ Conceptions of Dissolving as a Ladder of Explanations

The paper details an exploratory qualitative study that investigated 61 prospective teachers’ conceptual understanding of dissolving salt and sugar in water respectively. The study was set within a 15-week elementary science methods course that included a 5E learning cycle lesson on dissolving, the instructional context. Oversby’s (Prim Sci Rev 63:6–19, 2002, Aspects of teaching secondary science, Routledge Falmer, London, 2002) ladder of explanations for the context of dissolving, current scientific explanations for dissolving and perspectives on conceptions and misconceptions provided the unified framework for the study. Concept maps, interview transcripts, written artifacts, and drawings and narratives were used as data to investigate these prospective teachers’ conceptual understanding of dissolving throughout the 15-weeks of the methods course. Analysis revealed that participants’ explanations of dissolving were predominantly descriptive explanations (39 %) and interpretative explanations (38 %), with lower percentage occurrences of intentional (14 %) and cause and effect (9 %) level explanations. Most of these explanations were also constructed by a set of loosely connected and reinforcing everyday concepts abstracted from common everyday experiences making them misconceptions. Implications include: (1) the need for science teacher educators to use multiple platforms to derive their prospective elementary teachers’ conceptual understandings of science content; and (2) to identify and help them identify their own scientific conceptions and misconceptions and how they influence the construction of scientific/nonscientific explanations. Science teacher educators also need to emphasize the role of meaningful frameworks associated with the concept that is being introduced during the Engage phase of the 5E learning cycle. This is important because, relevant prior knowledge is associated with the knowledge of the particle theory of matter and both are part of larger knowledge system comprised of interrelated scientific concepts.

Linguistic Resources Used in Grade 8 Students’ Submicro Level Explanations—Science Items from TIMSS 2007

Explanations involving submicro levels of representation are central to science education, but known to be difficult for students in secondary school. This study examines students' written explanations of physical and chemical phenomena regarding matter and changes in matter, in a large-scale test. This is done in order to understand linguistic challenges in constructing submicro level explanations involving the particle model of matter. Drawing from systemic functional linguistics, the lexicogrammatics used in explanations for realising experiential meaning in student explanations were analysed. We used answers to two partly constructed response items from the Swedish part of Trends in International Mathematics and Science Studies 2007, grade 8, to sort out explanations referring to the particle model of matter. These answers (86 from 954) were analysed regarding choices of vocabulary and grammar to distinguish between macro and submicro level of representation. The results show that students use a wide variety of lexicogrammatical resources to realise what happens on both macro and submicro level of representation, with greater diversity of verbs on the submicro level of explanation. The results suggest an uncertainty about the distinction between macro and submicro level of explanation.

VERITAS deep observations of the dwarf spheroidal galaxy Segue 1

The VERITAS array of Cherenkov telescopes has carried out a deep observational program on the nearby dwarf spheroidal galaxy Segue 1. We report on the results of nearly 48 hours of good quality selected data, taken between January 2010 and May 2011. No significant $\gamma$-ray emission is detected at the nominal position of Segue 1, and upper limits on the integrated flux are derived. According to recent studies, Segue 1 is the most dark matter-dominated dwarf spheroidal galaxy currently known. We derive stringent bounds on various annihilating and decaying dark matter particle models. The upper limits on the velocity-weighted annihilation cross-section are $\mathrm{<\sigma v >^{95% CL} \lesssim 10^{-23} cm^{3} s^{-1}}$, improving our limits from previous observations of dwarf spheroidal galaxies by at least a factor of two for dark matter particle masses $\mathrm{m_{\chi}\gtrsim 300 GeV}$. The lower limits on the decay lifetime are at the level of $\mathrm{\tau^{95% CL} \gtrsim 10^{24} s}$. Finally, we address the interpretation of the cosmic ray lepton anomalies measured by ATIC and PAMELA in terms of dark matter annihilation, and show that the VERITAS observations of Segue 1 disfavor such a scenario.

Conceptual change texts in chemistry teaching: A study on the particle model of matter

Conceptual change texts in chemistry teaching: A study on the particle model of matter

CONCEPTUAL CHANGE TEXTS IN CHEMISTRY TEACHING: A STUDY ON THE PARTICLE MODEL OF MATTER

This study explores the effect of a conceptual change text on students’ awareness of common misconceptions on the particle model of matter. The conceptual change text was designed based on principles of text comprehensibility, of conceptual change instruction and of instructional approaches how to introduce the particle model. It was evaluated in an empirical study with 214 students. Students’ learning was measured with a pre–post-test design. Item response theory was used for analysing students’ answers. We found that reading the criteria-based text fostered students’ awareness of common misconceptions about the particle model and yielded overall improved results as compared to reading a traditional text.

Phantom dark energy with varying-mass dark matter particles: Acceleration and cosmic coincidence problem

We investigate several varying-mass dark matter particle models in the framework of phantom cosmology. We examine whether there exist late-time cosmological solutions, corresponding to an accelerating universe and possessing dark energy and dark matter densities of the same order. Imposing exponential or power-law potentials and exponential or power-law mass dependence, we conclude that the coincidence problem cannot be solved or even alleviated. Thus, if dark energy is attributed to the phantom paradigm, varying-mass dark matter models cannot fulfill the basic requirement that led to their construction.

To what extent do different multiple intelligences affect sixth grade students’ achievement level on the particle model of matter?

In this study, multiple intelligences (MI) of sixth grade students were investigated to determine the extent to which they affect the students’ achievement on the topic of the particle model of matter. The study was conducted with four randomly selected elementary schools with a total 132 sixth grade students in the Spring 2008 semester. Pearson correlations and ANOVA tests results revealed that there were positive low correlations between achievement and mathematical-logical, visual-spatial, and interpersonal intelligences. Also, it was found out that bodily-kinesthetic learners’ achievement level were lower than mathematical-logical, visual-spatial, and musical learners. Similarly, naturalistic learners’ scores were lower than the mathematical-logical and visual-spatial learners.

The breaking of the Equivalence Principle in theories with varying α

AbstractThe Standard Model and General Relativity provide a good description of phenomena at low energy. These theories, which agree very well with the experiment, contain a set of parameters called “fundamental constants”, that are assumed invariant under changes in location and reference system. However, their possible variation has been studied since Dirac made the large numbers hypothesis (LNH). Moreover, unified field theory and extra dimensions theories such as Kaluza-Klein or Superstring theories, state not only the variation of these constants, but also the simultaneity of the variations.The Eötvös effect is one of the most sensitive indicators of changes in fundamental constants. Bekenstein (2002) showed that in his theory, using a classical static particle model of matter, there is no Eötvös effect and therefore met the Universality of Free Fall and the Principle of Equivalence.We present different results than those obtained by Bekenstein, Kraiselburd, Vucetich (2009). Modifying his theory, taking more realistic models of matter and using the model THεμ techniques (Ligtman-Lee (1975) and Haugan (1979), not used before to analyze this model), very small but measurable effects have been found.

Secondary Students’ Thinking about Familiar Phenomena: Learners’ explanations from a curriculum context where ‘particles’ is a key idea for organising teaching and learning

Particle models of matter are widely recognised as being of fundamental importance in many branches of modern science, and particle ideas are commonly introduced and developed in the secondary school curriculum. However, research undertaken in a range of national contexts has identified significant learning difficulties in this topic, and suggests that notions of particles that match scientific models are generally only attained over periods of some years. The implementation of a National Curriculum in Science in England was followed by increasingly prescriptive guidance to teachers. This culminated in a framework for teaching lower secondary science, which identified ‘particles’ as one of five key ideas for organising teaching and learning of science to all 11–14‐year‐olds. In this curriculum context, a basic particle model is introduced at the start of secondary education, and consolidated by being revisited in various contexts over three years. However, National Tests suggest that only a minority of pupils attain levels of understanding matching target knowledge. The present paper reports an interview study that explored how a sample of English secondary students explained phenomena commonly met in school science. It was found that students generally used the notion of particles, although most of their particle‐based explanations reflected alternative conceptions that have been reported in previous research. It is concluded that a curriculum strategy of early introduction and regular application during the early secondary years is not of itself sufficient to support the desired progression in thinking with particle models, and more sophisticated research‐informed pedagogy is needed.