Task-related models for teaching and assessing iteration learning in high school

A number of studies report about students’ difficulties with basic flow-control constructs, and specifically with iteration. Although such issues are less explored in the context of pre-tertiary education, this seems to be especially the case for high-school programming learning, where the difficulties concern both the “mechanical” features of the notional machine as well as the logical aspects connected with the constructs, ranging from the implications of loop conditions to a more abstract grasp of the underlying algorithms. For these reasons, the aim of this work is to: i) identifying methodological tools to enhance a comprehensive understanding of the iteration constructs, ii) suggest strategies to teach iterations. We interviewed 20 experienced upper secondary teachers of introductory programming in different kinds of schools. The interviews were mainly aimed at ascertaining teachers’ beliefs about major sources of issues for basic programming concepts and their approach to the teaching and learning of iteration constructs. Once teachers’ perception of students’ difficulties have been identified, we have submitted, to a sample of 164 students, a survey which included both questions on their subjective perception of difficulty and simple tasks probing their understanding of iteration. Data collected from teachers and students confirm that iteration is a central programming concept and indicate that the treatment of conditions and nested constructs are major sources of students’ difficulties with iteration. The interviews allowed us to identify a list of problems that are typically presented by teachers to explain the iterations. Hence, a catalogue of significant program examples has been built to support students’ learning, tasks with characteristics different from those typically presented in class. Based on the outcome of previous steps, a survey to collect related information and good practices from a larger sample of teachers has been designed. Data collected have been analysed distinguishing an orientation towards more conceptual objectives, and one towards more practical objectives. Furthermore, regarding evaluation, a orientation focused on process-based assessment and another on product-based assessment. Finally, based on the outcome of previous students’ survey and drawing from the proposed examples catalogue, we have designed and submitted a new students’ survey, composed of a set of small tasks, or tasklets, to investigate in more depth on high-school students’ understanding of iteration in terms of code reading abilities. The chosen tasklets covered the different topics: technical program feature, correlation between tracing effort and abstraction, the role of flow-charts, students’ perception of self-confidence concerning high-level thinking skills.A number of studies report about students’ difficulties with basic flow-control constructs, and specifically with iteration. Although such issues are less explored in the context of pre-tertiary education, this seems to be especially the case for high-school programming learning, where the difficulties concern both the “mechanical” features of the notional machine as well as the logical aspects connected with the constructs, ranging from the implications of loop conditions to a more abstract grasp of the underlying algorithms. For these reasons, the aim of this work is to: i) identifying methodological tools to enhance a comprehensive understanding of the iteration constructs, ii) suggest strategies to teach iterations. We interviewed 20 experienced upper secondary teachers of introductory programming in different kinds of schools. The interviews were mainly aimed at ascertaining teachers’ beliefs about major sources of issues for basic programming concepts and their approach to the teaching and learning of iteration constructs. Once teachers’ perception of students’ difficulties have been identified, we have submitted, to a sample of 164 students, a survey which included both questions on their subjective perception of difficulty and simple tasks probing their understanding of iteration. Data collected from teachers and students confirm that iteration is a central programming concept and indicate that the treatment of conditions and nested constructs are major sources of students’ difficulties with iteration. The interviews allowed us to identify a list of problems that are typically presented by teachers to explain the iterations. Hence, a catalogue of significant program examples has been built to support students’ learning, tasks with characteristics different from those typically presented in class. Based on the outcome of previous steps, a survey to collect related information and good practices from a larger sample of teachers has been designed. Data collected have been analysed distinguishing an orientation towards more conceptual objectives, and one towards more practical objectives. Furthermore, regarding evaluation, a orientation focused on process-based assessment and another on product-based assessment. Finally, based on the outcome of previous students’ survey and drawing from the proposed examples catalogue, we have designed and submitted a new students’ survey, composed of a set of small tasks, or tasklets, to investigate in more depth on high-school students’ understanding of iteration in terms of code reading abilities. The chosen tasklets covered the different topics: technical program feature, correlation between tracing effort and abstraction, the role of flow-charts, students’ perception of self-confidence concerning high-level thinking skills

An Exploration of High School Students' Self-Confidence while Analysing Iterative Code

A number of studies on novice programming report that loops and conditionals can be potential sources of errors and misconceptions. We then felt the need to engage in a more systematic and in-depth investigation about the teaching and learning of iteration in some representative high schools of our regional area. As a medium-term outcome of this endeavour we expect to get fine-grained insights about the nature of students' difficulties, on the one hand, as well as to identify possible pedagogical approaches to be adopted by teachers, on the other. As a step of this project, we designed and administered a survey composed of a set of small tasks, addressing students’ understanding of iteration in terms of code reading abilities. After summarising the motivations underlying the choice of the tasklets and the overall structure of the instrument, in this paper we will focus on a particular aspect which has not yet received extensive attention in the computer science education literature. Specifically, we will consider students' perception of self-confidence, in connection with their actual performance in each task, the specific program features, the cognitive demands (procedural vs. higher-level thinking skills), and the use of code vs. flow-charts. A noteworthy result of this analysis is that students’ perception of self-confidence is poorly correlated to actual performance in the task at hand. The main implications of our study are twofold, pertaining our understanding of less conspicuous facets of the learning of iteration as well as possible pedagogical strategies to strengthen metacognitive skills

An Exploratory Study of Students' Mastery of Iteration in the High School

Although a number of studies report about novices\u2019 diffi-culties with basic flow-control constructs, concerning both the under-standing of the underlying notional machine and the logical connectionswith the application domain, this issues have not yet been extensivelyexplored in the context of high-school education. As part of a projectwhose long-run goal is identifying methodological tools to improve thelearning of iteration, we analyzed how a sample of 164 high-school stu-dents\u2019 approached three small programming tasks involving basic loopingconstructs, as well as two questions on their subjective perception of dif-ficulty. If, on the one hand, most students seem to have developed aviable mental model of the basic workings of the underlying machine,on the other, dealing at a more abstract level with loop conditions andnested flow-control structures appears to be challenging. As to the impli-cations for teachers, the results of the analysis suggest that more effortsshould be addressed to develop a method for testing the conjecturesabout program behavior, as well as to the treatment of loop conditionsin connection with the problem statement

Aquatic Angiosperm Transplantation: A Tool for Environmental Management and Restoring in Transitional Water Systems

Since the 1960s, the Venice Lagoon has suffered a sharp aquatic plant constriction due to eutrophication, pollution, and clam fishing. Those anthropogenic impacts began to decline during the 2010s, and since then the ecological status of the lagoon has improved, but in many choked areas no plant recolonization has been recorded due to the lack of seeds. The project funded by the European Union (LIFE12 NAT/IT/000331-SeResto) allowed to recolonize one of these areas, which is situated in the northern lagoon, by widespread transplantation of small sods and individual rhizomes. In-field activities were supported by fishermen, hunters, and sport associations; the interested surface measured approximately 36.6 km2. In the 35 stations of the chosen area, 24,261 rhizomes were transplanted during the first year, accounting for 693 rhizomes per station. About 37% of them took root in 31 stations forming several patches that joined together to form extensive meadows. Plant rooting was successful where the waters were clear and the trophic status low. But, near the outflows of freshwater rich in nutrients and suspended particulate matter, the action failed. Results demonstrate the effectiveness of small, widespread interventions and the importance of engaging the population in the recovery of the environment, which makes the action economically cheap and replicable in other similar environments

An Investigation of High School Students' difficulties with Iteration-Control Constructs

A number of studies report about students’ difficulties with basic flow-control constructs, and specifically with iteration. As part of a project whose long-run goal is identifying methodological tools to improve the learning of iteration constructs, we analyzed the answers of a sample of 164 high school students to three small programming tasks and two questions on their perception of difficulty. The results of the analysis suggest that more teaching efforts should be addressed to the development of a method to approach programming tasks and, more specifically for iteration, to the treatment of loop conditions in connection with the specifications in the application domain

An Exploration of Teachers' Perspective About the Learning of Iteration-Control Constructs

A number of studies report about students\u2019 difficulties with basic flow-control constructs, and specifically with iteration. Although such issues are less explored in the context of pre-tertiary education, this seems to be especially the case for high-school programming learning, where the difficulties concern both the \u201cmechanical\u201d features of the notional machine as well as the logical aspects connected with the constructs, ranging from the implications of loop conditions to a more abstract grasp of the underlying algorithms. As part of a project whose long-run goal is identifying methodological tools to improve the learning of iteration constructs, we interviewed 20 experienced upper secondary teachers of introductory programming in different kinds of schools from a large area in the North-East of Italy. In addition, a sample of 164 students from the same schools answered a survey which included both questions on their subjective perception of difficulty and simple tasks probing their understanding of iteration. The interviews were mainly aimed at ascertaining teachers\u2019 beliefs about major sources of issues for basic programming concepts and their approach to the teaching and learning of iteration constructs. Each interview was conducted according to a grid of 20 questions, informed by related frameworks to characterize teachers\u2019 pedagogical content knowledge and to design concept inventories. In essence, data from teachers and students confirm that iteration is a central programming concept and indicate that the treatment of conditions and nested constructs are major sources of students\u2019 difficulties with iteration

Very high energy gamma-ray observation of the peculiar transient event Swift J1644+57 with the MAGIC telescopes and AGILE

Context. On March 28, 2011, the BAT instrument on board the Swift satellite detected a new transient event that in the very beginning was classified as a gamma ray burst (GRB). However, the unusual X-ray flaring activity observed from a few hours up to days after the onset of the event made a different nature seem to be more likely. The long-lasting activity in the X-ray band, followed by a delayed brightening of the source in infrared and radio activity, suggested that it is better interpreted as a tidal disruption event that triggered a dormant black hole in the nucleus of the host galaxy and generated an outflowing jet of relativistic matter. Aims. Detecting a very high energy emission component from such a peculiar object would be enable us to constrain the dynamic of the emission processes and the jet model by providing information on the Doppler factor of the relativistic ejecta. Methods. The MAGIC telescopes observed the peculiar source Swift J1644+57 during the flaring phase, searching for gamma-ray emission at very-high energy (VHE, E > 100 GeV), starting observations nearly 2.5 days after the trigger time. MAGIC collected a total of 28 h of data during 12 nights. The source was observed in wobble mode during dark time at a mean zenith angle of 35 degrees. Data were reduced using a new image-cleaning algorithm, the so-called sum-cleaning, which guarantees a better noise suppression and a lower energy threshold than the standard analysis procedure. Results. No clear evidence for emission above the energy threshold of 100 GeV was found. MAGIC observations permit one to constrain the emission from the source down to 100 GeV, which favors models that explain the observed lower energy variable emission. Data analysis of simultaneous observations from AGILE, Fermi and VERITAS also provide negative detection, which additionally constrain the self-Compton emission component