Vol. 117 No. 3 (2021)

A structural perspective of groups of four atoms of the s and p block elements is presented, with the help of a continuous shape measures (CShM) analysis. Among the shapes of a group of N points, defined by 3N Cartesian coordinates, the reference shapes are regular polygons and polyhedra, together with univocally defined combinations thereof (e.g., two coplanar or perpendicular edge-sharing squares). This study classifies most of the structures either by their closeness to a regular shape, or by quantifying their positions along minimal interconversion pathways between two regular shapes. The many shapes described by a given pathway are generically grouped as a molecular conformation.

Keywords: Shape measures, stereochemistry, ring conformation, polyhedra, molecular structure, clusters.

This paper presents the main features of the «Educational Innovation in Physics and Chemistry during Pandemic Times Awards» driven by the Specialized Group on Didactics and History of Physics and Chemistry of the Spanish Royal Societies of Physics and Chemistry. By the study of the awarded projects, this work offers a wide range of educational resources and didactic experiences of interest for Physics and Chemistry teaching in secondary education. The awarded projects also pointed out the creativity of high school teachers and the diversity of pedagogical methodologies in Spanish classrooms, such as digital tools or homemade experiments. Hence, several educational practices are presented in order to highlight the outstanding work of secondary education teachers during the COVID-19 pandemic.

Keywords: awards for teachers, COVID-19, educational innovation, physics and chemistry, secondary education

We study the ripening of the peach and the evolution of the quantity and characteristics of its pectin. We use healthy peaches at an advanced stage of ripeness and cuttlefish cutlets, to obtain peach candy that preserves the characteristic flavour and fragrancy of the fruit used. We reuse and give value to the surplus production and a residue from two companies located in Cieza (Murcia). We can only find a few homemade recipes to elaborate this dessert, all of them using a high amount of extra gelling agents. We will not find peach candy in shops or supermarkets.

Keywords: peach, pectin, pectil methylesterase, low-methoxyl, calcium bridges

Non-formal education is nowadays recognized as a useful complement to the scientific education that is offered in the school. In this context, this paper presents a brief analysis of the Spanish national curriculum contents for the subjects of Physics and Chemistry, that may be covered while participating in a scientific out-of-school activity, a crystal-growing contest named Concurso de Cristalización en la Escuela (CCE). Results show that the methodology followed in the contest allows teachers to introduce some curricular contents and to present a more accurate view of the nature of science, supporting their students’ scientific literacy.

Keywords: Chemistry education, crystallography, non-formal education, secondary school curriculum, scientific literacy