Investigación sobre las concepciones de los estudiantes acerca de los estados de agregación y los cambios de estado

In this work the results of a test based on phase changes and the states of matter are discussed. They show heavy misconceptions in pupils, 15-16 years old, in the first two years of Italian Secondary Upper School. Pupils show best results when they must work with experimental situations but show difficulties to pass from verbal to graphical language

Il problema della comunicazione linguistica a scuola : il linguaggio scientifico e chimico in particolare

In this work first of al1 we notice the importance of linguistic communication at school and we underline the fact that every teacher, regardless of his discipline, has the problem of making himself understood. Then, for what concernes scientific language, we give some methodological directions. Finally we give prominence to chemical language and to the role that this language could have in teaching

Heats of formation of yttrium-antimony alloys

The heats of formation of the Y-Sb system have been,measured using a differential direct isoperibol calorimeter. The following values (kcal (g atom)-1) were obtained for the various compounds (reaction in the solid state at 300 K): Y3Sb, \u394Hfrom = -15.3 \ub1 0.5; Y5Sb3, \u394Hfrom. = -23.0 \ub1 0.5; YSb, \u394Hfrom. = -25.0 \ub1 0.5. The composition and state of the samples were checked by chemical, metallographic and X-ray analyses. The data have been compared with those obtained for the Y-Bi and Nd-Sb systems and discussed briefly. \ua9 1977