Jean-François Le Maréchal

Varieties of Labwork: A Way of Profiling Labwork Tasks

If we wish to explore the effectiveness of labwork for achieving its goals, we need to be clear about the aims of each labwork task and be able to describe its essential features in a systematic way. A model is presented of the process of developing a labwork task and evaluating its effectiveness. Two senses of ‘effectiveness’ are identified: the match between what students are intended to do in the task and what they actually do (effectiveness 1); and between what students are intended to learn from the task and what they actually learn (effectiveness 2). A classification scheme is then described which can be used to produce a profile of any labwork task. This provides a useful tool for exploring systematically the effectiveness of labwork tasks.

Memorisation of Information from Scientific Movies

This study deals with students working with a hypermedia that links a bank of chemical movies. Two aspects were examined: (i) the factors (such as surface features) that prevail to the choice of movies by students that use the hypermedia; (ii) the kinds of information that students are able to memorise. The research questions were formulated as (i) How chemical movies are chosen by students who have to answer questions about chemistry? and (ii) How difficult is it to memorise conceptual information from such movies? The films were specifically produced for this research, several of them with two possible narrations: one with a description as perceptible as possible of the pictures of the movie, the other with a maximum of chemical terms. In a first experiment, six pairs of 17-year-old students were given a set of questions to answer with the hypermedia. In a second one, four students were given a series of seven movies to be used, and were questioned after 7 days. The most occurring factors for choosing movies were surface features, but we observed students making their choice after reformulating a question. It also happened that a pair of students chose a movie more than once. Low memorisation seems to occur with movies that display several events, such as chemical reactions. After 7 days, students remembered more pictures of the movie than words of the narration, and from the picture, more icons than animations or photos, and almost no symbols

La mesure dans l'enseignement de la chimie Cas d'une approche des titrages par pH-métrie et conductimétrie

This article takes a look at a scientific approach to measuring based on examples encountered in chemistry class. The method underscores the fact that the volume of the solution studied must be determined prior to the taking of one or more measurements all of which are then studied so that the pupils can obtain a better idea of the solution at hand. This approach allows for the analysis and comparison of 2 basic solutions with one being measured using the pH level and the other using the level of conductivity. The research project is based upon pupil experiment reports and graphs and led to a better understanding of the difficulties encountered by pupils in the case of pH levels. It would seem that the surface characteristics of the 3-D graph plotted by the pupils can lead errors in interpretation and that the difference between the solution studied and a pupil’s idea of it due to the measurements taken cannot rectify this error. This, however, does not hold true in the case of conductivity levels despite the very same difference between solution and idea since the link between solution and idea can be better understood thanks to the surface characteristics of the graphs. This can be best understood using anti-derivatives.