The authors present a multidisciplinary path to light, built with a deep and demanding division of labor, with respect for the methodological characteristics of the different disciplines. Based on the shared and participatory observation of natural phenomena present in the daily experience, they guided the students to perform optical experiments to observe and describe the phenomena that had been observed in a controlled environment, and also to interpret them with the language of geometry. The work was enriched by the design and creation of tools, also essential from a historical point of view: a “doing” that requires “knowledge” to acquire “new knowledge”.
The path to light began at the end of the school year 2020-2021, where we asked students to pay attention and possibly photograph during the summer holidays 2021 situations where light is the main character, such as shadows, reflection of landscapes or of objects on water or on mirrors, the colors of the sky, the rainbows, … We also asked them to choose a light effect that had particularly aroused their interest or curiosity, and to describe it, without giving an explanation.
When they returned to school after the summer holidays, the photographs, observations, and descriptions of the children were shared; with our guide, the children recognized the common aspects of the photographs, identified some phenomena and formulated questions.
At the end of this phase of the work, we focused our attention on the following phenomena: light propagates in a rectilinear way; the light reflects; light changes direction as it passes from one transparent medium to another, that is, it refracts; white light is broken down into components of different colors; the sky, blue during the day, assumes different colors, especially at sunrise and sunset.
The study of these phenomena and the answer to the questions that arise from their observation have guided the work of the sciences in the first months of the school year. In the different phases of the path in the Technology lessons, the students designed and built many of the tools and equipment used for the experimental activities.
At this link there is photographic documentation of the activities carried out in the Technology Laboratory.
Light propagates by rays: shadows and dark spaces
Some photographs collected by the boys during the summer showed pictures of the areas of shadow and light forming in different situations.
In the laboratory, we have therefore taken into account the formation of shadows that are projected on a screen when an opaque object is illuminated by a point source and subsequently by an extended source. In particular, we observed and compared the shadows cast on a wall, first illuminating an obstacle with the light from a small LED flashlight and then illuminating the same obstacle with the light emitted from the screen of an iPad.
To explain the formation of shadow and penumbra, we have highlighted the fact that what it e.g. can be seen when sunlight filters through clouds or branches of a forest, it is reasonable to believe that light propagates in a straight line; in other words, that it is reasonable to adopt the model of the light rays.
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Giacomo Bella (Mathematics and science teacher),
Nicola De Bei (technology teacher),
Chiara Mazzeo (Mathematics and science teacher)
by “A. Mandelli” in Milan.
The activity described was performed in third grades during the school year 2021-2022 and was shared in the Science Research Group “Educare Insegnando” promoted byThe association “The educational risk” and coordinated by Maria Elisa Bergamaschini and Maria Cristina Speciani)
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