Using the knowledge of penumbra with a trick simulation

Due to their peculiar nature, shadows and holes are a promising source of insight about the representation of physical objects in cognition. The article investigates the extent to which shadows and holes are represented as object-like.

We investigated the ideas of children for the propagation of light, shadows, mirrors lenses. We found in some questions differences between boys and girs The ideas we investigated related to the following phenomena: • Shade formation • Darkroom-pinhole camera • Reflection of light • Refraction of light • Properties of Lenses • Creation of virtual images from plain mirrors, lenses. These ideas are interrelated. For example, the child's idea of shadow formation is related to the idea that the student has of light. a) Formation of shadows Ravanis and Papamichael (1994) described four forms of representation for the natural causes of the formation of shadow: 1. The shadow of an object is considered to be due to the object, but also by an external cause in relation to the object, for example the night, the shadows of trees, etc. 2. The shadow is due to the object without any relation to the light and without doing any prediction of where the shadows will be formed.

2008

The purpose of the study was to "film" the conceptual development of students as they were studying the optics of shadows and mirrors using lesson materials which were developed by the Constructing Physics Understanding (CPU) group of Dr. Fred Goldberg of San Diego State University. The materials were adapted for use in the Philippines. The CPU materials include a learning cycle consisting of elicitation of preconceptions followed by concept development activities and finally an application phase. Development of student conceptions could be followed through worksheets, the individual idea journal, transcribed videotaped small group discussions, and individual interviews. The sample was formed by three students of a class of 31 students. The results show that it is indeed possible to describe conceptual development in detail and this description will be provided in the paper. In spite of having only experience with superficial and memory oriented courses in High School, the...

The vertical length of the shadow cast by a vertical object on a vertical screen was investigated. The distance between the screen and the light source which was placed at ground level, was kept fixed throughout the experiment. The distance between the object and light source was varied by moving the object away from light source and towards the screen. It was predicted that as the object moved away from the light source and towards the screen, its shadow size would decrease from infinity to the object height. This prediction was verified by the experimental data using a log-log graph which generated a linear plot with the measured slope and y-intercept matching very closely with the predicted values.

This is created by me based on my experiment

Perspective as Practice, ed. by S. Dupré, 2019

This chapter is an exploration of the optical sources used by Leonardo da Vinci on his research on shadows. As most sources of the Renaissance were available in Arabic and Latin, the focus is mainly on translation and knowledge transmission. Leonardo research in light and shade is well known in architecture and art history, because shadow is directly involved in the rendering of the volume and depth. Leonardo is also well known to historians of optics, because he provided one of the very first studies of the "penumbra"—well before Maurolico (1521) and Kepler (1604). However there is evidence that Leonardo used external sources for the geometrical analysis of the penumbra. This chapter reviews the medieval optical sources he could use to compose his notes. A careful study of Leonardo’s notes reveals that they were probably translated from a scholastic disputation on optics, akin to the works of the late 14th century Parisian school. Information is provided for future identification of this treatise.

Review of Science, Mathematics and ICT Education, 2017

This paper aims at exploring children's ideas concerning shadow formation as they are expressed through their drawings. A qualitative research approach was adopted using two sets of data (89 drawings in total) collected over a period of 6 months in two kindergartens, one in France and a second in Greece. The drawings in each group were realised using similar instructions defined jointly by the team of researchers. The indicators that were used to analyse the drawings can be aggregated in four categories: presence of the three entities needed to represent the phenomenon of shadow formation, shadow characteristics, alignment, and nature of light. Results are presented not with the intention of comparison of the two groups, but with the disposition of highlighting the diversity of categories that emerged. Findings and educational implications for science at kindergartens are thoroughly discussed. Keywords Physics learning, preschool, formation of the shadows, early science education, drawings 56 Alice Delserieys, MAriA-AntoniettA iMpeDovo, GlykeriA FrAGkiADAki, MAriA kAMpezA résumé Cet article vise à explorer les idées des enfants concernant la formation des ombres telles qu'elles s'expriment dans leurs dessins. Une approche qualitative a été adoptée. Celle-ci s'appuie sur deux séries de données (89 dessins au total), recueillis pendant une période de 6 mois dans deux écoles maternelles en France et en Grèce. Dans chaque groupe, les dessins ont été réalisés sur la base de consignes similaires, définies conjointement par l'équipe de chercheurs. Les indicateurs utilisés pour analyser les dessins peuvent être regroupés en quatre catégories: présence des trois éléments nécessaires à la représentation du phénomène de formation des ombres, caractéristiques de l'ombre, alignement, et nature de la lumière. Il ne s'agit pas, ici, de comparer les deux groupes, mais de mettre en évidence la diversité des catégories émergeant de l'analyse des dessins. Les implications en matière d'éducation scientifique à l'école maternelle sont discutées.

American Journal of Orthodontics and Dentofacial Orthopedics, 2011

2.-Classification of materials depending on how much light can get through them 2.1 transparent 2.2 opaque 2.3 translucent 3.-How we see things 3.1 light enters the eye 3.2 how the eye works 4.-Reflection 4.1 how light is reflected in a mirror 4.2. classification of materials depending on how different surfaces reflect light 4.2.1 shiny surfaces 4.2.2 dull surfaces 4.3 flat and curved mirrors 4.4 differences between shadow and reflection