Abstract
Elementary astronomy is an integral part of school science education. It is one of the subjects where elementary yet non-trivial observations are easily accessible: hence the subject has a potential to evoke students’ curiosity and to empower them to pursue their questions through methods of scientific enquiry. Astronomy is also important from the scientific literacy perspective because of its connections to astrology.
Visuospatial thinking in astronomy: Elementary astronomy is known to be prone to difficulties and common alternative conceptions for students as well as adults. Although students’ mental models are known to be erroneous, these models have never been studied from the perspective of visuospatial thinking and reasoning.
Mental models in astronomy consist of significant amount of information about spatial quantities (shape, size, distances, patterns of motion) along with information
about other physical quantities (temperature, gravitational force). Explanations of common astronomical phenomena such as day-night, seasons and phases
of moon require visuo-spatial transformations such as mental simulation and perspective change.
Spatial tools: We know from the literature that although schematic diagrams are a useful spatial tool, they presents difficulties to students because of their twodimensional, static and abstract nature. Our analysis of existing textbook diagrams and students’ diagrams showed that both of them do not use the explanatory and
predictive power of diagrams. Using the literature on spatial thinking and data on diagrams we developed and tried out a pedagogy for astronomy which heavily relied
on spatial tools for this study. A conjecture is an inference based on inconclusive or incomplete
evidence drawn from literature and the researcher’s experience. Conjecture based design is situated in a real classroom setting rather than in a laboratory setting and
it aims to arrive at new widely applicable instructional strategies. The researchers come up with an initial conjecture, design an instructional method assuming that
the conjecture is true and finally test the effectiveness of their instructional method.
The planned intervention takes place over a significant period of time. As the intervention proceeds, the conjecture evolves and becomes precise and the study is
usually fairly flexible to incorporate the insights gained during the intervention.
The study began with an assessment of astronomical knowledge of students at the end of Grades 4 and 7, from rural, tribal and urban-slum areas in India. This initial assessment was followed by a one-year intervention for around 80 students of Grade 8, spread over 3 contact periods of 15 days each. At the end of Grade 8 post-tests were administered to the ‘treatment group’ and an equivalent ‘comparison group’.
Assessment of astronomical knowledge: We explored Grade 4 and Grade 7 students’ understanding of astronomy in four areas: observations, textbook information, indigenous knowledge and the sun-earth model. We found that although students had observed several astronomical objects and events, they were unable to find and/or represent patterns in celestial phenomena such as path of apparent daily
motion of the sun, moon and the stars. Their observations were qualitative and influenced by visual properties (colour and brightness). Although the majority of students knew standard terms such as equator, orbit, names of planets they possessed alternative models of the earth with major difficulties related to integrating
gravity with spatial properties. Their explanations of simple phenomena such as day-night were erroneous or superficial and they were unable to draw ray diagrams
in simple novel situations such as drawing a shadow of a stick in sunlight. Students were familiar with indigenous knowledge and cultural tools such as luni-solar
calendars, but this knowledge was associated with astrology.
This assessment defined our starting point of our intervention.
Pedagogy: Helping students to construct scientifically accepted mental models, and explaining phenomena on the basis of these mental models was the main aim of the
intervention. Use of concrete models as a pedagogic tool is a well-known practice while teaching astronomy (though it is not so common in India). Advantages of
concrete models are, they are three dimensional, movable and realistic, and hence they form a good starting point. However, they lack the analytical power of diagrams.
From the literature we knew that gestures and actions play an important part in spatial cognition.
The following two interrelated conjectures provided the rationale for design of gestures in our pedagogy:
1. The ‘phenomenon - gesture - mental model’ link: distance and time scales in astronomy being beyond direct perception, actions may provide the most accessible
bridge from the phenomenon to the mental model.
2. The ‘concrete model - gesture - diagram’ link: gestures can be used along with concrete models to make these fluid, and with diagrams to add a third dimension.
Both concrete models and diagrams can be made dynamic with the use of appropriate gestures.
The pedagogic gestures and diagrams were analyzed to identify their significant characteristics. A new scheme of analysis was developed for this purpose. Video data on student’ use of gestures and diagrams was collected during classroom interaction and guided collaborative problem solving sessions. This data also served to identify students’ difficulties and trace their learning trajectories. Through the course of the intervention the initial conjecture was refined and developed, with
continuous inputs from both theory and data. Assessment at the end of the intervention showed that our designed pedagogy and specifically, the novel attempt of
designing pedagogic gestures turned out to be useful.
