Modeling Tasks for Exploring Topics of High-School Biology in the Computer-Supported Educational Environment ‘ModelsCreator’ Vassiliki Zogza, Marida Ergazaki, Vassilis Komis Department of Educational Sciences and Early Childhood Education University of Patras, Greece zogza@upatras.gr, ergazaki@upatras.gr, komis@upatras.gr Abstract. Τhis paper reports on part of our work for the project ‘ModelsCreator’ in regard with the didactic approach of specific topics within the secondary biological education. Considering the already reported difficulties of high-school students in adequately grasping complicated biological processes of abstract nature such as photosynthesis or inheritance, we developed corresponding educational scenarios within the computer-supported environment ‘Models Creator’ to be implemented in experimental as well as in real classroom settings. The development of these scenarios which include a series of modeling tasks organized in students' worksheets is discussed here. Keywords. Computer-Supported Modeling, High-school Biology, ‘ModelsCreator’, Plant growth, Photosynthesis, Inheritance. 1. Introduction A number of computer-supported educational environments have recently been developed in a ‘socio-constructivist’ theoretical framework ([4], [18]) with the aim of supporting the teaching and learning process in a qualitatively different way ([5], [10]). Such environments attempt to give students the opportunity to express, explore and refine their mental representations about natural phenomena by providing them with appropriately designed building and testing tools ([17]). Thus, computer-supported dynamic modeling is employed in order to facilitate students’ active engagement in a process of integrating specific parts of knowledge into broader explanatory or merely descriptive mental structures ([15], [16]). ‘ModelsCreator’ is a computer-supported educational environment that - apart from purely qualitative or purely quantitative approaches to the natural world, such as concept maps or mathematical models- allows for semi- quantitative modeling as well as for modeling with logical operands (i.e. IF, AND, OR, THEN) (http://www.ecedu.upatras.gr/modelscreator/ ). It practically constitutes an ‘open’ modeling environment where students are supposed to analyze problems in terms of ‘objects’ relevant to the problem, ‘properties’, that is factors characteristic of these objects and finally ‘relationships’ between the ‘properties’ of one or more ‘objects’. The type of ‘relationships’ actually defines the type of modeling. In case of using semi- quantitative reasoning, namely mathematically informed ‘relationships’ of qualitative character, students are able to construct semi-quantitative models, while when using logical operands they can come up with models of logic. In this paper, we present two educational scenarios we developed for the environment of ‘ModelsCreator’. The first one, ‘Photosynthesis & Plant Growth’, focuses on photosynthesis not only as a biochemical process, but also as an essential parameter of plant growth and engages students in the construction of semi-quantitative models. On the contrary, the second one, ‘Inheritance’, requires the construction of models of logic having to do with the way that dominant or recessive genes located on autosomic or sex chromosomes pass from parents to offspring. The questions to be highlighted for both scenarios hereafter are: • Which is the theoretical background for developing each educational scenario and which are the aims of it? • Which are the suggested modeling tasks within the environment of ‘ModelsCreator’ and which are the underlying didactic objectives? 2. The educational scenario of ‘Photosynthesis & plant growth’ Research on students’ expressed models about photosynthesis and plant nutrition has