Developing and piloting a teaching/learning unit on similar triangles using DGS. (c2010)

Abstract

Technology has recently become a vital factor in the teaching of mathematics. Yet, a key issue remains how technology could be ultimately used to support students in reaching a better understanding of Mathematics and to design meaningful learning experiences. In Geometry, forms of software known as Dynamic Geometry Software (DGS) are shown to be useful in realizing such a purpose. In an attempt to examine the possible effects of DGS on a learning situation, a learning/teaching sequence on Similar Triangles was developed then piloted and clinically analyzed to investigate its effect on a pair of 8th grade Lebanese students' learning and problem solving strategies. The aim was to assess the effectiveness of DGS on students' learning of the topic (9th grade level in the Lebanese curriculum) and the transfer of knowledge and competencies into a computer-free environment. An interview with a 9th grade math teacher was conducted to investigate the difficulties faced in teaching and learning Similar Triangles. The teaching/learning sequence was implemented over a period of 5 sessions each lasting for 1-2 hrs, including solving problems in a clinical interview setting. The sessions were videotaped and transcripts were generated. Data analyzed were collected from the curriculum text, textbook, transcript of the teacher's interview, videotapes and transcripts of the teaching/learning sequence and conducted clinical interviews, students' computer files and solutions to the activities in worksheets and diagnostic and summative tests. The comparison of the diagnostic and summative tests showed that meaningful learning took place and knowledge was gained. The analysis of the clinical interviews highlighted the fact that DGS helps in reinforcing a wide variety of skills and evolving mathematical problem strategies, and that those skills would be transferred into a computer-free environment. The study brought forth that properly designed tasks based on constructivist approach and supported by DGS can help in reaching better learning of mathematics and acquisition of essential mathematical skills at an earlier level than expected in the curriculum.