This paper describes the procedure of developing an instructional tool, "concept mapping" and its effectiveness in making the material meaningful to the students. In Pakistan, the traditional way of teaching science subjects at all levels at school relies heavily on memorization. The up-to-date data obtained from qualitative and quantitative research strongly supports the value of concept mapping as an instructional tool both for cognitive and affective gains. This study seeks to contribute to this development by considering how the insights of Ausubel can be converted into an effective and efficient instructional method. It was found that concept maps help improving achievement of the students and make learning more meaningful so that retrieval is possible.