This study sought to determine the effect of using Filipino as a medium of instruction in teaching Science to the achievement of Grade VI pupils of Kasibu Central School, Kasibu District, Kasibu, Nueva Vizcaya SY 2003-2004.

To attain the above objectives, the study made use of the quasi-experimental method. The experimental research method aimed to ascertain the effectiveness of using Filipino as a medium of instruction in teaching Science among the Grade VI pupils in Kasibu Central School.

The study was conducted at Kasibu Central School, Kasibu District, Kasibu, Nueva Vizcaya.

The subjects of the study were the Grade VI pupils of the Masigasig and Masipag sections who were officially enrolled at Kasibu Central School for the school year 2003-2004. The Grade VI Masigasig was the Experimental Group and the Grade VI Masipag was the Control Group. Sixty-nine (69) pupils from the two sections of Grade VI served as the subjects of the study.

The study found out that the use of Filipino as a medium of instruction is more effective in teaching Science than the traditional use of English to Grade VI pupils at the Kasibu Central School.

Hence, the study forwards recommendation that Filipino language should be used as a medium of instruction in teaching complicated Science concepts and theories so that the learners could understand better the lessons being introduced by the teacher.

To enhance the achievement of Grade VI pupils in Science in the study site, the use of Filipino coupled with effective and responsive teaching strategies and methodologies, should be more intensified. The identification of other strategies should likewise be undertaken by Science teachers through the motivation of their school administrators.

Thesis (Master of Education in Science Education - General Science)

Includes appendices and bibliographical references