Evaluation of the Effects of Medium of Instruction on the Science Learning of Hong Kong Secondary Students: Performance on the Science Achievement Test

Abstract This paper is the first of a series of articles reporting the findings of a longitudinal study on the impact of a new language policy about the medium of instruction on science learning of secondary students in Hong Kong. This paper compares the science achievement of Chinese students learning science through a second language, English, with that of students receiving instruction in their mother tongue, Chinese. Based on the scores on a science achievement test made up of multiple-choice and free-response questions, the English-medium students, despite their higher initial ability, were found to perform much more poorly than their Chinese-medium peers. They were particularly weak in problems that assess understanding of abstract concepts, the ability to discriminate between scientific terms, and the ability to apply scientific knowledge in novel or realistic situations. This result implies that the English-medium students were handicapped in science learning by their low levels of English proficiency, and learning English as a subject through the primary years is not sufficient to prepare them for a full English immersion program in secondary school.