Din Yan Yip

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.

Teachers' concerns on school-based assessment of practical work

The Teacher Assessment Scheme (TAS) is a form of school-based assessment that has recently replaced the external practical examination in AL Biology of Hong Kong. This study aimed at understanding the problems encountered by teachers in implementing this innovation. Over 300 teachers expressed their concern about different aspects of the TAS in a questionnaire of 25 items and two open-ended questions. The responses showed that the teachers were deeply concerned about the lack of resource materials and training, as well as the heavy workload involved in designing and assessing practical activities for their students. Other key concerns included the impact of the scheme on student learning, the fairness of school-based assessment, and the need for a critical review on the implementation of the scheme. However, the teachers had a relatively low level of concern on their role in revising or improving the scheme. This paper also considers whether the levels of concern in different areas might change as the teachers gain experience in TAS.

Children's misconceptions on reproduction and implications for teaching

Studies on misconceptions developed by children after instruction are important in revealing their difficulties in conceptualizing scientific knowledge and suggesting ways of remedy. This paper pro...

Alternative Conceptions in Biology-Related Topics of Integrated Science Teachers and Implications for Teacher Education

This paper reports a study of the alternative conceptions held by junior secondary science teachers enrolled in an in-service teacher training program. The subjects completed a written instrument which probed their understanding of biological concepts in the integrated science curriculum. The subjects, particularly the nonbiology graduates, were found to show serious misunderstanding in concepts concerning diversity of life, photosynthesis and respiration, reproduction, and detecting the environment. This finding supports the assertion that our science teachers, being graduates in specific areas, are inadequately prepared to teach a broad and balanced junior science curriculum. To strengthen the subject matter knowledge and pedagogical skills of prospective and practicing junior science teachers, a number of provisions are suggested for teacher training programs, undergraduate science courses, and school-based activities.

The Subject Matter Knowledge in Physics Related Topics of Hong Kong Junior Secondary Science Teachers

The subject matter competence in physics related topics of 147 inservice junior secondary science teachers in Hong Kong was identified using a true-or-false instrument based on a framework conceptualized by the authors. The findings of this study showed that teachers are weak both in factual knowledge and conceptions in these topics. Although physics majors outperform nonphysics majors significantly in the test, their own performance is by no means satisfactory on criterion referenced terms. Items incorrectly answered by over 40% of the teachers are listed with corrections given. The sources of conceptual mistakes and specific remedial measures were elaborated for items incorrectly answered by more than 60% of the teachers. General implications and possibilities for improvement in tertiary education, science teaching, and teacher education were discussed.

Developing a Better Understanding of the Relationship Between Transpiration and Water Uptake in Plants

Performance on a multiple-choice item in a public examination indicates that most students do not understand the principle of the bubble potometer and its limitations in measuring transpiration rate. Teaching strategies are suggested to overcome these problems by helping students to compare the bubble potometer with the weighing method, develop the concept of assumptions, and resolve cognitive conflicts. To rectify the alternative conception on the role of transpiration, an interactive activity is designed to guide students to expose their preconceptions, design investigations to test them and evaluate the validity of the original ideas.

Assessing the concept of controlled experiments in science teachers

Biology teachers, attending a post-graduate training course, were given a written test in which they had to identify the controlled set-up in two different experiments. A teaching strategy was designed to help the subjects to construct and consolidate an understanding of controlled experiments, in line with scientific inquiry methods, by following the process of hypothesis, formulation and testing.

Assessing and Developing the Concept of Assumptions in Science Teachers.

The practical work of the Hong Kong A-level biology course has been dominated by recipe-type activities. This can be related to the inadequate knowledge and skills of the teachers in teaching investigative work. Based on the responses to a written test, the present study indicates that most of the biology teachers attending a post-graduate teacher education course demonstrated a poor understanding of the notion of assumptions and could not evaluate experimental evidence with reference to the assumptions made. By using small-group and whole-class discussions with guiding questions, the teachers were able to construct successfully the concept of assumptions and develop a better appreciation of the nature and limitations of the process of scientific inquiry.

Investigations with protease

Two simple and reliable ways for measuring protease activity are suggested which can be used for a variety of investigations for both lower and upper secondary biology classes