1998．第26卷第1期（Vol. 26 No. 1）．pp. 101116
Alternative Conceptions on Excretion and Implications for Teaching
Research on children's understanding of science subject matter shows that students develop alternative conceptions for a number of reasons. This paper illustrates how such knowledge can be used to improve the design of classroom instruction. Students' problems in understanding the concept of excretion are probed with a multiple-choice item followed by an interview. The results suggest that understanding may be promoted by using instructional strategies that build on students' existing knowledge, elicit conceptual development, discriminate the use of everyday language in a scientific context and establish meaningful connections between new and old concepts.