The reasoning abilities to be expected of the concrete operational and formal operational student, the percentage of secondary science students that are capable of each type of reasoning pattern, and effective strategies to teach science to concrete reasoners are described. Implications for curriculum development are discussed. (KR)

Describes a study which was designed to determine the effect of a 25-hour introductory qualitative analysis course on high school students' understanding of formal concepts related to electrolytes. Suggests that introductory concrete experiences better prepare students to deal with more formal abstract concepts. (TW)