A great deal of research has been done regarding science in-service education and the conclusion can be drawn that positive results were generally achieved in workshop-participant attitude and implementation of instructional approaches into the classroom. One of the most important effects of an in-service workshop is upon the students of the teachers participating in an in-service program, but rarely, if ever, is this parameter assessed in the in-service evaluation design. This study investigated the relationships among (1) teacher's attitudes and implementation of in-service workshop developed science materials (learning cycles) and (2) elementary school student's conservation reasoning and language used to describe properties of objects. Data were gathered from over 100 students from grades K-5 and 16 teachers who had participated in an in-service program. A representative comparison group of students and teachers was selected which generally matched the teachers participating in the in-service workshop except for one variable–-the comparison group taught science traditionally, that is, by exposition. Data from the research indicated that the teachers involved in the science in-service workshop implemented the workshop-developed learning cycles into their science classes. Significantly greater gains in conservation reasoning and language usage occurred with the students of the teachers participating in the science in-service workshop as compared to students in the exposition classrooms.