In this research, the change of Korean middle-school science education environments is investigated through analyzing eighth graders’ survey data collected over the past 20 years of TIMSS. We extracted educational context variables that provide meaningful information on changes of Korean science education, and have been surveyed more than 3 study cycles up to TIMSS 2015. The selected educational context variables include school resources and school climate from the school principal’s questionnaires, and teacher characteristics and instructional activities from the teacher’s questionnaires. For each context variable, we analyzed its trend over TIMSS cycles, and discussed its implications in light of Korean educational policy and curriculum changes. Based on the results, we recommended several ways that help to improve science teaching and learning in light of lab assistants, computer availability, teacher learning community, and middle school Earth science curriculum

Introduction
 Methods
 Results and discussion
  1. School resources and school climate
   1) Schools’ science laboratory and assistant forscience experiments
   2) School emphasis on academic success
   3) School discipline problems
  2. Teacher characteristics
   1) Gender of science teachersPercent of students taught by female scienceteachers for each TIMSS study cycle is shown inTable 7.
   2) Teacher participation in professional developmentin science
   3) Teacher collaboration activities with colleagues
  3. Instructional activities
   1) Computer activities during science lessons
   2) Percentages of students taught TIMSS Earthscience topics
 Conclusion
 References

• Youngsun Kwak(Department of Earth Science Education, Korea National University of Education) Corresponding author