Abstract:
Education of the 21st century guarantees its students to have critical thinking skills. The product development of teaching material aimed to improve critical thinking skills. The teaching material is expected to be practical and effective in achieving learning goals. This research aimed to develop mangrove-type teaching material and describe the developed teaching material to improve critical thinking skills. The research model was a formative evaluation model developed by Tessmer (1993). The research subject included five tenth grade students of Plantation Agribusiness class for a small test and fifteen tenth grade students of Plantation Agribusiness class for a field test. The data were analyzed using descriptive and categorization techniques. The expected effectiveness result for the small trial, the average pre-test score without using mangrove as teaching material, was 20. The posttest work after using mangrove as teaching material was 78,08 on average. The field test actual effectiveness was N-gain with problems at 0,84 in high category, hypothesis at 0,83 in high category, data collection at 0,74 in high category, data analysis at 0,73, and conclusion at 0,79 in the high category. The conclusion was the teaching materials developed are effectively used to improve critical thinking skills because they can enhance learning outcomes by an average of 58.08.
