Abstract:

Observation of the properties of minerals, a new teaching material in the science class of school education, was practiced and its effectiveness was confirmed. One of the minerals, calcite, attracts children's interest because the image seen through it appears double. This is because the angle between the two light beams (normal light and anomalous light) in the birefringence of calcite is the largest among the minerals. The method developed by the author for the birefringence of calcite was implemented as a class to evaluate changes in scientific concepts in high school. A laser pointer emitting 405 nm violet light was used as the excitation source for the emission. Calcite crystals were placed in “quercus water“ and the green fluorescent light traces were observed. This method visualizes both incident and transmitted light before and after calcite passes through the “quercus water”, and has not been realized before. The purpose of applying this new method in the classroom is to better equip students with scientific concepts about the phenomenon of birefringence. In the class, after observation students discussed several features of the birefringence phenomenon of crystals. In this study, the assessment of students' scientific concepts was analyzed using the concept mapping method and the discussion conversation protocol. In concept mapping, changes in the number of words (labels) related to birefringence and changes in the connections between words in the students' concept maps before and after the class were statistically analyzed using the Fisher's exact test. In addition, in the conversation protocol, we analyzed in detail the formation of scientific concepts based on the changes in the words used. The results revealed that students' scientific conception of birefringence increased significantly. This is an effective method of teaching science in school not only as an opportunity to arouse students' interest in minerals at junior high and high schools, but also to help them understand the birefringence of calcite correctly. For elementary school students as well, it is an effective method for teaching minerals.

Keywords:

Science education, mineral, calcite, new teaching method, secondary school, junior school, birefringence, fluorescence emission.