In this study, we examined the development of teaching materials that can visualize the bactericidal effect of ultraviolet rays by using Escherichia coli as a bioassay. The uniqueness of this study is that a dilution of a non-pathogenic Escherichia coli strain (Escherichia coli DH5α strain) was sprayed from a spray bottle onto agar medium, half of which was covered with aluminum foil, irradiated with ultraviolet rays or sunlight, and cultured at 37°C for 24 hours. In the method of planting Escherichia coli in a medium, the spraying method from a spray bottle had not been used in previous studies. This spraying method was able to achieve an even diffusion of colonies. In addition, by using the area covered with aluminum foil or ultraviolet blocking film as a control, the comparison of the number of colonies with or without ultraviolet rays and sunlight was clarified, and the bactericidal action was visualized and quantified. Moreover, the difference in the amount of ultraviolet rays between sunny and cloudy weather was clearly visualized. The results of practicing the teaching materials developed in this study in a workshop for high school students confirmed that they improved their awareness and understanding the bactericidal action of ultraviolet rays. Furthermore, the results for teachers suggested that the use of his teaching material would be useful in inquiry activities.

“Structure and Function of the Animal Body” in junior high school science, students learn about the physical and chemical digestion of food, along with the absorption of nutrients. Understanding the processes of digestion in organisms is crucial as it involves changes in the particles of matter. However, during experiments on digestion, students often find it challenging to comprehend the size of particles passing through the membrane of the small intestine. In this study, we have developed teaching materials that enable us to understand the functions of digestion by converting food and nutrients into particles, allowing us to grasp their size and functions. We have also verified the effectiveness of these materials. To aid in comprehending the size of substances before and after digestion, we created a model using connected beads to represent macromolecules. Furthermore, to elucidate the mechanisms of digestion, absorption, and synthesis in the human body, we designed disassembly and assembly activity teaching materials using blocks. A class practice was conducted to verify the effectiveness of these teaching materials. As a result, approximately 80% of students were able to understand the function of digestion, and it notably improved their understanding of molecular dimensions. Based on these results, it is evident that these teaching materials significantly help students comprehend the function of digestion in terms of the concept of particles.

For university students majoring in life science and medicine, it is important to understand the function of organs in animals. Although frogs and crayfish are suitable materials for anatomical education, previous anesthesia protocols have several drawbacks in terms of safety and usability. In addition, obtaining Procambarus clarkii (red swamp crayfish) that has a large body, suitable for anatomical education, is becoming increasingly difficult, partly due to recent changes in regulations regarding alien species in Japan. In this report, we established dissection procedures of Rana catesbeiana (bullfrog) and Pacifastacus leniusculus (signal crayfish) with improved anesthesia protocols, which are relatively easy, safe, low-cost, and sufficient for anatomical education. The improved anesthesia protocols facilitated preservation of functional organs, which helps students to understand the morphology, arrangement, and relationships of the digestive, circulatory, genitourinary, and nervous organs.