A simple device observing sounds of rain was developed to correlate the subjective senses of pupils for sounds of rain with objectively measured raindrop sizes and rainfall intensities. In this device, raindrops impact a stainless steel sheet of 2 mm in thickness, and the impact sounds of raindrops are recorded using a portable media player and a stereo condenser microphone. An outdoor experiment to let water droplets of 2.1–5.4 mm in equivalent spherical diameter dropped from a height of 13.2 m collide with the device was conducted. The experiment demonstrated that the impact sounds of water droplets clearly increased with an increase in their diameter. In addition, a school laboratory experiment in which water droplets are dropped from a height of 1 m was conducted. The experiment showed similar results to those of the outdoor experiment. We concluded, therefore, that it is possible to utilize our device as a teaching and learning material that recognizes the differences in raindrop size.

We carried out an educational experiment to test if mortar pieces aid in the understanding of rock weathering through freezing and thawing. We applied pieces of mortar instead of Shikotsu welded tuff, which has been problematic in terms of mechanical strength. We employed two different methods of preparing the mortar pieces: cutting mortar with a diamond cutter, and pouring mortar into a silicon sheet form. Half of the respective mortar pieces were soaked in water. After freezing and thawing of the pieces, we examined their breaking loads. We found that the breaking loads of the wet pieces made with the cutter were indistinguishable from those of the dry pieces. On the other hand, in the case of those mortar pieces made with the silicon sheet form, clear difference were demonstrated between the breaking loads of wet pieces and dry ones. Thus, we concluded that mortar pieces made with a silicon sheet form are fit to use in this experiment.

The purpose of this research is to assess knowledge of the textures of igneous rocks and the ability to identify hand specimens of igneous rocks among high-school students. Ninety students were asked about textures and rock types for two sketches of igneous rocks, namely the equigranular texture of plutonic rock and the porphyritic texture of volcanic rock. Among the students tested, 98.9% of them answered correctly for rock types and 84.4% of them answered correctly for texture names. In addition, they were asked about rock types, namely whether plutonic or volcanic for a hand specimen of granite (polished or unpolished) or for a photograph of granite. Among 30 students, 53.3% answered correctly for polished granite, 33.3% for unpolished granite, and 40.0% for the photograph of granite. These findings exhibited that students successfully acquired knowledge of the textures of igneous rocks but that this knowledge did not lead to the acquisition of the ability to identify hand specimens of igneous rocks. It is difficult for students to recognize textures in hand specimens. Thus, the opportunity to observe hand specimens of igneous rocks should be increased in secondary schools, and instruction methods to improve students' ability to identify igneous rocks should be developed.

We developed an educational tool for understanding the importance of viscous resistance of a medium in the sedimentary mechanism. In order to comprehend this importance, a comparative observation of sedimentary structures formed using media with different viscous resistances was conducted. We carried out a practice work for undergraduate students to make sedimentary layers. To examine the effect of the viscous resistance of the media, we applied air, water, and canola(which are transparent with different viscous resistances)as media. A pre-questionnaire survey showed that 10% of 256 students have knowledge of the effect of viscous resistance on the formation of graded bedding. After the study program, the proportion increased to 82%. Thus, our educational tool was shown to be effective in comprehending the importance of viscous resistance on the formation of sedimentary layers.