The formation of precipitation, which is produced by mixing a metal ion solution with a solution of reagent, is hard to observe in a test tube, as precipitation immediately occurs and forms a lump. In classroom experiments focusing on precipitation at senior high school, a problem has been the overuse of reagent. As some gaseous materials evaporating from its solution are harmful to health, the smallest possible amount of reagent has to be used. The author had already reported that salt crystals produced by the reaction of acid gas with alkaline solution can be observed through the microscope. In this study, the author will report that the formation and process of precipitation can be observed easily with a CCD camera attached to a microscope. This article deals with the practice at university and its application at senior high school using the proposed method. The reaction of limewater with carbon dioxide was carried out at university, and the students were interested in observing the formation and dissolution of calcium carbonate precipitation. As an application of the proposed method, the reaction of metal ions with ammonia and hydrogen chloride will be practiced at senior high school. The formation and dissolution of each precipitation will be observed with greater interest.

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The following findings resulted from continuous measurements of the number of metacognitive strategies of pupils learning multiplication tables by using a metacognitive strategy measurement tool in the second grade of elementary school (Sakamoto, 2010). 1) There is a tendency for the number of metacognitive strategies to decrease with time. 2) Pupils who do not use metacognitive strategies from the beginning still show the tendency of not using them with the passage of time. 3) In the context of problem solving associated with memory, pupils gradually show a tendency of not using the metacognitive strategy related to control and planning with the passage of time, but they use a metacognitive strategy related to monitoring continuously. Thus, it is suggested that it is educationally significant to periodically measure the number of metacognitive strategies.

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The present study examined students' knowledge after learning the first type of quadratic inequality, ax^2+bx+c>0, a>0, D>0 (D=b^2-4ac). The study also looked at the difference between students with more prior knowledge about the functional approach (high students) and students with less prior knowledge about it (low students). The results showed that most students had knowledge about solving the quadratic equation, but more high students were able to draw the graph than low students. This study also shows that 73.9% of all students acquired strategies with which they could get only answers about specific types of quadratic inequalities, and that there was no difference between high and low students regarding the acquisition of these strategies. The instructions regarding quadratic inequality are also discussed.

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This research aims to clarify the purpose of incumbent teachers' use of the "Rika network". First, a factor analysis was performed for the questions of which the standards concerning the "Rika network" use were composed. The factor analysis produced four factors. The first is "Clarification and fixed of content of study". The second is "Specification of learning task and extending the perspective of observation". The third is "Support of experimental observation and manufacturing technology". The fourth factor is "examines study of learners". These four viewpoints reflect the intention and motive for differentiating among the school kind, the class place, and the class form. Subsequently, a factor decentralized analysis was done by using the mean value of the obtained factors to examine a target difference by the number used. The result showed that there is a difference in the purpose depending on the number used in the 1st, 2nd, and the 3rd factors. The difference appeared mainly when "Once" or "5-6th times" were used.

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