In this paper the author has intented to investigate the nature of children's preconceptions and the changing processes of these through the analysis of the science lesson on the water evaporation at the 4th grade in elementary school. The main points arising from this study are as follows: (1) Children's preconceptions take the form of procedural knowledge. (2) When children become aware of the conflict of their preconceptions and falsify them, their procedurally encoded knowledge is tranformed into scientific concepts. (3) When the science teaching fails to envisage the teacher assisting the children to articulate and explore their own procedural knowledge, they coexist their preconceptions with the declarative knowledge presented by the teacher.

J. Piaget, who was a developmental psychologist, had created many genius tasks to pose clinically upon the children subjects during the inquiry into the developmental process of the children's intelligence. Among these tasks, there is one task called class-inclusion task, which means that the extention of a class concept includes all the subordinate concepts. The authors thought that this task could be applicable to other fields of class relations of objects. They applied the task to the living things and intended to investigate the children's abilities of classification. They made some problems similar to the task in a questionnaire form available in the classroom and asked the children to answer in the elementary and lower secondary schools. The data thus obtained were analyzed and interpreted. The main results of this study are as follows: (1) Almost all the elementary school children, from the 4th to the 6th grades, were lacking the basic abilities of the classification of the animals required by the problems. (2) Although they had learned the contents of the biological classification already in the science classroom, at most only 40% of the lower secondary students were able to answer the class-inclusion problems of living things completely. Moreover the percentage of the correct answers of the 8th graders was one half or one-third lower compared with that of the 7th graders. (3) The class-inclusion problems of living things made by the authors proved to be useful for the assessment of the classification abilities of the children from those facts mentioned. (4) These results and the children's responses to the questionnaire seem to suggest much information about the teaching programs and methods in the biology education.

In teaching the general properties and functions of enzyme, it would be very useful to indicate the enzyme activity as a color intensity to students. We have investigated the visualization of the succinate dehydrogenase activity with nitroblue tetrazolium (NBT) in the extracts of chicken breast muscle and yeast from the educational viewpoints. Then, we have tried to measure the color intensity of the sample with a hand-made photometer in which a solar cell has been devised as a photodetector. It revealed that chicken breast muscle was more suitable than yeast as a material for an extract and that NBT was applicable to show the general properties of enzyme in the extract with a visualization method. A hand-made photometer showed a high availability in the measurement of the color intensity of the sample. The instrumentation of a hand-made photometer was also described.

We proposed here the use of polyacrylamide gel (PAAG) films as the teaching tool not only for general enzyme properties but also for the important relationship between enzyme and cell organella. PAAG films have been widely used as a carrier of extracted enzyme, cell organella and whole cells in enzyme histochemistry. As an example of educational use of P AAG films, rat liver mitochondria were incorporated into a PAAG film with the thickness of 100 μm and were examined an optimum staining conditions for the visualization of succinate dehydrogenase activity with NBT. We also investigated suitable preserving conditions for P AAG films. Under optimum staining conditions, the general properties of enzyme were clearly demonstrated with PAAG films. The succinate dehydrogenase activity in PAAG film was well preserved in the mixture of phosphate buffered saline containing succinate and 10 (v/v %) glycerin at -20°C. Rat liver mitochondria could not be recognized clearly in the observation of stained PAAG films by optical microscopy because of the presence of non-mitochondrial particles, judging from their shape and size. It was shown that some improvement was needed for the observation of mitochondria in PAAG films by optical microscopy.

At the secondary school level throughout the world nowadays, there are important issues being considered such as how and when to impose the learning of required science subjects, and when to handle selected learning of separate science subjects. In the German Democratic Republic (GDR), all upper grade students at the secondary school level are bound to take all required science subjects and select some other additional optional subjects in science. This pattern might be given prime attention worldwide. In this research, the author attempted to consider the selection of science subjects at the secondary school level in the GDR. In this study, a survey of the historical circumstances on the subject selection in science in the GDR was firstly made. The existing educational laws, the science subjects studied at the secondary school level, and the issues on studying science subjects were clarified in this study. These results are shown as follows: In the GDR, the present compulsory learning of subjects occupies the greater part of the number of subjects in the "Ten-Year General Polytechnical Secondary School." The "Extended Secondary School," which can be considered to be as good as the "Ten-Year General Polytechnical Secondary School," offers many compulsory learning areas of various subjects as well as compulsory learning areas of science subjects, specifically physics, chemistry and biology. To encourage learning according to the ability, aptitude and occupational interest among the learners, the setting up of "Arbeitsgemeinschaften" was introduced in the upper grades of the "Ten-Year General Polytechnical Secondary School." The inclusion of the optional subject areas, and optional compulsory subject areas was made in addition to the compulsory subjects offered in the "Extended Secondary School." In the GDR, the assumption for finding out the ability and aptitude of students can guarantee the acquisition of common general education of the people. The people could therefore have the option of selecting the pattern of learning according to the ability and aptitude they possess.

It is said that when popguns are given to third graders as a teaching material for the purpose of teaching the elasticity of air, they handle them with keen interest. However, through the survey conducted when they became fourth graders, it has turned out that they did not understand that they had been taught about the elasticity of air. Therefore, in this paper, the authors presumed that their failure to understand the elasticity of air might be attributed to the teaching materials and teaching procedures, and examined the use of the push rod rocket as a more effective teaching material and better teaching procedures. As a result, the following facts have been clarified from the present research: (1) It would be more effective for the pupils' better understanding of the elasticity of air to use the push rod rocket than to use the popgun in the introductory stage of the unit, and then the popgun in the final stage. (2) The popgun made of an empty mayonnaise bottle may become an obstacle to the pupils' process of thinking in understanding the elasticity of air. (3) For the understanding of the elasticity of air, syringes and clyster pumps are effective as teaching materials. (4) A water pistol (a kind of popgun in which water is filled instead of air) should not be used for the experiment of making sure that water cannot be compressed.

In Rika-kyoiku, science education in Japan, at lower secondary schools, it is essential to have students discover a law based on the data obtained by themselves; it is believed that the process is effective for the students to acquire so-called scientific methods. When their teacher leads them to assume a simple mathematical relationship on their data, e.g. a linear one, he has to explain the philosophy which justifies the procedure. Rika-kyoiku, however, has not given an explanation for justifying them. The present report intends to give the explanation satisfying students at lower secondary schools in Japan. In the overall objectives of science at lower secondary schools given in the Course of Study, the following phrase is employed: "to develop students' ability in and positive attitude towards making inquiries about nature." This phrase can be interpreted that the students should acquire the scientific methods: the way of discovering a law which natural science has given its concepts. The students' attitude to Rika, science, primarily depends on the degree of understanding how the law plays its own roles in natural science. Without considering how the law works, an essential discussion cannot be started in Rika-kyoiku. In order to have the students learn the scientific methods, the teachers have to recognize them by themselves; consequently, they also have to understand the ideas according to which the Western people have developed natural science. The required attitude to science surely differs from that of scientists; in fact, they need not necessarily pay attention to those ideas. For the purpose of having the teachers understand those ideas, it is essential for the Course of Study to explain them.

A number of investigations have already reported that students commonly encounter a lot of cognitive errors related to the concept of force. We have conducted a research on students' understanding about force vector on static things. It was found out in our research that students have encountered a lot more difficulty in dealing with attractive force vector than with repulsive force vector. In this research we attempted to analyze the students' errors using the following viewpoints: 1) interpretation of symbolic meaning, and 2) interpretation of specific meaning within the context. In order to get the needed data, 237 high school students and 248 college students were requested to answer problems on magnetic force. The following rules were used by students in analyzing their responses, to wit: (1) correct interpretation of force vector, (2) wrong interpretation of the symbolic meaning wherein the object behind the vector gives force to the object ahead of the vector, (3) wrong interpretation of the symbolic meaning wherein the object having the vector gives force to the object ahead of the vector, (4) wrong interpretation about the contextual meaning wherein the magnet possesses force that acts on another object. The students' answering patterns were constructed within the framework of these four rules. In theory, six answering patterns were defied by the four rules. It was found out that 89.9 percent of the high school students and 85.5 percent of the college students responded using these six answering patterns. Therefore the validity of these four rules seems to have been found.