Research On The Primary Schoolchildren's Understanding Of The Phenomenon Of Expanding Of Substance With Heat And Contracting With Cold

With the deepening of Chinese education reform, people tend to pay more attention to the education of elementary science .So it is essential we prove into the teaching and learning of difficult points in the science curriculum. Studies of this kind may greatly improve our teaching of elementary science. From interviews with students and watching teaching kinescope, we find that our pupils have difficulty in understanding the phenomena of expanding of substance with heat and contracting with cold. A number of preconditions are required for pupils to acquire such knowledge. These include: the ability to differentiate the states of solid, liquid and gas, and when heated or cooled, liquid in the pipe ascending or descending, the knowledge of students that its mass keeps in the same. This thesis studies the of preconditions of pupils studying the phenomena of expanding of substance with heat and contracting with cold, and by using the method of Piaget' interviewing, interviews some students from a certain middle school and a primary school, and gains the following findings:1． Most children aging from four to five are able to distinguish the solid from the liquid, and they know that water flows, and its shape changes, but it is not the case with a stone. 2． Students learn the diffusibility of air by themselves (About by the ages of junior high school).3． Most students in the sixth grade (11-12 years old) know that the mass of liquid in the thermometer keeps in the same when the liquid is heated and rises. Primary school students will meet a lot of difficulties when they study the content4． of expanding of substance with heat and contracting with cold. And the difficulty is that most students in fourth grade or fifth grade will think that the quantity of liquid increase as the surface of liquid rise in the glass pipe. (Students cannot differentiate the concept of mass from the concept of volume). Most students in the sixth grade can know that the mass of the liquid in the thermometer keeps the same, but they tend to think that the volume of the liquid also keeps the same. When heated, liquid rising in the pipe, and there must be some space in the vacuole, which is not occupied by the liquid. It is very difficult for primary school students to think as same as we can that mass keeps the same, but volume keeps expanding. 5． There is a very positive correlation between the task of conservation of external volume and the task of the mass of liquid keeping in the same in the thermometer, as it is heated.6． The task of conservation of external volume is more difficult for primary school students than the task that liquid in the thermometer keeps the same. It isn't because of students lacking the ability of differentiating the concept of mass from the concept of volume that makes them unable to find out that liquid rises but keeps the same, it may relate to the development of students' logic.