| With the development of the carry-out of science inquiry-oriental teaching & learning, teachers and students feel that there are many difficulties during science inquiry-oriented teaching & learning. such as in the part of designing experiments which include several dependent factors. It is very hard for students to ensure and control more than one variable. but in junior high school classroom, some teachers often prefer to train the students design experiment, ignored to allow students experience the full exploration process. They believe that it enabled students to understand control variables quickly and students can save a great deal of time to practice. But with the deepening spread of this started teaching methods, teachers felt that many students can not accept "all other factors remain unchanged" strategy quickly, and they even feel hard to correct them. Therefore, the study of teaching methods which can enhance students'level of migration about controlling variables, can improve students′ability of Scientific Exploration and teachers′teaching practice and improve the teaching of science very well.based on the basis of Piaget′s cognitive structure,Ausubel meaningful learning theory and so on, this research applies microscopic inspection to review the two modes of teaching: train the students design experiment and allow students experience the full exploration process so as to observe their impacts on students′understanding of the concept of controlling variablesThe results show that: after receiving the first kind of instruction, control classes′achievement on the first and third problem have been significantly enhanced respectively, however there are not significant improvement on the second problem. After receiving the second kind of instruction, experimental classes′achievement on all the three problems were all significantly increased. Generally speaking, experimental classes′results were much higher than control classes′especially in the face of subjects about experimental data explore, which are relatively profound to the students. When they are confronted by such subjects, control classes′results are not significantly improved while experimental classes′results have been significantly improved. the result indicates that: second kind of instruction can better promote the migration ability to control variables in different situations.during the carry-out of second instruction , students who were difficult to understand the control variable can be divided into three states: 1﹑ intuitive state: in the face of unfamiliar situations or concepts, students will directly draw a conclusion or design an experiment without contrastive experiment; 2﹑entire imitational state: student like to copy the previous test model or copy other people′s experimental method completely so that they know how to control variables from the surface , either by refrence to teachers′willing; 3﹑ variable-disordered state: The test showed that some students in the disordered state do not know which variables would be changed and which variables should remain unchanged.By teaching (as shown below), aliquot students in intuitive state will step into the phase of variable disordered state, then comes into the control variable, which is the most difficult stage .with the help of teachers or students, Some students can complete the experiment, but when they encountered a strange problem scenarios, they will return to the foregoing stage of entirely imitational state. We believe that allow students experience the full exploration process can help students to understand the nature and purpose of controlling variables. This teaching methods can also allow teachers to understand individual differences about studying control variables and allow teachers to see these types of subjectsˊ law in their thinking process of development of understanding the course of controlling variables.finally, the thesis give a summarization from the pros and cons of the test and lack of the teaching methods. |
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