An Practice Research On Current Teaching By The Concept Transformation Strategy

Electricity concepts are the important part of the electricity. A considerable amount of research has shown that there are many mistakes on the electricity concepts for middle school students. Those ideas will have a great effect on learning scientific conceptions.Studies have shown that not to study electrical and have learned electrical students are having many preconceptions by investigation, mainly contains:"The battery is a constant current source", "Consumption of current---- the electric current will be gradually consumed along the wire when it through the appliances", "Unipolar model --- it don’t need loop to produce electric current as long as the anode", "Current transmission takes time" and so on.Pass through the result, some electric preconceptions are easy to be changed by learning. For example, the Unipolar model and the Collision model. Some are hardly to be changed by traditional education. Conclude the five typical preconceptions. Contains:① Electric current will stop somewhere like water and it will have the electric current before the switch when it is been cut, after the switch is not.② Current transmission takes time, electric current will bigger near the cathode than away from it.③ Current through the bulb will be weaken in the series circuit, so electric current will bigger near the cathode than away from it.④ If the bulbs have the same size, current will be equal through them. If the bulb brighter, it will be divided more current. ⑤ Current will be affect by the distance of the wire, electric current will bigger near the mains than away from it.In order to change the preconceptions which it is considered hardly for students, the study apply matching transformation strategy in the instructional design. For example, the preconceptions that electric current will stop somewhere like water and it will have the electric current before the switch when it is been cut, we take the explore experimental strategy, triggering the conflict of students’ cognitive, And then change the preconceptions. Take the Visual teaching to change the preconception that current transmission takes time like water flowing and current through the bulb will weaken the existence of preconception, Use Flash can visualize the problem. In order to change the preconceptions about the series circuit, we can combine cooperative learning strategy with inquiry learning strategy.Considered that the major preconception ware being by mistake analogy to the "water model", put forward the" train model" and "bicycle model", students can build scientific electric current concept by analogy instead of original. So it can help students change electric preconceptions into the scientific concepts effectively and let students apply the new model to solve practical problems.At last, the author conducted an empirical study on the related preconceptions and changing problems in teaching electric current was found in middle school, carried out and the effect on the strategy of changing preconceptions was tested.By comparing the pretest and posttest showed very verify the effectiveness of the strategy changing electric current preconceptions, such as "Current transmission takes time", "the current on the cut the current", "Consumption of current", " The battery is a constant current source", "The resistance position influence the current". Proved that the strategy of changing preconceptions are effective.