A Preliminary Study On College Students' Comprehension Of The Conceptual Of Electrostatics

The concept of Physics is the most important and basic content in the physical foundation knowledge. In the physical teaching, the core problem of physical teaching is making the students become clear physical concept, grapping physical regulation accurately, and making their intelligence and ability get a full development. Since 1970s, student's comprehension to physical concepts and research on concept change has been a hot spot in international physical education research.The electrostatics is an importance part in electromagnetism. The research on concept of electrostatics is less in the domestic, but some students exist a lot of misconceptions for this part. This paper is to probe the misconceptions that students exits through a questionnaire combining with clinical interviews. According to study, more misconceptions are found on the comprehension of some electrostatics concepts. And the students'comprehensions still stay the level of round a high school. Misconceptions are existed as follows:1. Concept of electrification by rubbing. (1) Think the reason of charging by rubbing is the different ability fetters of an atomic nucleus to electronic and the transfer of charges between rubbers is two-way. (2) When rubbing the transfer of electronics is considered as one-way, not bilateral-way; (3) The key factors of electronic transfer is the heat when rubbing; (4) Rubbing produces heat so as to make electric charge separated. Positive charge moves toward friction, electronics move to another way; (5) When rubbing metals conductor, the tie ability of the atom to electronics is so strong that electronic cannot transfer, so they are not electrified.2. The electric charges distributes on the insulator/conductor. (1) Electric charge distributes part getting in touch with in insulator, but scatters homogeneously on the conductor. (2)The electric charges can distribute evenly on the insulator. (3) The same isolated conductor, the electric charges can scatter on both ends and one end is negative charge for positive charge another one end.3. The electrostatic induction of conductor. (1) According to the direction of electric field lines to judge the electric potential height, then judges electronic flow direction again according to electric potential height. (2) Conductor A is considered as an isolated, and the misconception is used as"difference of charge". The main performance is: when the left of conductor A is touched, the electronics will transfer to ground because the left carries much more electronics. And when the right is touched, the positive charges will be taken, or be neutralized by the electronics because the right carries much more positive charges. (3) The concept of equipotential body is not clear. The electric potential difference is existed on both sides when static equilibrium. The transfer of charges is judged by attraction or reject (Coulomb's Law). (4) Understanding of static equilibrium. The static equilibrium is come when the quantity of generating charge and generated charge is equaled.4. Polarization of dielectric. (1) Use concept of polarization correctly, make the accurate judgement and analysis to physics phenomenon. (2) Employ the explanation of electrostatic induction,and these students compare the electrostatic induction phenomenon of conductors, can also do an accurate judgment and relatively reasonable of two experiments. And the explanation of"induced charges"are similar with polarization of dielectric. (3) Employ the explanation of electrostatic induction principle, but they don't know "induced charges" are come from, they will have the usage of choice this principle when different material is presented. (4) Think the round of charges exist force just as two objects are existed universal gravitation. They think there will be a force when charges are laid and the more charges the more strength force will be. These students are not clear to force principle of electric field, and consider all things are endured force in an electric field.We find that students'comprehension the conceptions of electrostatic exist four levels through analyzing deeply: 1. Electrical potential, electric field lines level (few students). At this level, students have a good understanding of electrical potential and electric field lines, they also understand clearly about the reasons and processions of electrostatic charge's transfer. 2. Coulomb's force level (more students). At this level students do not understand concepts of electrical potential and electric field lines clearly, do not know what the using of electrical potential and can not judge the higher or lower of electrical potential. 3. Electric fluid level (more students). Students think charges could flow in dielectrics or conductors like liquid at this level. 4. Universal gravitation model level (few students). At this level students think bodies of charged could attract wisps like two objects exist universal gravitation and the more charges the more strength of force. These students do not understand force principle in electric fields clearly, and think all things in an electric field would endure the force.For students'comprehension of the conceptions not forming system, they have conflict ideas to one concept themselves. At different physical presentation we find that students will at different levels.Finally, combined with study theory of construction, some reason of false concept is analyzed, and some teaching suggestion is put forward.