IETC - May 03-05 2007 Nicosia, T.R.N.C.
LORENTZ'S GLOVE
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TC
20 07
M. Sahin Bulbul Kafkas University, Turkey,
[email protected]
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IETC - May 03-05 2007 Nicosia, T.R.N.C.
ABSTRACT
20 07
This study tries to find advantages and disadvantages of using a glove, which is colored with blue, yellow and red, during the Lorentz's Force teaching. Generally teachers use right hand to show three dimensions for velocity, force, and magnetic fields. But students can not imagine or they have some difficulties to understand the Lorentz's law with simple (bared) right hand. The right hand method had been improved with colored glove method (CGM) called Lorentz's glove to solve imaging problem. One open ended question was used to determine student's view, whether they like physics lesson or not. Totally 40 students answered that she/he doesn't like physics, at Education Faculty of Kafkas University. They participated by answering the questions about Lorentz's Force after taking a course. These 40 students were divided to control and experimental group with equal qualities. After learning CGM and solving Lorentz's force questions there was an increase (%65) in member numbers enjoying physics in experimental group, however we didn’t notice any change in control group's opinion about physics. Keywords: Lorentz's Force, Physics Education
INTRODUCTION
Learning and teaching subjects in science as the magnetic field and magnetic force is very difficult both for teachers and students [1]. The reason is that in the real world there is no vector showing directions of fields and forces. Consequently some methods had been improved for teaching these subjects, which were called traditional methods ( TMs ) in this study. Alternative to TMs, we prepared a colored glove and tested by using as a method. Both the electric field and magnetic field can be defined from the Lorentz force, the law was showed at formula-1. The electric force is straight forward, being in the direction of the electric field if the charge q is positive, but the direction of the magnetic part of the force is given by the right hand rule [2]. Formula 1: Vectoral components of Lorentz's force.
Traditional Methods (TMs) for Lorentz Force Teaching
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While teaching Lorentz's force, except drawing and showing diagrams, teachers use right hand rule to solve problems and to learn the abstract subject of magnetic and electrical fields (figure-1).
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Figure 1: Showing force, field and motion vectors with right hand
Besides right hand rule some teachers choose the computer based way [3] by jawa applets showed in figure-2. You can reverse or close current and turn magnet to show dimension of vectors. There is a free wire system to move with Lorentz's force showed with black arrow.
Figure 2: Jawa applets for teaching Lorentz's force
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IETC - May 03-05 2007 Nicosia, T.R.N.C.
Using Colored Glove Method (CGM)
20 07
A glove painted with three different colors to show three dimensions is our basic material for CGM. It can be used both for negative and positive particle's movement. On yellow part there are positive and negative symbols (Figure3 and 4). When positive particles movement was investigated, we should turn our thumb, painted with blue, through particles moving direction and other fingers, painted with red, should be on same path with electromagnetic field. The way of positive symbol shows is the Lorentz's force direction. Same process is available for negative particles movement showed as negative symbol with opposite direction of positive particles. By wearing glove and turning blue finger to moving direction, namely current direction and turning red fingers to magnetic field direction, depending on particle's charge, you can find out the direction of Lorentz' s force.
Figure 3: A view from palm of the right hand glove.
Figure 4: A view from outside of right hand glove.
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Figure 5: Some applications with Lorentz's glove. Left side picture is for negative particle, right side picture is for positive particle
METHODOLOGY
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Two groups were composed including 20 students and there were totally 40 students. Each of them expressed that they don't like physics. Both groups took a course about Lorentz's Force. Control group learned with right hand rule but experimental group learned with CGM (Figure-5). All students were examined with ten questions about Lorentz's Force and their achievement percentage was exhibited in table-1. Testing student's opinion about physics, to determine whether they have been changed or not, an openended question was asked and the result was showed in table-2.
Table 1: Percentage of achievement at Lorentz's Force
Achievement at Lorentz's Force Test
Experimental Group
%80
Control Group
%45
Table 2: Percentage of Positive Opinion Changes about Positive Opinion Changes About Physics Experimental Group
%65
Control Group
No Changes
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IETC - May 03-05 2007 Nicosia, T.R.N.C.
20 07
RESULTS Answering five questions correctly from ten questions was accepted as achievement and table-1 was presented. Table-2 was prepared with answers from the “After this study is there any change in your opinion about physics?” question. CONCLUSION
Advantages and Disadvantages of Traditional Methods
Teaching with only computer based system supports learning, is not enough for adapting other questions and situations. There would be some problems and difficulties while imaging the simulation and adapting it to the question. Because computer based teaching isn't useful in everywhere and in all conditions, two methods should be used together. Although teaching Lorentz's force with computer based method and right hand method together is permanent way of learning, students should memorize finger's mean for field, motion and force. Advantages and Disadvantages of CGM
Concretizing vectors with CGM is easier than TMs. The reason is you can make connections between colors and vectors. It reclaims lesson from apprehensiveness and the lesson becomes enjoyable activity for students.
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CGM should be only used by teaching process. After teaching and practicing steps, there will be an availability problem. There is no colored glove production, so preparing it for each student will also bring some difficulties too. In this study we used only one glove and changed it during the lesson. Making own glove or changing it during the lesson is time wasting. Although CGM has an attribution that brought the achievement and involvement on physics, it isn't considered common and known method for physics teachers. REFERENCES
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Bayrak, B., Kanlı, U. and Kandıl Ingec, S., “To Compare the Effects of Computer Based Learning and the Laboratory Based Learning on Students’ Achievement Regarding Electric Circuits”, The Turkish Online Journal of Educational Technology - TOJET, ISSN: 1303-6521 Volume 6, Issue 1, Article 2, January 2007 Georgıa State Unıversıty, “Right Hand Rule”, http://hyperphysics.phy-str.gsu.edu/hbase/magnetic/ magfor.html#c3, 05.03.2007 Jeskova, Z., “Computer-aided experiment in physics teaching”, EUROCON 2003. Computer as a Tool. The IEEE Region 8, Volume: 2, On page(s): 335- 338 vol.2, ISBN: 0-7803-7763-X, 22-24 Sept. 2003
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