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Asia-Pacific Forum on Science Learning and Teaching, Volume 18, Issue 2, Article 1 (Dec., 2017) |
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Asia-Pacific Forum on Science Learning and Teaching, Volume 18, Issue 2, Article 1 (Dec., 2017) |
Students’ development of understanding about photoelectric effect
The PECE revealed some common misconceptions of photoelectric effect held by the participating students as Table I.
Table I. Students’ common misconception of photoelectric effect expressed from PECE
Components of PECE
Common misconception
Correct conception
a) Electromagnetic (EM) model of light
Students use the photon model of light.
Students use the electromagnetic model of light.
b) Photon model of light
Students use the electromagnetic model of light.
Students use the photon model of light.
c) Characteristic of photon
The energy of the red light photon is greater than the energy of the yellow one.
The energy of the red light photon is less than the energy of the yellow one. (Energy of photon depend on frequency rather than intensity).
d) Threshold frequency
Students cannot relate conception of frequency light associated with emission of elections.
All the lights which has frequency greater than yellow light will emit electrons when shone to that particular metal.
e) Work function
Student cannot relate the conception of work function with energy of photon which in turn depends on frequency of light.
Potassium and sodium will be able to emit photoelectrons since the energy of ultraviolet is greater than the work functions of those metals.
f) Maximum kinetic energy
Student cannot relate the conception of work function with energy of photon which in turn determines the maximum kinetic energy of emitted electrons.
Potassium will be able to emit electrons since its work function is less than the energy of the light.
g) Stopping potential
Student do not have conception of stopping potential, which depends on work function of the metal.
Rank of the stopping potential from largest to smallest: Potassium > Sodium > Aluminum > Tungsten > Copper > Iron > Gold > Platinum.
In addition, the students’ post-test scores were higher than pre-test scores in all constructs of PECE. The students gained more understanding specifically to the Threshold Frequency and the Work Function constructs.
Figure V. Students’ score in each construct of PECE
This finding showed that the photoelectric effect simulation and game helped concretize the abstract concepts of photoelectric effect, which otherwise would be difficult for the students to visualize. The students’ highest post-test score was on the concept of photon model of light, which could be attributed to power of simulation created in this study in helping the students visualize the photon model of light. In overall, the students’ post-test scores were higher than 50% except for the concept of EM model of light, which the students gained the lowest post-test score. This is because the photoelectric effect learning unit created in this study was not dealt comprehensively with the concept of EM model of light; the EM model of light was raised as one example to contradict the photon model of light. The mean of students’ pre-test score was 12.94 (SD = 3.81) and the mean of post-test score was increased to 16.94 (SD = 3.12). The normalized gain analysis (Hake, 1998) revealed that the overall normalized gain score for the participating students was .352. In addition, the paired sampled t-test reveals that after attended the simulation and game based instruction on photoelectric effect the participating students significantly improved their understanding about photoelectric effect (t (30) = 7.79, p < .05). The paired sample correlations showed that the pre-test and post-test scores were statistically correlated (r = .671) at the .01 significant level.
Table II. Paired sample t-test of pre- and post-test of PECE
Mean
Std. Deviation
Std. Error Mean
t
df
p-value
Post-test – Pre-test
4.032/p>
2.881
.517
7.793
30
.000**
** The statistically significant difference level at .01
In addition, the estimated Cohen’ d was 1.40, which implied that the simulation and game based instruction improved the mean scores by 1.40 of the sample SD. Cohen (1988) suggested the criteria for evaluating a size of treatment effect and a magnitude of 1.40 was considered as a large effect size.
McKagan et al. (2009) used simulation to teach photoelectric effect but they did not mention about the teaching and learning approach used. This study shows the effectiveness of the simulation and game embedded in the 5E learning cycle in teaching the photoelectric effect concept. The simulation and game requires the students themselves to discover different aspects of the photoelectric effect phenomenon. The students can take advantage of the Exploration phase in the 5E learning cycle in generating various hypotheses to explain the photoelectric effect phenomenon and then testing those hypotheses (Blank, 2000). The simulation and game help the students to be able to deduce the relationship between the frequency of light and the emission of photoelectron as well as the relationship between the intensity of light and the number of emitted electron. The most important concept learned by the students is that the emission of photoelectrons depends definitely on the frequency of light irrespective of its intensity. Almost all students could predict the result of photoelectric effect phenomenon when altered various factors in the photoelectric effect simulation. The students could correctly state that the frequency of light must be above the threshold frequency to let the photoelectron emission to take place. Also, the threshold frequency is unique for a specific type of metal. The frequency of light is directly proportional to the energy of photon, which is considered as packets of energy. The students can accommodate the concepts of photoelectric effect phenomenon and use many evidences to build the photon model of light. The students could find stopping potential, which measures the maximum kinetic energy and used this data along with the frequency of light to plot the related graphs. These graphs give Einstein’s photoelectric equation and the students knew the meaning of the equation, which otherwise would be presented directly to them in their regular physics class. The most important information from the graph is the slope of the graph, whose value is equal to the Planks constant. It means that energy of light is quantized and its magnitude can be an integral multiple of Plank’s constant. The students were able to relate how light exist as packets of energy and what happens when the frequency of light is increased. While interacting with the simulation and game, the students take control of their learning and actively constructed knowledge by themselves. This is necessary for students’ conceptual development and aligned with the constructivist philosophy (Duit & Treagust, 1998).
Students’ attitudes toward the simulation and game based instruction in photoelectric effect
The analysis showed that the students gained not only understanding about photoelectric effect, but also positive attitudes to the simulation and game based instruction. In overall, the participating students had positive attitudes towards the simulation and game based instruction to teach photoelectric effect (mean = 4.43, SD = .72).
Table III. Students’ attitudes towards the simulation and game based instruction on photoelectric effect
Dimension
Mean
SD
1. Students’ views toward computer interaction
4.45
.72
2. Students’ degree of involvement in the multimedia activity
3.70
.96
3. Students’ views on individualize instruction
3.71
.81
4. Students’ perceptions toward self-paced instruction
4.12
.84
5. Students’ perceptions of application’s user friendliness
4.23
.77
6. Students’ level of anxiety when working with multimedia
4.11
.93
Total
4.43
.72
From MAS, the students had the highest and lowest attitudes towards the simulation and game based instruction regarding its interaction and degree of involvement with multimedia, respectively.
After finished the photoelectric effect class, the participating students were asked to write their reflective journals. The thematic analysis revealed five themes emerged as being shown in Table 7. Most of the students (n = 26) reflected that the simulation and game based instruction helped them understand the concept of photoelectric emission. In addition, more than a half of the students reflected that the simulation and game based instruction was enjoyable and attentive.
Table IV. Summary of students’ reflections from reflective journal
Theme
Statement
Frequency
Photoelectric emission
Emission of photoelectron does not depend on intensity of light but on frequency of light.
26
Being enjoyable and attentive
Simulation and game was fun to explore and drew my attention
17
Threshold frequency
Light should have minimum threshold frequency for the emission
16
Visualization and Understanding
Students could visualize the concept and had better understanding
10
Student Centered
Students could explore by themselves
4
After completion of the whole learning unit, six students were randomly selected for interview to provide further evidence for supporting the results from PECE, MAS, and reflective journal. The students’ comments on the photoelectric effect learning unit were:
Table V. Summary of students’ reflections from interview
Topic
Summary of students’ reflection
Photoelectric effect class
The lesson was well designed unlike our regular class where theories were directly described from the test. Students could observe and do the experiments therefore learning was easier and spontaneous without any rote learning.
Photoelectric effect phenomenon
Students could correctly describe the photoelectric phenomena and predict the result when various factors affecting the phenomena were altered.
Photon model of light
Students could describe the photon model of light using the result from the photoelectric phenomena but description of some relation was not that vivid.
Simulation and game
Simulation and game were interesting and fun to explore, and they could learn many new things related to photoelectric phenomena without much guidance from the teacher.
Photoelectric effect class
Some students said that the photoelectric effect lesson was not monotonous like their regular physics classes where they had to learn the theoretical concepts from the textbooks and did not have much room for visualizing the concepts. In this class, they could visualize the photoelectric effect concept and could explore by themselves with little guidance from the teacher.
We enjoyed a lot; it was not monotonous as a regular class we used to have. In our regular class, we use to have black and white image from the text, we were unable to visualize the exact concept. We were unable to conceptualize what is being taught. From the simulation and game we were able to perform by ourselves without the aid of our teachers, we were able to perform just simply by reading the questions (Student 21).
While learning from the text book, we have to go line by line, each and every detail had to be referred but in case of simulation, as soon as we see the question, we can perform in the simulation. In simulation we need not go line by line or read every detail of that because whatever question is asked, we are able to visualize in front of us, we can easily comprehend what is there (Student 27).
Photoelectric phenomena
Students could correctly state the factors affecting the photoelectric phenomena and predict the results that accompanied when various factor were varied. They were able to state that emission of electron is directly proportional to the frequency of light but independent of the intensity of light. The number of photoelectrons emitted depends on the intensity and the kinetic energy of the emitted electron depends on the frequency.
With the help of simulation we can see with our eyes and we knew that intensity does not play role for the emission whereas frequency is more important, since frequency is required to overcome the work function of the metal in order to emit the electron from the surface of the metal. The frequency of a light should be more than the threshold frequency of the metal for the emission to take place, if it is less then no matter how much is the intensity, electrons will not be emitted. The emission of photoelectron depends on frequency but is independent of intensity of light (Student 05).
I learned the energy of electrons emitted is related to frequency. How the wavelength and frequency differ, and how it relates to emission of electrons. Intensity is directly proportional to number of electrons emitted from the surface of the metal. In case of frequency, if the frequency is higher, energy of electron emitted will be higher. Frequency is the factor which is the key for the emission of electron from the surface. For the emission, frequency is required but number of electrons emitted will depend on intensity of light (Student 09).
Photon model of light
The students were able to state that the in photoelectric phenomena, the transfer of energy between light and electron take place between packets of light energy and the electron. Therefore, there is instantaneous emission at very low temperature.
We know that diffraction and refraction can be explained by wave nature but due to particle nature, there is an emission of electron in photoelectric effect. This emission of electron will not be possible if there is no transfer of energy from particle to particle. The electrons ejected are at low temperature which shows that energy is transferred from particle to particle (Student 05).
When we expose the metal to the light with certain frequency and intensity, it is knocking the electron from the orbital, so in order to knock something, something has to have momentum and that momentum is the property of particle nature. That is why I came to know it is a particle nature (Student 02).
Simulation and game
The students were satisfied with learning outcome using simulation and game. They stated that simulation could bring theory to reality where they observe and learn. Also, game was fun to play and at the same time there was learning.
It is a new idea, before it used to be just only text book, and learning was theoretical one. But this simulation helps to bring theory into reality and we can see and observe experiment. Students used to learn directly from the text and students did not have opportunity to deal with this kind of experimental simulation. I knew the theoretical aspect of photoelectric effect from my regular class, but I did not know how it works in reality? How emissions of electron take place from the metal surface? How frequency and intensity of light affects the emission of electron. Before, I by hearted the phenomena and the factors affecting it. After doing a simulation in the class, I found that learning was easier and spontaneous without having to by heart (Student 01).
MAS shows that students are satisfied with the simulation and game instruction to teach the photoelectric effect concept. Most of the students reflects that the simulation and game based instruction is student-centered and they can learn with little guidance from the teacher. The students are enjoy and able to comprehend the photoelectric effect concept through visualization. The students like the interface of the simulation and game since they can carry out the activities with ease. They interact with the simulation and game by simply following the direction given. This is why the attitude mean score of the Interaction scale is highest. However, the students had low attitude mean scores on the Involvement and the Individualize Interaction scales. This might be because of the rules and knowledge required by the students for playing game. The students commented that it was interesting only after knowing certain rules and how to solve the problems. The students interact with the photoelectric effect simulation individually and they reflected that it would be better if they could perform in pair. The attitude mean scores for the Self-paced Instruction, User Friendly and Individual Anxiety scales were 4.12 (S.D. = .84), 4.23 (S.D. = .77), and 4.11 (S.D. = .93), respectively. It implies that students like the simulation and game, and they are comfortable to the learning unit. The photoelectric effect game was used in the Evaluation phase since it has an attribute of self-motivation and reward. In addition, the simulation and game activities were designed to fit into the constructivist philosophy (Amory, Naicker, Vincent, & Adams, 1999; Klassen & Willoughby, 2003).
Copyright (C) 2017 EdUHK APFSLT. Volume 18, Issue 2, Article 1 (Dec., 2017). All Rights Reserved.
