The Effectiveness of Demonstration-Based Chemistry

Study Case The Effectiveness of Demonstration-Based Chemistry Learning in Improving Mastery of Colloid System Concepts Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract The application of demonstration methods in chemistry teaching is considered an effective strategy for improving student academic achievement, as this method is able to transform abstract concepts into concrete phenomena in the classroom. This study was conducted on vocational school students at Cincinnati Vocational High School during the 2013 academic year. The learning process was carried out in three cycles on the topic of colloid systems. The class was divided into two groups: an experimental class and a control class. The experimental class was taught using the demonstration method, while the control class used the conventional lecture method. Evaluation was conducted through multiple-choice tests before and after the learning process. The results showed that the demonstration method significantly improved students' chemistry learning achievement. Students in the experimental class taught using the demonstration method had an average score (M = 19.08 ± 0.74), which was higher than that of the control class (M = 12.91 ± 2.52), with a statistically significant difference (t_count = 22.85 > t_table = 1.66). The effectiveness of the demonstration method in the experimental class reached 97%, higher than the conventional method in the control class of 91%. Keywords: effectiveness, demonstration method, learning achievement, colloid system, vocational school. INTRODUCTION The application of appropriate learning methods is an important strategy for improving student learning outcomes. Appropriate methods can help students understand abstract concepts in a more tangible and practical way. One approach that MICHAEL KURNIAWAN 1 Study Case has proven effective in chemistry learning is the demonstration method, which can strengthen students' mastery of colloidal system material at the vocational high school level. According to previous research , chemistry learning becomes more interesting when delivered through varied and interactive methods. Presenting material through demonstrations allows students to observe real phenomena directly in the classroom, so that chemistry concepts are not only understood theoretically but also visually and practically . The demonstration method is classified as a classic method but remains relevant in the context of modern chemistry learning. This method involves demonstrating objects, processes, or scientific principles directly in front of students, using tools, materials, and supporting visual media. To successfully implement the demonstration method, there are several steps that teachers need to pay attention to, including: a. clearly defining the objectives of the demonstration so that learning outcomes can be measured; b. thoroughly preparing the theory, materials, and equipment; c. managing the demonstration time efficiently; and d. creating a conducive classroom atmosphere so that students are motivated to pay attention . The technical steps for implementing the demonstration method are described by Saragih and Situmorang , including: (1) preparing tools and materials in a position that is easy to observe; (2) arranging the seating position of students so that all can see clearly; (3) ensuring that the teacher's position does not block the students' view; (4) maintaining the students' focus during the demonstration; (5) repeating important parts; (6) asking oral questions to gauge understanding; and (7) asking students to explain the process they have observed. The demonstration method has various advantages, such as increasing students' focus on important matters, reducing conceptual errors, and providing meaningful direct learning experiences. Students' active involvement in the demonstration process can also improve their psychomotor skills and social understanding of scientific processes. In addition, demonstrations help answer students' conceptual questions directly through empirical observation . However, this method also has several limitations, such as difficulties in implementation when there are too many students, time constraints, and technical obstacles when tools or materials cannot be clearly observed. This method also risks MICHAEL KURNIAWAN 2 Study Case becoming merely a passive spectacle if students are not directly involved in the practice. Psychopedagogically, the demonstration method provides significant benefits because it is able to focus students' attention, direct the learning process to be more focused on the material, and create a strong impression on the learning experience. Demonstrations can also correct errors that arise in traditional lecture methods by presenting real objects or concrete visual simulations. The Context of Chemistry Curricula in Vocational Schools in the United States In the context of vocational education in the United States, chemistry learning curricula are developed based on the National Science Education Standards set by the U.S. Department of Education and implemented in various institutions such as the University of Cincinnati Technical Preparatory Programs. This curriculum emphasizes a balance between cognitive, affective, and psychomotor development, as well as the application of hands-on learning. The structure of the vocational curriculum includes three main components: a. General Technical Foundation, which covers the basics of science and technology; b. Applied Science Skills, which focuses on the application of scientific concepts in the industrial world; and c. Specialized Professional Modules, which are aimed at mastering specific skills according to the students' career fields. Chemistry is included in the Applied Science Skills group, which aims to enable students to apply scientific principles to industrial, health, agricultural, and engineering technology activities. One of the main topics in this curriculum is Colloidal Systems, which covers the ability to design, create, and analyze various colloidal systems using materials found in the environment, as well as understanding their physical and chemical properties. RESEARCH METHODS This research is classroom action research that follows procedures adapted from Situmorang . The research was conducted at Cincinnati Vocational High School, Ohio, during the 2013 academic year. The research population consisted of three parallel classes at the vocational school level, namely two classes in the Plant Production Technology (PPT) department with a total of 71 students, and one class in the MICHAEL KURNIAWAN 3 Study Case Mechanical Automotive Engineering (MAE) department with 42 students. Samples were selected using purposive sampling based on previous research guidelines . From the three classes, first-year students were selected and divided into two groups: an experimental class and a control class. Each class consisted of two subgroups: a High-Performance Group (HPG) and a Low-Performance Group (LPG), based on previous academic scores (equivalent to junior high school national exam scores). From each class, 12 students were selected as research samples. The research instruments included two learning approaches, namely the demonstration method for the experimental group and the lecture method for the control group. Data collection was carried out through a multiple-choice test covering three stages of evaluation, namely: 1. Initial evaluation (pretest) — to determine the students' initial abilities. 2. Final evaluation I (posttest 1) — conducted after the application of the first learning method. 3. Final evaluation II (posttest 2) — conducted one month after the completion of learning to measure learning retention. The evaluation questions were developed by the researcher based on curriculum guidelines and content validity that had been tested through preliminary trials. The level of difficulty of the questions was standardized to be balanced between the control and experimental classes. Figure 1. Procedure for implementing actions in classroom action research on the effectiveness of the demonstration method in teaching colloid systems in cycles 1 to 3. MICHAEL KURNIAWAN 4 Study Case The research procedure consisted of three main stages: instrument preparation, learning implementation, and learning outcome evaluation. The experimental class was taught using the demonstration method, while the control class was taught using the conventional lecture method. To maintain internal validity, several variables were controlled, including: 1. Both classes received the same teaching material, namely the topic of Colloidal Systems with the subtopic Components and Classification of Colloids. 2. The duration of learning for both classes was made identical. 3. The same teacher was used for both methods to minimize instructional bias. This classroom action research was conducted in three cycles consisting of: 1. Cycle I: Learning about suspension dispersion systems. 2. Cycle II: Learning about solution dispersion systems. 3. Cycle III: Learning about colloid dispersion systems. Each cycle consisted of four main stages: 1. Planning — included the design of learning tools for demonstration and lecture methods, the preparation of test instruments, and the grouping of students based on their initial abilities (high and low). 2. Action — implementation of teaching and learning activities according to the design, where the experimental group uses interactive demonstrations and the control group uses lectures. 3. Observation — conducted to monitor student engagement, classroom dynamics, and the effectiveness of the implementation of learning methods. 4. Reflection — includes analysis of learning outcomes, observation of student behavior, and improvement of teaching strategies for the next cycle. The output of each cycle is quantitative data on student learning achievement, which is measured by comparing pretest, posttest 1, and posttest 2 scores. These results are used to determine significant improvements between the experimental and control groups and to measure the effectiveness of the demonstration method on student concept retention. RESEARCH RESULTS AND DISCUSSION This classroom action research was conducted on the teaching of colloid systems in vocational school chemistry classes. In the experimental class, learning was conducted MICHAEL KURNIAWAN 5 Study Case using a chemistry demonstration package developed by the researcher. Meanwhile, the control class received instruction using the traditional lecture method. Both groups received the same material, duration, and teacher; the only difference was in the instructional strategy used. In the experimental class, the demonstration method was used as a supplementary tool to theoretical explanations, while the control class only received verbal explanations with reinforcement on conceptual aspects without practical activities. To ensure sample homogeneity, a pretest was conducted on all participants before learning began. Students with extreme initial scores (too high or too low) were categorized as outlier samples and excluded from statistical calculations, although they still participated in the learning process. In general, the pretest results showed that most students did not yet understand the colloid system material, with low average scores in the range of 3–10 correct answers out of 20 questions. The average score for the experimental group was M = 4.33 ± 1.22 and for the control group M = 4.08 ± 1.42. Statistical analysis showed no significant difference between the two (t_calculated = 1.32 < t_table = 1.66), which means that both groups had equivalent initial ability levels. Table 1. Students' initial mastery of colloid systems based on evaluation results before learning. Note: HPG = High-Performance Group (high-achieving students); LPG = LowPerformance Group (low-achieving students). Further analysis was conducted to distinguish the initial abilities of high- and low- MICHAEL KURNIAWAN 6 Study Case achieving students. In the high group, the pretest results showed low abilities in both the experimental (M = 4.29 ± 1.32) and control (M = 4.13 ± 1.42) classes, and there was no significant difference (t_calculated = 1.24 < t_table = 1.67). Similar results were obtained for the low group, with the experimental (M = 4.36 ± 1.17) and control (M = 4.02 ± 1.44) values also not significantly different (t_calculated = 1.21 < t_table = 1.67). These findings indicate that the student population is homogeneous and suitable for further treatment. Furthermore, after implementing learning for three cycles on three subtopics— suspension systems, solution systems, and colloidal systems—a final evaluation (posttest 1) was conducted. The results are summarized in Table 2. Table 2. Student learning outcomes based on the final evaluation of colloidal system teaching (Posttest 1). Note: HPG = high-achieving student group; LPG = low-achieving student group. The results show a significant improvement in the experimental class (M = 19.08 ± 0.74) compared to the control class (M = 12.91 ± 2.52), with a statistically significant difference (t_calculated = 22.85 > t_table = 1.66). These findings are consistent with previous studies , which state that the use of the demonstration method can improve conceptual understanding of chemistry. When analyzed based on achievement level, high-achieving students in the experimental class obtained a score of M = 19.20 ± 0.73, while the control class only obtained M = 13.29 ± 1.70 (t_calculated = 21.88 > t_table = 1.67). Meanwhile, lowachieving students also showed significant improvement: the experimental group scored M = 18.96 ± 0.74 and the control group scored M = 12.53 ± 3.12 (t_calculated = 13.68 > t_table = 1.67). Analysis of each cycle shows a consistent pattern of improvement: • Cycle 1 (Suspension Systems): The experimental class (M = 19.43 ± 0.68) was higher than the control (M = 14.60 ± 0.93), t_calculated = 22.97 > t_table = 3.57. MICHAEL KURNIAWAN 7 Study Case • Cycle 2 (Solution Systems): The experiment (M = 18.90 ± 0.71) was higher than the control (M = 13.33 ± 1.32), t_calculated = 20.35 > t_table = 3.57. • Cycle 3 (Colloidal Systems): The experiment (M = 18.90 ± 2.86) was higher than the control (M = 10.80 ± 3.03), t_calculated = 14.26 > t_table = 3.57. These findings indicate that the application of the demonstration method has a significant positive effect on student learning outcomes in all chemistry subtopics taught. To measure long-term retention, a posttest 2 was conducted one month after the learning ended. The results showed that the experimental class retained higher learning outcomes (M = 18.44 ± 0.69) than the control class (M = 11.77 ± 2.48), with a significant difference (t_calculated = 26.68 > t_table = 1.66). These results indicate that learning using the demonstration method not only improves immediate achievement but also strengthens memory retention of the chemistry concepts taught. The effectiveness of learning was measured by comparing the average posttest 2 scores to posttest 1 scores, as summarized in Table 3. Table 3. Effectiveness of learning methods in improving student learning outcomes in teaching colloid systems (average of three cycles). The data in Table 3 shows that the effectiveness of the demonstration method (97%) is higher than that of the lecture method (91%), both for high- and low-achieving students. This confirms that the demonstration method provides a concrete learning experience that helps students understand and remember colloid system concepts more deeply. The slight decline between posttest 1 and posttest 2 is likely due to the habit of some students to learn by memorizing without understanding the concepts. However, this decline is relatively small in the experimental group because the active involvement of students during the demonstration process helps strengthen their mental representation of the concepts being learned. MICHAEL KURNIAWAN 8 Study Case CONCLUSION The results of this study indicate that the demonstration method is an effective learning strategy for improving chemistry learning outcomes, particularly on the topic of colloid systems, at the vocational school level. Students who learn through demonstrations can directly observe chemical processes, making abstract concepts easier to understand and remember in the long term. The demonstration method proved to be superior to the lecture method, as shown by the increase in learning outcomes and learning effectiveness: the experimental group achieved an average effectiveness of 96–97%, while the control group only achieved around 91%. This effectiveness applies to both high and low ability students. REFERENCE MICHAEL KURNIAWAN 9 Study Case MICHAEL KURNIAWAN 10