‘‘Opportunities and Challenges for Sustainable Learning, Research and Community Service in Covid-19 Pandemic Constraints’
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A Case Study of K-8 Students’ Problem-Solving Skill on Pressure Subject
Matius Heru Wijayatno1*, Dadi Rusdiana2
1,2Magister of Physics Education, Indonesia University of Education, Bandung, Indonesia
*Corresponding Author: [email protected]
Abstract
This study aimed to get a general picture of K-8 students’ problem-solving skills on pressure subjects.
This study employed a qualitative method with a case study approach. Moreover, students’ problem- solving skills were measured based on stages of visualization/problem description, physical approach, particular physical application, mathematical procedure, and logical conclusion. The samples of this study were 30 K-8 students in a private school in Bandung. This study showed that students’ problem- solving skills at each stage were different. Nevertheless, the overall results were categorized into moderate.
Keywords: problem solving skill, skill, pressure
1. Introduction
Thinking skill is one of the skills that students must have along with the development of an increasingly sophisticated era. Those thinking skills are 1) creative and innovative thinking, 2) critical thinking and problem solving, and 3) learning how to learn and metacognition ability (Griffin and McGraw, 2012). The thinking skill referred to in this case study was problem- solving skills. Problem-solving skills are important to be trained for students from an early age as an asset to face future challenges. Physics is one of the subjects in which students can develop their problem-solving skills. In physics, problem-solving skill is a skill in using existing physical and mathematical concepts (Gustafsson et al, 2015). Pressure is a physics subject containing concepts that students need to understand so that they can apply the concepts and solve problems in their daily lives. Pressure concepts used in problem-solving of this study were pressure in solids, hydrostatic pressure, Pascal’s principle, and Archimedes’ principle.
Pressure is defined as force per unit area, in which the pressure works perpendicular to the surface (Giancoli, 2001).
Figure 1. Pressure in Solid
………... (1)
The pressure concept above is useful when discussing hydrostatic pressure. Hydrostatic pressure is pressure in liquids caused by the weight of the liquids itself. Hydrostatic pressure is directly proportional to the density of the liquid, gravitational force, and the depth of objects.
Mathematically, the relationship is written as follows:
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………. (2)
When a liquid-filled into a plastic with holes squeezed, the liquid will gush from every hole in the plastic. In this simple experiment, the water gushing out from a hole was just as strong as pressure given to every hole in the plastic. This phenomenon was first discovered by Blaise Pascal (1623-1662) who found that the pressure exerted on liquid in a closed container will be distributed with the same amount of pressure in every direction. This principle became the basis of hydraulic tools, such as hydraulic machinery. Hydraulic machinery is producing a large amount of lift on the big piston by only giving a small force on the small piston. In other words, hydraulic machinery is multiplying the input force.
Figure 2. Pascal’s principle
………. (3)
Another pressure concept is related to the phenomenon of objects' weight being lighter if they are lifted in the water than in the air. This phenomenon is caused by the upthrust force of liquid toward an object. The first person to investigate the upthrust force of liquid was Archimedes so that this is known as Archimedes’ principle which is “Any objects which are completely or partially submerged in a fluid at rest is acted upon by an upward force; the magnitude is equal to the weight of the fluid displaced by the object”. Another concept of Archimedes’ principle is that the volume of a submerged object in a fluid is equivalent to the volume of the displaced fluid. The amount of upthrust force experienced by a submerged object in a fluid can be calculated using the equation below:
………(4)
On a submerged object, two forces are working against each other which are the weight of the object (wb) and the upthrust force (FA). Therefore, Archimedes’ principle is closely related to the phenomenon of floating, suspending, or sinking. An object is floating if FA> wb, an object is suspended if FA = wb, and an object is sinking if FA < wb.
Figure 3. Buoyant force
‘‘Opportunities and Challenges for Sustainable Learning, Research and Community Service in Covid-19 Pandemic Constraints’
121 Facts in the field show that students still have difficulty in solving problems. Previous research supports that students' problem-solving skills are currently less satisfactory (Mustofa
& Rusdiana, 2016). Students’ cannot carry out qualitative analysis and find the appropriate concept to solve the problems (Zewdi, 2014).
This study aims to obtain an overview of the K-8 students' problem-solving skill in a private school in Bandung on the pressure subject. The stage of problem-solving skills used were visualization/problem description, physics approach, specific application of physics, mathematical procedure, and logical progression (Docktor and Heller, 2009).
2. Method
This study was conducted on 30 K-8 students in a public school in Bandung which had studied the pressure subject. This study employed a qualitative method using a case study approach. The data were collected using a problem-solving instrument consisting of four questions and must be completed in 60 minutes. The instrument used has been validated by experts and has a high-reliability category (0.80). The stage of problem-solving skill used were visualization/problem description, physics approach, specific application of physics, mathematical procedure, and logical progression with the distribution as follows:
Table 1. Subject distribution on each problem-solving skill indicator
Problem Solving Skill Indicators
Pressure in Solid
Hydrostatic Pressure
Pascal's Principle
Archimedes’
Principle Total Visualization/problem
description 1 1 1 1 4
Physics approach 1 1 1 1 4
Specific application of
physics 1 1 1 1 4
Mathematical procedure 1 1 1 1 4
Logical progression 1 1 1 1 4
Total 20
After students took the test, their answers were assessed using a rubric adapted from Docktor et al., (2006). After the problem-solving test results were obtained, the students were categorized based on the index shown the table below as suggested by Hidayat et al., (2017):
Table 2. Category of problem-solving skills Score (%) Category
0 – 30 low
31 - 70 moderate
71 - 100 high
3. Results and Discussion
Based on the data analysis of students’ answer in problem-solving skill test regarding pressure subject, the results are as follows:
‘‘Opportunities and Challenges for Sustainable Learning, Research and Community Service in Covid-19 Pandemic Constraints’
122 Table 3. Students distribution and the average score of problem-solving skill test
Score
(%) Category Total Average Category
0 - 30 low 3
69 moderate 31 - 70 moderate 10
71 - 100 high 17
Table 3 showed that K-8 students’ problem-solving skills in one of the public schools in Bandung were categorized as moderate. The average score of the 30 students who took the test was 69. Three students were categorized as low, 10 students were moderate, and 17 students were high. The highest score was 97 and the lowest was 14. Although it was categorized as moderate, students were having problems in physical approach and logical conclusion indicator.
It could be seen in Table 4 below which shows that students got the lowest average score on those indicators, namely 58 and 59.
Table 4. The average score of each problem-solving skill indicator
Indicator Score Category
Visualization/problem description 78 high
Physics approach 58 moderate
Specific application of physics 76 high
Mathematical procedure 72 high
Logical conclusion 59 moderate
In the visualization/problem description stage, the interpretation of a problem into a meaningful representation was done by summarizing important information in the form of symbols, visuals, and/or written forms. In this stage, most of the students were doing it correctly. A common mistake in this stage was the use of an inappropriate symbol to represent a unit. Figure 4 is an example of how to correctly answer the visualization/problem description stage.
Figure 4. A student’s answer in the visualization/problem description stage regarding pressure in solid
The physical approach stage was conducted by choosing an appropriate physical approach to be used to solve the problem. In this stage, students had a difficulty in conducting a qualitative analysis and finding the appropriate concept to solve the problem. Some students have left out this stage while others filled it with the equation which got the problem-solving done in the specific application of the physics stage. This mistake might be because they were not familiar with analyzing the question by finding the concept, so that they directly wrote the equation. This phenomenon was also discovered by Eunsook & Sung-Jae in Dheka et al., (2017) who found that students directly wrote mathematical equations and compared them to the problems in the examples. Figure 5 is an example of how to correctly answer the physics approach stage.
‘‘Opportunities and Challenges for Sustainable Learning, Research and Community Service in Covid-19 Pandemic Constraints’
123 Figure 5. A student’s answer in the physics approach stage regarding pressure in solid
In the specific application of the physics stage, students had to choose a more specific concept to be applied. For example, writing down the equations. In this stage, most students wrote the correct equations used in problem-solving. Some students’ mistake during this stage was that they tended to guess the equation used. Guessing and manipulating the equation cannot increase problem-solving skills (Docktor et al, 2015). Figure 6 is an example of how to correctly answer the specific application of physics stage.
Figure 6. A student’s answer in specific application of physics stage regarding pressure in solid This stage was a procedural stage to execute stage three by following the valid mathematical rules. Most students had carried out this stage correctly. This indicated that most students had good mathematical skills. A common mistake in this stage was that students did not convert the unit. The unit conversion was supposedly conducted in the visualization/problem description stage by following physical rules which are meter-kilogram- second (MKS) or centimeter-gram-second (CGS). Figure 7 is an example of how to correctly answer the mathematical procedure stage.
Figure 7. A student’s answer in the mathematical procedure stage regarding pressure in solid The logical conclusion stage was an overall evaluation and correction of whether the given solution was clear, concise, understandable, and consistent. A common mistake in this stage was that students only wrote the conclusion of their calculated results without conducting overall evaluation and correction. For example, students did not check the units and they did not understand the physics concept that they used. Figure 8 is an example of how to correctly answer the logical conclusion stage.
Figure 8. A studen’st answer in the logical conclusion stage regarding pressure in solid From the subject perspective, four students answered correctly on the pressure in solid, and five students answered correctly on hydrostatic pressure, and there were no students who answered correctly on all pressure subjects. Generally, students had difficulty with the Archimedes’ Principle with an average score of 58. Students still think that objects float due to the influence of hydrostatic pressure or buoyancy force without relating it to the weight of the material.
‘‘Opportunities and Challenges for Sustainable Learning, Research and Community Service in Covid-19 Pandemic Constraints’
124 Table 5. The average score of problem-solving skill on each subject
Subject Score Category
Pressure in Solid 72 high
Pascal’s Principle 67 moderate
Hydrostatic Pressure 77 high
Archimedes’ Principle 58 moderate
Figure 9. A student’s answer in Archimedes’ Principle subject
This result showed that learning conducted in class has not been able to make students master the whole concept of pressure. Consequently, they were having different concepts with experts’ concepts (Radovanonic & Slisko, 2013). By understanding the concept, students will be able to differentiate objects that they find in the surrounding environment (Thobroni &
Mustofa, 2013) and they can easily solve problems. Skilled students in solving problems are students who understand the basic concept of the problems (Lin et al, 2011).
4. Conclusion
Based on the results, K-8 students’ problem-solving skills on the subject of pressure in solid, hydrostatic pressure, Pascal's principle, and Archimedes’ principle were categorized as moderate (69) with a varied score in each problem-solving skill stage. Students’ lowest average score was on the physical approach stage (58), logical conclusion (59), mathematical procedure (72), particular physical approach (76), and the highest average score was in visualization/physical description (78). Whereas based on the subject, students had the lowest average score on Archimedes’ principle (58), Pascal’s principle (67), pressure in solid (72), and the highest was hydrostatic pressure (77). This study limitation is that it does not elaborate the problem-solving skills specifically per subject but only in a general way. The suggestion to the next researcher is to analyze problem-solving skills per subject so that it can detect students’
mistakes in learning the subject of pressure.
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