Lorentz Force Experiment Prop based on IoT (E-Lorentz) to Support the Learning Process of Physics Subject for 9 th Grade

− Lorentz force teaching aids are proven to improve student’s cognitive abilities. The average result of N-Gain after using Lorentz force prop is 0.8 which is included in the high category. In the learning process, the teacher needed to design the course content, guiding, directing, and evaluating student learning outcomes. In the current situation, this learning process is still being done conventionally. Along with the development of technology, the Internet of Things (IoT) can facilitate the teaching and learning process. IoT allows data to be sent across a network without the need for human-to-human or human-to-computer interaction. The implementation of IoT in Education can also be called Internet of Education Things (IoET). IoT has many benefits in the teaching and learning process for both teachers and students. Students can learn directly with teaching aids so that their cognitive understanding increases. Teachers can also curtail activities that were previously done manually by reading activities that have been automatically saved, such as preparing, directing, giving questions, to recapitulating assessments. In this study, IoT technology has been implemented into the Lorentz force teaching aid (E-Lorentz) and the system performance has been analyzed based on its functionality parameters, accurate data reading and suitability of the assessment are the main parameters. The reading accuracy test yielded a difference of 0.474 X 10 -4 N, with an error percentage of 2.92% determined by using the Mean Absolute Percentage Error (MAPE) method. Data reading and suitability of the assessment have been tested and are able to run efficiently at 100%.


INTRODUCTION
The teaching aid is a learning messenger [1] that can help students to better understand both the concepts and the science processes that are being studied.The use of concrete media such as teaching aids to perform an experiment can provides a real and meaningful direct learning experience for students to be achieved [2].The teaching aids used in science lessons, such as the Lorentz force teaching aids were developed by Widyatmoko, Abdul Wahab, and Adi Cahyono.This prop can help students visualize the presence and direction of the Lorentz force directly, which has been proven to improve student's cognitive learning outcomes [3]- [5].
The Lorentz force experiment begins with the teacher preparing things such as prop, learning subject, and questions.Then, students are given instructions how to operate the prop.After experimenting with the Lorentz force prop, the teacher will give questions to evaluate student's understanding about what they did in the previous experiment.At last, the teacher assesses and recapitulates the results of the student's work.Heretofore, all these activities are still done manually.By implementing a technology, these activities can be done automatically and digitally.
Teaching aids are important in helping students understand abstract or inconceivable learning content directly [6].Lorentz force is an abstract physics topic and students commonly find it hard to understand [5].Several studies have developed Lorentz force teaching aids and it had been proven that it is able to improve student's cognitive learning outcomes.The result of research conducted by Adi Cahyono, Prabowo, and Setyo Admoko stated that on the level of completeness of students after participating in learning using Lorentz force experiment prop that shows the improvement of 94,32% in student's learning outcomes [4].The research is conducted by Lia Kristina Sianipar, Sunaryo and I Made Astra shows that the study obtained an average pre-test score of 29.17 and an average post-test of 82.78 that had been conducted on 27 students.This study concludes that the development of Lorentz force teaching aids manages to enhance student's cognitive learning outcomes [5].Abdul Wahab tested the normality (N-Gain) of the learning outcomes after using the Lorentz force teaching aid and obtained a score of 0.8 which were considered in the high category [3].Aspects that affect the enhancement in learning outcomes are due to the use of these teaching aids attracts student's attention, in such a way, students are unconsciously motivated to learn and fathom the fundamental concept of Lorentz force.
Studies have developed teaching aids to boost student's understanding of the Lorentz force concept, but there had been no research integrated with the latest technology development, particularly in IoT.Several studies have applied IoT to learning aids.Irvan Rahmanto, Novian Anggis Suwastika, Rahmat Yasirandi developed a prop that applies IoT to hopscotch game to stimulate the development of children's gross motor skills [7].The implementation of IoT into games to stimulate children's fine motor development was also carried out by Seiba Shonia, Novian Anggis Suwastika, and Rahmat Yasirandi by developing bag toss game integrated with IoT [8].Another study to support stimulus of children's gross motor skill in hopscotch using IoT is implemented by Riyan Kuncoro Jati, Novian Anggis Suwastika, and Rahmat Yasirandi [9].Also Muhammad Ilham Setiawan, Novian Anggis Suwastika, and Sidik Prabowo developed an IoT-based mathematics teaching aid for multiplication and division topic for 2 nd grade elementary school [10].
Along with the development of technology, Internet of Things (IoT) capable to facilitate the teaching and learning process [11].The Internet of Things would therefore be able to communicate data over a network without the need for human-to-human or human-to-computer contact [12].The implementation of IoT in the field of education also called Internet of Education Things (IoET) [13].IoET has many benefits in the teaching and learning process for both teachers and students in the form of hands-on learning experiences.The teacher's task is to focus more on monitoring students and assessing students quickly and precisely because reading activity can be saved automatically [14], therefore IoET is suitable to be implemented into Lorentz force prop (E-Lorentz).E-Lorentz could calculate the intensity of the Lorentz force and evaluate student's work determined by what they have practiced.Based on the parameters of assessing data reading accuracy and suitability of the assessment, this system evaluates the system's performance and functionality.

RESEARCH METHODOLOGY 2.1 Research Process
As shown in figure 1 down below, the research process starts with identifying the problem according to the topic that has been carried out.Then, conduct a literature review or preliminary search to see whether there is sufficient literature for the aims and to establish the study's context.After defining the problems and conducting a literature study, the research questions and objectives emerge.System design is now used to define the system's features, such as system architecture, components, interfaces, and testing scenarios.The system will then be implemented once all of the designs have been completed.This stage culminates in the development of the system's hardware and software.The system will then be tested using the testing scenario created in the previous stage.Afterwards, this study analyzes the result of the testing to conclude weather the system is in course with the objectives or not.Finally, this study writes a report that are based on the research results in a clear and concise manner.

E-Lorentz
Lorentz force is one of the topics in physics subject taught in upper secondary school, specifically 9 th grade.In the Indonesian's 2013 study curriculum, Lorentz force calculation does not take into account of the angles between magnetic field charge (B) and electric current (I) [15].In the learning process, teaching aids are used to help student better understand the concept of Lorentz force called E-Lorentz.The prop that is used in this teaching aid could show the presence and direction of the Lorentz force based on the elements that are affected by it [4].Fundamentally, the Lorentz force (or electromagnetic force) is the result of electromagnetic fields that combines electric and magnetic forces on a point charge.Lorentz force direction can be determined using the right-hand rule.The stronger the magnetic field (B) and current (I) value, the bigger Lorentz force value [16].The Lorentz force has the general formula, Where: The Lorentz force prop uses magnet to form magnetic field, power supply, and foil sheets or enameled wire.The magnet will form a magnetic field, power supply will produce an electric current, and the enameled wire or foil sheets will be hung between the magnets to indicate the Lorentz force presence.When the power supply is turned on, the current will pass through the magnetic field, Lorentz force will then be formed which is indicated by the movement of the enameled wire or foil sheet up or down which attached to the magnetic field.
Lorentz force experiment in class begins with the preparation of teaching aids, learning course content, and questions by the teacher.Students are given instructions regarding the use of the prop.Once students have tried out the Lorentz force prop, the teacher will give questions to assess their grasp of the experiment that has been done.Lastly, the teacher will recap the student's evaluation result to the student's record.

RESULTS AND DISCUSSION
This section will be discussed the system design, implementation result, and results of the testing that has been done based on the test scenarios that has been made.

System Design
In this section, system architecture, system flow, hardware design, software design, test scenarios are all described.

System Architecture
Figure 2 shows the architecture of the system.The system has two users, student and teacher.Communication used in the system is MQTT protocol which a reliable message delivery protocol using publish/subscribe architecture [17].Interface is built to let the user use the system.The teacher will access the interface with a personal computer or a laptop to send questions and to view student record.Students access questions using the interface to view and answer the questions, before the students answer the questions, student enter the information from the question using the keypad, then the KY-024 module will capture the analog signal and send it to microcontroller to be converted into digital signal.After that, the digital signal's value is converted into volt and turn it to magnetic flux density unit which is called Tesla.The microcontroller used in this system is ESP32.Microcontroller will process the Lorentz force value which will then be compared with the student's answers.The results are sent using the MQTT protocol and compared with student's answer stored in the database.If the student's answer is equal, the answer is declared as correct and the total correct answer will be used as the student's score.The teacher views the results on the student's record interface using a personal computer or a laptop.

Flow System
The E-Lorentz system has two users who play the roles in the system, they are the teacher and the student.Figure 3 shows system flow of teacher.The teacher sends questions from the interface provided after logging into the application.Questions sent by the teacher will be stored in the database.Teachers can see student's scores on the student record page.In figure 4, student user flow is described.After logging in to the application, questions will be displayed and students enter information from the question in the form of quantities that affect the Lorentz force such as current value, length of wire or foil sheet.The amount of current is obtained from the multimeter reading of the current source.Students answer questions based on known quantities and write answers in the interface, student answers will be stored in the database.The system will process data that came from the sensor to be used as the magnetic flux density quantity.Lorentz force value will be generated from all processed data.After that value will be sent using MQTT protocol.The value will be published to the broker, then will be subscribed by the system to be stored into the database.The system will compare the student's score with the value generated by E-Lorentz.If the answer equal, the total score will be added one.The total score is taken from the total correct answer.It will be recorded in the student's record.  Figure 4 explained how students use the system.Students required to login into the application, then questions will be retrieved from the database and students can access questions and answers in the provided entry box.Before students answer the questions, students input the current value and wire length to E-Lorentz using a keypad.E-Lorentz will calculate Lorentz force value result and publish it to the broker using the MQTT protocol.The system will receive the result by subscribing the topic and store it in the database.After students answer the questions, the system will compare student's answers with E-Lorentz results.If the answers are the same then the score will be added by one.Student's score will be calculated and stored in the database.

Hardware Design Figure 5. Block Diagram
In figure 5, a block diagram of E-Lorentz or device arrangement is described.The device functions are described in the table 1, The KY-024 module detects the analog signal of the magnetic field [18] and sends it to the microcontroller.The microcontroller uses ESP32 to convert the analog signal to digital signal.The digital output is converted in the form of an electric voltage which would later then be converted into magnetic flux density unit in which it is called Tesla.The results of the magnetic flux density can be seen from the LCD.

Software Design
The purpose of a Graphical User Interface (GUI) is to provide a system that can assess student's comprehension, read, and analyze data.Here is an overview of the interface.

Figure 6. Login Interface
Login page in figure 6 is used so that both the student and the teacher could enter the system.If the employee identification number (NIP) or student identification number (NIS) and password do not match, the user cannot access the system.The questions upload page is intended for teachers to create questions that students will answer.The 'List Nilai' button is used to view student's records such as NIS, name, class, and student test score.The question page is used for students to answer questions.Student will enter the answers to the questions into the provided entry box and when they have finished answering the questions, the students will press the next button to move the next question until the questions have been answered.Teacher can add student data in this page.'Upload Soal Guru' button will direct the user to the upload questions page.

Test Scenarios
The system will be tested based on the functionality and performance.The functional testing will be divided into two parts.Hardware functional testing will be tested based on table 1 functionality and software functional testing will be tested by testing it on 2 students, each student will try to answer the same questions.The result of the test will be compared whether the system emits the supposed score or not.The reading accuracy of the system will be assessed as the performance system testing.

Implementation Result
Figure 10 is an E-Lorentz prototype that had been built according to the design in figure 5. Lorentz force prop are shown with foil sheet as an electric conductor, a power supply as a current source, and a magnet to produce a magnetic field.The KY-024 module detects the magnetic field and sends analog data to the microcontroller.

Hardware Functionality Test Results
The results of the prop functionality test can be seen in table 2. The test parameters are obtained from the results of the functionality analysis of how the system should work.In testing, the prop work 100% based on the parameters that had been made.Providing resources (V) 100%

Software Functionality Test Results
Functionality test on the software was carried out within two students that answers 5 questions using E-Lorentz.5 describe the questions that submitted by teacher, answers from the students, and also the system output result.Then, the answer from the rating system will be determining result on whether the system evaluate the answers correctly.Based on the rating system answer, system could accurately assess the answers based on the provided questions.

System Performance Test Results
The results of reading accuracy of the system are shown in Table 6.Based on the system reading accuracy on Table 6, the average value of the distinctness is 0.474 x 10 -4 N.This result is obtained by comparing the Lorentz force value according to E-Lorentz and manual calculation.With the use of Mean Absolute Percentage Error (MAPE), which aims to find the average error percentage, the result is 2.92%.

CONCLUSION
In this study, a system was developed to satisfy the needs of teaching and learning, particularly in the Lorentz force subject course.Students not only can practice the Lorentz force presence, but also be able to calculate the intensity of the Lorentz force that they have practiced.It could also read student activity automatically to assists teachers in obtaining the assessments of their students.Several test scenarios were carried out, one of which is by testing the functionality of the hardware and software as well as the precision of reading accuracy.The reading accuracy test yielded a difference of 0.474 X 10 -4 N, with an error percentage of 2.92% determined by using the Mean Absolute Percentage Error (MAPE) method.The accuracy of the accurate assessment of the answers given by the students and the parameters that have been made to test the functionality of the prop revealed that the implemented system is able to operate 100% capacity, based on the results of testing the functionality of the hardware and software.

Figure 3 .
Figure 3. Teacher User Flow Figure 3 explained how the teacher uses the system.The teacher first logs into the application, the teacher write questions into the provided entry box.After logging in, the teacher can also view student records consisting of the student identification number (NIS), name, class, and student scores by clicking the list score button.

Figure 7 .
Figure 7. Submit Questions Page

Figure 9 .
Figure 9. Student's record Page The student's record page is used to show student records such as NIS, name, class, and student's test score.Teacher can add student data in this page.'Upload Soal Guru' button will direct the user to the upload questions page.

Table 5 .
Student Application Functionality Test Results 2

Table 6 .
Reading Accuracy Test Results