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Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.Xây dựng và sử dụng thiết bị thí nghiệm trong dạy học các kiến thức về phóng xạ (vật lí lớp 12) theo hướng bồi dưỡng năng lực thực nghiệm của học sinh.
MINISTRY OF EDUCATION AND TRAINING HA NOI NATIONAL UNIVERSITY OF EDUCATION LE ANH DUC CONSTRUCT AND APPLY EXPERIMENTATION IN EDUCATING RADIATION OF PARTICLE NUCLEAR (GRADE 12TH PHYSICS) TO DEVELOP EXPERIMENTAL COMPETENCIES OF STUDENTS Major: Philosophy and Methodology in Physics Code: 9.14.01.11 DOCTORAL THESIS IN PHILOSOPHY OF EDUCATION HA NOI – 2022 THIS WORK WAS COMPLETED AT HANOI NATIONAL UNIVERSITY OF EDUCATION Scientific Instructors: Assoc Prof Dr Nguyen Ngoc Hung (Hanoi National University of Education) Dr Tran Ngoc Chat (Hanoi National University of Education) Reviewer 1: Prof Dr Le Thi Thu Hien, VNU University of Education Reviewer 2: Prof Dr Nguyen Thi Nhi, Vinh University Reviewer 3: Dr Cao Tien Khoa, Thai Nguyen University of Education This thesis will be presented and defended at the Thesis Examination Board meeting at Hanoi National University of Education at The thesis is available at: National Library of Vietnam, Hanoi or Hanoi National University of Education’ Library LIST OF SCIENTIFIC WORKS RELATED TO THE DISCLOSURE OF THE THESIS Le Anh Duc, Tran Ngoc Chat, and Nguyen Ngoc Hung Evaluating experimental competence of 12th-grade students in Vietnam through teaching methods using radioactive experiments.1st international conference on innovation in learning instruction and teacher education, Conference proceedings, Hanoi National University of Education (HNUE), 2019 Anh Duc Le, Quoc B Nguyen, Ngoc Chat Tran, and Ngoc Hung Nguyen A remote-controlled detector system with Geiger–Müller counter Physics Education 56(2), 025021, 2021 Le Anh Duc, Vu Ta Quyen, Pham Vo Trung Hau, Dinh Cong Minh & Nguyen Phuong Kha Tran Surveying a number of radioactive concepts of Physics specialized students Ho Chi Minh City University of Education Journal of Science, 18(5), 840, 2021 Le Anh Duc, Pham Thien Loc and Tran Ngoc Chat Design and manufacture of radioactive detection equipment by sparks used in teaching on alpha -beta radioactivity The 5th National Conference on Teaching Physics, Hanoi National University of Education, 2021 Le Anh Duc, Nguyen Minh Duy, Nguyen Quoc B, Tran Ngoc Chat, and Nguyen Ngoc Hung Improving the Wilson Cloud Chamber Using Peltier Chips The Physics Teacher, 60(1), 62-65, 2022 Le Anh Duc, Tran Ngoc Chat, and Nguyen Ngoc Hung Building general experimental competence structural framework of physics Ho Chi Minh City University of Education Journal of Science (Accepted) INTRODUCTION The reason for the themes chosen - Since 2018, the high school curriculum has set new goals in educating students including creating, nourishing desirable qualification and essential competencies for students - In Science subjects, particularly in Physics, when planning teaching activities, teachers must be aware of providing students with typical competencies of Physics, especially experimental competencies - Moreover, in curriculum of Physics for high school students in Vietnam, there have not been any experiments covering radiation in teaching The teaching methods has been mainly announcing - receiving ever since Experiments about radiation will be capable in creating opportunities and environments for students to acknowledge and develop their experimental competencies - In order to fully create and develop all components of experimental competencies, not only organizing students to conducting pre-designed experiments with pre-designed apparatus should be applied, but guiding them to research, design, construct apparatus and applying them in experiments on their own are also considered as important Based on mentioned arguments, I have chosen the topic of “Construct and apply experimentation in educating radiation of particle nuclear (grade 12th physics) to develop experimental competencies of students” as my doctorate dissertation Purpose of the research Research the planning, guiding procedure for student to construct (design, create, improve and finish) and use apparatus in learning knowledge of radiation of particle nuclear (grade 12th physics) to develop experimental competencies of students Subjects and scopes of application ❖ Subjects of application - Experimental skill of students - Process of teaching Problem-Based-Learning (PBL), particularly process of guiding student to construct and use Physics-relating-apparatus in PPL ❖ Scope of application - Degree of content: Knowledge of Physics in lasts grade 12th Physics curriculum and in 2018 grade 12th Physics curriculum - Process of teaching PBL the knowledge of radiation and process of guiding student to construct and use apparatus in studying the knowledge - Structure of experimental skill in studying radiation Scientific hypothesis If constructing and guiding student to construct experimental apparatus can meet the demands of standard experimental apparatus and can be used appropriately in teaching PBL the knowledge of radiation of particle nuclear (Grade 12th Physics), the experimental competencies of students can be nourished Objectives of research To achieve the mentioned aims of dissertation, the dissertation will have these following objectives: - Research the argument in teaching Physics for nourishing competencies, particularly experimental competencies; the argument in constructing and using apparatus in teaching PBL - Research the curriculum, official handbooks about for grade 12 th Physics about radiation of particle nuclear, which are latest and in 2018 to identify the contents of radiation and experiments required in the teaching contents - Know the actual situation in teaching knowledge of radiation on grade 12, including: teaching methods of teachers; learning methods of students; actual state of experimental apparatus and methods of applying those in teaching knowledge of radiation; common difficulties in teaching knowledge of radiation and mistakes in learning about radiation by students - Plan a procedure in deploying contents aiming at teaching PBL, which also covers the process of guiding students to construct experimental apparatus for the experiment of radiation - Conduct pedagogical practice in teaching planned contents about radiation, particularly guiding students to construct and apply experimental apparatus for the experiments Researching methods To achieve the mentioned aims of the dissertation, the following researching method has been applied - Theoretical researching method - Actual surveying method - Laboratory testing method - Pedagogical practice method - Mathematical statistic method to process the gathered result from pedagogical practice New Contributions of the thesis - Help completing, perfecting the structure of experimental competencies and propose some general solutions in nourishing experimental competencies of student in teaching Physics - Research and construct (design, create or improve) experimental apparatus: Cloud chamber with dry ice; cloud chamber with thermoelectric coolers (Peltier chips); Alpha-Beta radiator with electric spark; radioactive detector with Geiger counter; and remote detector system controlled by Wi-Fi Those apparatuses can be applied in experiments such as: Experiment to test the probability of radiation; experiment to test properties of ray; experiment to test properties of ray; experiment to test the penetration of ray; experiment to test laws of radiation; and experiment to illustrate the basic principles of technical Gamma scanner to identify flaws in integrity of material and congestion in pipes - Plan a procedure in deploying contents (Grade 12th Physics) aiming at teaching PBL, which also covers the process of guiding students to construct experimental apparatus for the experiment of radiation, aiming at develope experimental competencies in students - Apply general structure of experiment competencies to construct a specialized structure of experimental competencies of student, which is required to be nourished when researching contents of radiation CHAPTER GENERALIZATION OF RESEARCHING ISSUES 1.1 Research about competencies 1.1.1 Definitions of competency General high school curiculum in 2019 has defined that: Competency is an individual attribute that is formed and developed thanks to inherent qualities and the process of learning, training, allowing people to acquire knowledge, skills and other personal attributes such as inspiration, belief, determination to successfully perform a certain type of activity, achieving the desired result under specific conditions 1.1.2 Structure of competency According to authors Nguyen Van Bien, Do Huong Tra, determine the structure of experiment competencies includes: - First: Define (Describe the content) experimental competencies - Second: Identify the fields, factors and components that make up that competency - Third: Determine the behaviors of each elements - Fourth: Determine the degree of quality level the behaviors 1.1.3 Teaching to nourishing and develop competency According to Do Huong Tra et al, teaching Physics is not only teaching knowledge but also training student competency in applying knowledge of Physics in understanding and solving real-life problems Teachers must choose appropriate methods that is advantagous in developing each specific elements of particular competency, creating environment to concentrate on evaluating the component competencies Activities taking place in the lesson need to be diverse, creating many opportunities for students to show the behaviors which are identified in the requirements to achieve competence From the argument of teaching Physics: The core of success in developing competence is that teachers must deliberately choose learning topics, then organize situations to bring learners into learning activities, or problem solving 1.2 Precedent research about experimental competency Eickhorst et al have suggested that "experimental competence" includes actions: planning and performing experiments to clarify a physical question, and meaningfully evaluate the results, the data that has been achieved According to the Metzger et al: Experimental competencies are structured by component competencies that refer to many different types of problems such as observing, measuring, understanding, researching, evaluating the possible measures or solving problems Documents from OCR refer that "practical skills" include the following component skills: planning for experiments, conducting, analyzing the results and making conclusions Schreiber, Theyßen and Schecker believed that experimental competency includes the following components: Planning research, capability to conduct experiment, capability to evaluate Xayparseut Vylaychit defines: Experimental competency is the ability to deploy gathered knowledge, skills and techniques, combining with psychological attributes such as excitement, belief, and determination to successfully perform experimental objectives Some studies on the construction and use of experiments in teaching and researches on methods of fostering and evaluating experimental competencies include: + Nguyen Van Bien offer process of teaching experiments to foster the experimental competencies of gifted students + Nguyen Thi Nhi proposes a some measures to foster experimental competencies for pedagogical students of Physics such as: Organizing teaching activities of modules with experimental practice; guide students to construct experimental apparatuses; innovate the assessment method + Xaypaseut Vylaychit offers measures: Constructing learning tasks associated with experimental activities to develop student experimental competency, constructing and perfecting experimental apparatuses to support experimental activities, organizing teaching according to PBL in teaching new knowledge and in teaching with technological application, constructing experimental exercises and using tasks associated with activities to solve experiments 1.3 Research in constructing and using radioactive experimental apparatus in foreign countries 1.3.1 Research in using experimental apparatus pre-made by the manufacturer By researching the catalogs of the experimental apparatus manufacturers such as Phywe, Pasco, Leybold, Canberra we have obtained results about the radioactive experiment apparatuses such as Wilson cloud chamber, Geiger-Müller (G-M) gas counter, NaI detector, Gamma radioactive source, low intensity Alpha-Beta radioactive sources The common point of the apparatus sets manufactured by foreign manufacturers is the integration of many functions If only using these apparatuses in teaching, only certain elements of experimental competency are achieved Secondly, these experimental sets also include radioactive sources, which is forbidden to be sold outside of the host country Thirdly, the radioactive experimental equipment is very costly 1.3.2 Research in using experimental apparatus in teaching at many countries and self-constructed experiment There have been many studies in self-constructing low-cost experimental apparatuses such as: Ionization chamber to study radiation in the atmosphere, GeigerMüller counter tube to record ionizing radiation at different locations near the Earth's surface, cloud chamber using dry ice as cooler combining with common items such as glass, fish tank These articles lack information about issues that uses may encounter when constructing and conducting experiments, as well as some possible solutions to overcome those problems 1.4 Issues required more research From the mentioned precedent research, some issues that need to be studied more thoroughly can include: - Researching, completing, and perfecting the structure of experimental competencies, especially in the case where students are assigned with tasks of designing and constructing experimental apparatuses to conduct the required experiments - Based on the high school curriculum of Physics for grade 12th student, determine the contents of radiation that students are required to learn to determine the content of the required experiments and the experimental apparatuses that needs to be constructed and used in those experiments - Planning process of guiding students to construct some experimental apparatuses so that they meet the standard requirements of experimental apparatus used in teaching Physics and fostering student experimental competencies - Drafting the process of teaching knowledge of radiation according to PBL, including the process of guiding students to construct experimental apparatuses and use them to conduct required experiments CHAPTER THEORETICAL AND PRACTICAL BASIS OF CONSTRUCTING AND USING RADIOACTIVE EXPERIMENTAL EQUIPMENT IN TEACHING RADIATION TO FOSTER THE EXPERIMENTAL COMPETENCIES OF STUDENTS 2.1 Experimental competency 2.1.1 Definition of experimental competency Based on the study of the definitions of experimental competency in the Overview and the definition of Competency in the General curriculum by the Ministry of Education in 2018 [1], we detail the definition of experimental competency as: “Experimental competency is the ability to synthesize knowledge, skills and psychological attributes such as excitement, belief, determination… to successfully perform certain experimental tasks, achieve desirable results under certain conditions or contexts” 2.1.2 Structure of experimental competency The structure of experimental competency includes following elements: Determine the purposes of experimentation; design experimental plans; implement results of the experiment; draw conclusions and improve the experiment The structure of experimental competency needs to be supplemented with behavior index corresponding to the case where no experimental equipment is available, students need to design and construct experimental apparatuses to perform the experiment to achieve the defined experimental purposes • Two facilities to supplement new behavioral indicators to the structure: - Based on the process of conducting experimental activities of conductors - The structural frameworks of experimental competency from the presciently researched studies are completely unavailable, or the behavior of constructing new experimental apparatuses in case of no availability ones is not specified Therefore, experimental competency generally has the following structure: Table 0.1 Structure of experimental competency Element Index Determine the NLThN1.1 Determine the purposes of experimentation purposes of successfully experimentation NLThN2.1 Analyze, identify knowledge relating to the experiment NLThN2.2 Identify required experimental apparatuses a) Case 1: Required b) Case 1: Required apparatuses apparatuses are are NOT available or pre-made available or pre-made NLThN2.3 Research the required NLThN2.3 Research the apparatuses through catalogs, provided apparatus documents, articles NLThN2.4 Design required NLThN2.4 Determine apparatuses Design the layout of the experimental NLThN2.5 Prepare material for experiment plans construction NLThN2.5 Plan steps to NLThN2.6 Construct components conduct experiment of apparatuses NLThN2.7 Assemble components according to the planned design NLThN2.6 Determine NLThN2.8 Provide, modify what qualitative or details of apparatuses during quantitative experimental construction data that should be NLThN2.9 Determine the layout collected of the experiment with new apparatus Conduct experiment Draw conclusions and improve the experiment NLThN2.10 Plan steps to conduct experiment NLThN2.11 Determine what qualitative or quantitative experimental data that should be collected NLThN3.1 Assemble, arrange apparatuses NLThN3.2 Conduct experiment NLThN3.3 Overcome errors in experiment NLThN3.4 Collect qualitative and quantitative experimental data NLThN4.1 Process the data NLThN4.2 Draw diagram NLThN4.3 Draw conclusion NLThN4.4 Assess and provide improvement for experiment 2.1.3 Level of behavior index in experimental competency Intellectual acts (speaking, writing, drawing ) will be classified according to the SOLO taxonomi (the structure of the learning results can be observed), we divided into levels: - Level (unistructural): perform simple, specific behavior at low awareness level - Level (multistructural): Can solve some independent and discrete issues Students can classify ideas but loose ideas, not yet combined - Level (relational): It is possible to understand the relationship between some aspects and how they can combine to form a whole Students perform full and accurate behavior Acts, activities, manipulation of manual will be classified according to the levels of the Dreyfus frame about the skills of skills: - Level (advanced beginner): Perform sequential operations when there is guidance and supervision - Level (competent): performing the action of action is not mature but there is no need for guidance and achieving certain accuracy - Level (proficient): Action operations are proficient and accurate 2.2 Current situation of teaching some radioactive knowledge in high schools and students' concepts about radioactivity in Vietnam 2.2.1 Actual circumstance in teaching knowledge of radiation in High school in Vietnam Many teachers not know about radioactive experiments, their teaching methods are mainly presentations, announcing - receiving and guiding students to solve quantitative exercises The results of the interviews with students about the methods, ways and forms 10 CHAPTER CONSTRUCTION AND USE OF EXPERIMENTAL APPARATUSES IN TEACHING KNOWLEDGE OF RADIATION 3.1 Analyze aims of teaching knowledge of radiation in grade 12th curriculum According to the latest 12th grade Physics curriculum and the 2018 Physics curriculum, the knowledge of radiation sets out the requirements of competency as follows: Table 0.1 Requirements of competency in teaching the knowledge of radiation Latest 12th grade Physics curriculum 2018 Physics curriculum - Able to state the spontaneity and probability of radioactive decay - Able to define intensity of radiation, - Able to state the definition of radiation constant and able to apply relation radioactivity and the nature of H = λN radioactive rays - Able to apply formulation x = x0.e–t, with x - Able to state the law of radiation and is intensity of radiation, number of non-decay write down the relation of this law particle or speed of counted particle - Able to state the intensity of - Able to define radiation half-life radiation, write down formula to - Able to describe some general properties of calculate it α, β và γ radiations - Able to list the applications of some - Able to know the appearance of radiation by radioactive isotopes common signals - Able to state the safety measures of radiation; obey those measures In general, the content of knowledge about "Radiaction" in both curricula has not changed much In our opinion, the requirements for the competencies that students need to achieve when learning the knowledge of this section are only at beginner level: define, describe, recognize, state; apply formulas to solve quantitative problems The goals of fostering student competencies at a higher level such as applying, analyzing, evaluating and creating are not mentioned Therefore, the content of radiation parts needs to be provided with the goal of fostering competencies, particularly the goal of fostering competencies of PBL including experimental competency Moreover, it is required to include technical application of knowledge of radiation into teaching 11 3.2 Contents of knowledge of radiation and experiments of radiation in required in teaching Table 3.2 Contents of knowledge of radiation and experiments of radiation in required in teaching Required knowledge of radiation Required radioactive apparatuses - Probability of radiation Detector with G-M counter + γ radiation sources - Ionizing ability, capable travelling Cloud chamber or radiation detector by distance and penetration of α ray electric sparks + α radiation sources - Ionizing ability, capable travelling Detector with G-M counter + β distance and penetration of β ray radiation sources - Penetration of γ ray Detector with G-M counter + γ radiation sources - Experiment to test the expression of laws Detector + γ radiation sources with short of radiation half life - Experiment to illustrate some technical Detector with G-M counter + internally applications of radiation defected object + γ radiation sources 3.3 Construction of apparatuses for radioactive experiment The conduct of experiments requires corresponding experimental equipment Because currently, experimental apparatuses for radioactive experiment is not available in high schools Therefore, based on findings about available experimental equipment in foreign countries, analysis of the feasibility of constructing them, we have studied to design construct apparatuses 3.3.1 Radiation sources + Natural soil samples containing small amounts of radioactive isotopes of Uranium, Radium emitting α and β rays + Strontium radioactive source (Sr-90) / β-ray emitter is borrowed from the Nuclear Center of Ho Chi Minh City + γ radiation source (Co-60, Cs-137 ) at the Nuclear Physics Laboratory of Ho Chi Minh City University of Education + Technetium radioactive source (Tc-99m) with half life of hours was borrowed at Hospital 175, Ho Chi Minh City to conduct experiments to test the law of radiation The radioactive sources that students use in the experiments have all been tested for safety according to Vietnamese and Global standards 3.3.2 Cloud chamber a) Functions: Cloud chamber is used to record and observe the trajectory (trace) of α, β radioactive rays It can also be used to conduct experiments to test some properties of -rays and -rays such as ionizing properties, travelling distance, penetration b) Constructing cloud chamber 12 The choud chamber is made from a cylindrical glass container with a bottom radius and height from 5cm to 7cm Commercial glass food containers can be used Figure 0.1 Drawing of cloud chamber operated by dry ice (Left) and cloud chamber operated by Peltier chips (Right) With the cloud chamber, we can conduct experiments to test the ionization ability of , β rays based on the explanation of the operating principle of the cloud chamber Observing the radioactive ray by vapor trails in the chamber allows to estimate the travelling distance by the -ray in the mist environment which is a few centimeters Finally, we can observe the penetrating Figure 3.2 Traces of radioactive rays power of the -rays by placing thin sheets of inside cloud chamber paper that block the path of -rays inside the cloud chamber 3.3.3 , β radiation detector by electric sparks a) Function: Detect , β radioactive rays by creating sparks and crackling sounds when , β rays hit the apparatus High pressure ignitor can used in experiments to clarify the penetration of particles ; experiments to test the travelling distance of particles in the air b) Construct high pressure ignitor: The apparatus consists of: Battery (1) has an output voltage of 3.7V; switch for turning on and off apparatus; 50KV boosting module, also known as boosting circuit, high voltage boosting module; positive and negative electrodes (Anode and Cathode) 13 Figure 0.3 High pressure ignitor Battery Boosting module Switch Cathode Anode 3.3.4 Detector with Geiger- Müller counter a) Functions: - Detect and record γ radioactive ray, some types of tubes can record β ray - This experimental apparatus is used to conduct the following experiments: Experiment to clarify probability of radiation; experiment to test penetration of β and γ ray; experiment to test the expression of laws of radiation and experiment to illustrate some technical applications of γ radiation in identifying internal defect of material b) Construct detector with G – M counter: The detector with the G-M counter made by us includes the following main parts: the G-M counter (1), the Arduino control board and the Multi-Funtion Shield circuit (2), the boosting circuit (3) and the power supply (Can be from battery or Adapter - 4) Figure 0.4 Components of detector with G – M counter In order to accommodate the storage and conduct of the experiment, all the mentioned parts above are put in a box The battery is replaced by power from the 9Volt Adapter Figure 0.5 Front and back view of detector with G – M counter G-M counter tube; The protective cap of the counter; The 9-Volt adapter supplying power for the detector; The display showing the count; Time setting buttons; detector Reset button 14 Results and implementations: ❖ Experiment to test penetration of β ray Results: + When placing a thin sheet of paper between the β radiation source and the counter, the counts recorded by the detector is almost unchanged + When placing a plastic or aluminum plate with a thickness of 1mm between the β radiation source and the counter, the recorded counts are significantly reduced, but there are still some β rays that penetrate the material to the detector and are recorded + Put a lead plate with a thickness of about 1mm between the β radiation source and the counter, the count decreases to β radioactive rays not penetrate the lead plate ❖ Experiment to test penetration of γ ray Results: + The greater the thickness of the material, the greater intensity of the γ-ray gradually decreases, and with a sufficient thickness, the entire γ-ray can be blocked completely + The ability of γ-rays to penetrate through a material depends not only on the thickness of the material, but also on the substance of the material 8mm of lead is already able to block all γ rays while plastic requires a thickness of more than 24mm to the same + Comparing with the penetration of α and β rays studied in previous experiments, γ rays have much greater penetration than α and β rays ❖ Experiment to test the expression of laws of radiation and values of radiation constant, half-life of radioactive substances Figure 0.6 Activity of radioactive substance H decreases with time of Tc-99m radioactive source 15 Matched function expresses law of radiation (H = 𝜆 𝑁0 𝑒 −𝜆𝑡 ) in the graph, showing that the change of H with time t has the form of this function By reading the values of the decay constant λ and the half life T obtained from the graph of experiment and comparing it with the values of λ and T of the source Tc-99m, they are approximately the same λ=0,0000305 s-1 T =22741,35 (s)=6,317 (h) ❖ Experiment to illustrate technical application of radiation by using Gamma rays to identify internal defects inside material Figure 0.7 Layout of the experiment to use Gamma rays to identify internal defects inside material Result: It is possible to identify the internal defect inside the material by experiment to illustrate the basic principle of the apparatus using γ-ray to identify defects inside the material The number of pulses when the -beam penetrates the pore (defective) position of the iron block will be larger than when the -beam passes through other locations without defects 16 CHAPTER DESIGN PROCESS OF TEACHING PBL THE KNOWLEDGE OF RADIATIONS AIMING AT FOSTERING EXPERIENCE COMPETENCY OF GRADE 12TH STUDENT The process of teaching knowledge of radiation, including the process of constructing and using experimental equipment according to PBL will be presented including: - The process of teaching "Radioactive phenomena - Types of radioactive rays" is the application of teaching PBL with a stage to find out PBL leads to new knowledge in the history of Physics research - The process of teaching "Law of radiation" is the application of teaching PBL in a theoretical way - The process of teaching with technical application "Technical equipment using gamma rays to identify internal defects inside materials" is the application of the teaching PBL with technical application in Physics according to 1st way The three teaching processes above will all be presented with the same outline: Process of knowledge-building → Process of specific teaching → Rubrics to assess student experimental competency in the process of learning knowledge Raises a problem that needs to be solved • 17 Students can identify types of radioactive rays ( rays, β rays, and γ rays), distinguish the nature and properties of each type of PX rays Students identify the purposes of the experiment: test some properties of α and β radiation (NLThN1.1) • Design experimental plan to test some properties of radioactive rays (α and β rays) • Students look up radioactive experimental apparatuses on the internet and identify some apparatuses: Cloud chamber, detector (Using G-M counter, NaI counter) (NLThN2.2, NLThN2.3) Students design cloud chamber in form of drawing (NLThN2.4) Students prepare material for construction of the apparatus (NLThN2.5) • • Student must design Construct cloud chamber and conduct experiment to test some prioperties of radioactive rays (α and β rays) and construct the cloud • • • • Students construct and assemble the cloud chamber and run testing (NLThN2.6, NLThN2.7) Students identify errors and overcome, fix the apparatus to conduct experiment (NLThN2.8) Students explain the working principle of the chamber Students propose plan of experiment to test the penetration of ray with the cloud chamber and conduct the proposal (NLThN2.9, NLThN2.10, NLThN3.1, NLThN3.2) chamber Conclude and improve the experiment • • Students draw conclusions about the properties of ray (NLThN4.3) Students improve the apparatus and experiment (NLThN4.4) Diagram 4.1 Diagram of the process of teaching PBL "Radioactive phenomena - Types of radioactive rays - Test some properties of radioactive α rays" to foster the experimental competency of students ... achieve the mentioned aims of the dissertation, the following researching method has been applied - Theoretical researching method - Actual surveying method - Laboratory testing method - Pedagogical... students to construct experimental apparatuses and use them to conduct required experiments CHAPTER THEORETICAL AND PRACTICAL BASIS OF CONSTRUCTING AND USING RADIOACTIVE EXPERIMENTAL EQUIPMENT IN... of Physics The process of building knowledge according to PBL can happen in one of two ways: The theoretical way and the experimental way In case that the process of building new Physics knowledge