Since the 1980s, under the impetus of information technology represented by multimedia, computers, and the Internet, human society has increasingly entered the information age. In the information-based environment, great changes have taken place in many aspects such as educational concepts, teaching objects, teaching objectives, teaching models, teaching processes, and media means in school education. The core of this reform is the innovation of the teaching model. The concrete manifestation is that the class-based teaching system emphasizing knowledge transfer and teaching-based knowledge transfer models gradually gives way to the problem-centered, school-based integration based on the information environment. Inquiry mode.
In the last ten years, the concept of flipping classrooms (translated from flippedclassroom or translated classroom, also translated into reverse classrooms, reversed classrooms) has been accepted by more and more schools in North America and gradually developed into a wave of education and teaching reforms. tide. Especially in the past two years, "Wall Street News" and transfer classes have given enthusiastic attention and positive reports. Compared with flipping the classroom, which has become a hot topic in the education field in North America, there is relatively little attention to the flipping classroom in China. Currently, only Zhang Yueguo et al. (2012), Sang Xinmin et al. (2012), Zeng Zhen (2012), and Zhang Jinlei et al. ( 2012) Made a systematic introduction or commentary on flipping classes. To flip the classroom from the practical exploration and development of a few researchers to an innovative teaching theory in the information environment, we must first provide a practical instructional design model, transform the old classroom and obtain a better teaching effect. . In view of this, this article tends to regard the flipping classroom as a kind of instructional design theory that subverts the traditional teaching process in the informational environment.
The development and evolution of instructional design Instructional design is based on the teaching theory, based on the characteristics of teaching objects (specific learners), organizing teaching content and teaching resources, designing teaching activities and learning environment, and ultimately supporting learners to effectively achieve learning objectives. System activity.
Instructional design aims to solve practical teaching problems and is a bridge connecting teaching theory with teaching practice.
Form: The evolution from a simple linear process to a complex open system The early instructional design pattern has obvious linear characteristics of analysis, design, development, implementation, evaluation, and other stages. This is clearly reflected in the Dick-Kerry, ADDIE, ASSURE, and effective instructional models. Although the Kemp mode is presented in the form of a ring, it can be designed in a step-by-step manner without a linear structure. However, the Kemp mode is still carried out within the closed system within the teaching. The new generation of instructional design models not only focus on the analysis of learners and teaching content, but also focus on the design and development of learning resources. They are also more concerned with the use of information technologies such as the Internet and effective communication mechanisms to create problem situations and provide external information in an open environment. Resources and intellectual support.
Content: From knowledge transfer to support learning activities, the early stage of instructional design is knowledge-centered, and the interest is in the strategy of knowledge transfer. Specifically, the teaching activities are what the teacher wants to teach, what the student learns, and how the teacher teaches. How students learn. Regardless of Robert Gagne's detailed learning analysis of the conditions, the design from the knowledge unit (Gao Ruili, 2003). Constructivist learning environment theory, flipping classroom theory, and blended learning theory put the learner's learning activities at the center. Around the learner's learning activities, there are resource environments and operating mechanisms that facilitate the exploration of problems, the construction of knowledge, and the enhancement of capabilities.
Since the 21st century, a new generation of information technology, constructivism and macro-social education system theory, and international open education resource movement have provided the technical environment, revolutionary ideas, and open resources for the education and teaching reforms in the information environment. It has played an important role in promoting the emergence and rapid development of classrooms.
(I) The background and origin of the flipped classroom The first is a new generation of information technology represented by mobile internet, internet of things, and cloud computing. It has not only produced a tremendous impetus for the reform of education and teaching systems, but also produced innovative teaching models. Provides ubiquitous and convenient technical support. The second is the influence of the constructivist theory and the macro social education system theory. Constructivism theory is not repeated here. The theory of macro-social education system was put forward by Banathy and Reigeluth, and advocated paying attention to social transformation and its profound impact on education. To solve education problems, we must look at the entire social system to think about issues and seek Solutions that go beyond the limitations of operating within the education and teaching system alone. The third is the promotion of the international open education resource movement. In 2001, the Massachusetts Institute of Technology (MIT) launched the Open Course Software Project (OCW), which opened the prelude to the Open Education Initiative (OER) campaign (Jian Jianli et al., 2011). The video open classes, Khan Academy, and TED videos that have become so popular around the world in recent years are increasingly becoming an important part of the learning ecosystem in the information age, providing innovative ideas for the design, development, sharing, and application of the curriculum.
As early as the early 19th century, General Sylvanus Thayer had attempted at the West Point Military Academy to allow engineering students to use the relevant materials to prepare for the core contents of class lectures before class; in the class, the class activities centered on the students' learning preparation combined with critical thinking. Training, to carry out the group's interactive activities to solve the problem, rather than the teacher's lecture. However, this approach did not cause concern and promotion. It now appears that the reasons are not related to the lack of technical means and related resources (Zeng Zhen, 2012). Flipping the classroom as a concept was clearly literary magazine published two articles in this area. Baker (2000) also published an article on related topics at the 11th International Conference on University Teaching held in Jacksonville, Florida. In these articles, the flipped classroom ("inverted classroom" or "classroomflip") was proposed as an independent concept. Around 2010, Salman Khan, the founder of the Khan Academy High School in Colorado Forest Park, United States, gradually became the leader in the field of flipping classroom practice. By their usual "flippedclassroom"
The influence is now more often used in the so-called flipping classroom. In the information environment, curriculum teachers provide teaching resources as the main form of learning resources. Students complete the viewing and learning of learning resources such as teaching videos before class. A new type of teaching model where students complete activities such as homework answering, collaborative inquiry and interactive communication in class.
Compared with the traditional teaching model, flip classroom has the following characteristics: First, from the perspective of the teaching process, the flip classroom subverts the teaching process of “teacher teaching + student assignmentsâ€. Traditional teaching usually involves two stages: knowledge transfer and knowledge internalization. In the stage of knowledge transfer, teachers complete the explanation of the course content in the course. Students complete the acceptance and preliminary understanding of the course content. In the stage of knowledge internalization, students Students use their knowledge to complete their homework and exercises and strengthen their understanding of knowledge. The flipping class puts the process of imparting knowledge under the class. Students complete the self-study of the course content before class. The process of internalizing knowledge is placed in the class. Most of the time in the class is used for students' homework. Collaborative inquiry and in-depth exchanges between teachers and students.
Second, from the perspective of the teacher-student role, in the traditional classroom, the teacher is the owner and communicator of knowledge, and the student is usually in a position to passively accept knowledge.
In the flipping classroom, the role of the teacher is changed from the "actor" and "sage" who were originally taught on the podium to the "director" of the teaching activities and the "coaching" around the students while the students are passively accepted by the audience from the original podium. "Transformed into active participants in teaching activities. The students have more freedom in the teaching process, but the teachers do not let the students let themselves go. However, under the circumstances that the overall progress has been set, the students can arrange the learning process according to their actual situation. Flipping the classroom will help students to truly achieve student-centered teaching and self-study.
From the point of view of teaching resources again, short and elaborate teaching videos (also known as “micro lessonsâ€) are the most important component of flipping classroom teaching resources.
Instructional videos are usually directed to a specific topic and are maintained at a length of about 10 minutes. Through the media player, functions such as pause and playback can be implemented, facilitating students' taking notes and thinking during the learning process, which is beneficial to students' autonomy. Learn. Watching teaching videos under the class makes it easier to learn. Students don't have to be as nervous and afraid of omissions as in class. In the face of problems, students can also communicate with teachers and peers through the Internet for help. Another advantage of the teaching video is that it is convenient for students to review and consolidate after a period of learning.
Finally, from the point of view of the teaching environment, the flipping classroom integrates the offline classroom with the cyberspace through a comprehensive learning management system (LMS). As a basic platform for implementing flipped classroom teaching, the learning management system can help curriculum teachers effectively organize and present teaching resources, dynamically record student learning process information, and timely understand students' learning conditions and difficulties encountered, and thus be able to make more Targeted coaching; Extending interactive interactions in the classroom to cyberspace, the time and effectiveness of teacher-student interactions will greatly increase. Students relying on the learning management system can easily establish a learning community and collaborate to complete learning tasks.
(III) Research progress and practice cases of flipped classrooms With the deepening of the practice of flipping classroom teaching, research related to flipping classrooms is also increasing. In 2011, based on years of experience in flipping classroom teaching, Jonathan Bergman and Aaron Samss published the monograph "Flip Your Class: Every Student in the Class" (FlipYourClassroom:60 ReachEveryStudentinEveryClassEveryDay). In the book, Jonathan Bergman and Aaron Samss shared their hands-on experiences and theoretical conclusions with the readers through their own personal experiences. The book was recommended by the country.
The current research on flipping classrooms involves different disciplines such as economics, mathematics, and mechanical engineering. Its main themes are focused on teaching design and implementation strategies for flipped classrooms, ideas and general characteristics of flipped classrooms, and comparative studies between flipped classrooms and traditional classrooms. . When researching flipping classrooms, the main object of comparison is the traditional classroom. There are great differences in teacher roles, student roles, teaching organization, classroom content, technology applications, and evaluation methods. In the flipping classroom, the teacher is no longer the only one who teaches the course content, but more becomes the instructor and facilitator of the learning process; the student changes from the passive content recipient to the subject of the learning activity; the teaching organization forms from the classroom “Teaching after class + completing work after class†translates into counseling, answering and discussion, etc. The role of technology is to provide convenient learning resources and interactive tools for self-directed learning and collaborative exploration; evaluation methods are multi-level and multi-dimensional. Most of the existing research results support the preference of flipping classrooms over traditional classrooms, but some studies have shown that flip classrooms do not achieve the desired results. The following shows the effect of flipping the classroom through two positive and negative cases.
Miami University "microeconomics" flipped the classroom. The flipping classroom includes two phases before and after the lesson: Before the lesson, the students must first watch the teaching videos, and then conduct guided homework exercises; during the lesson, the students must quickly complete a small number of tests, and then solve problems by To complete the internalization of knowledge, the final summary and feedback.
Figure shows the "reversal" instructional graphic and points out that there are three key steps in "reversing" teaching: learning before the video, discussing and asking questions; learning while watching videos, finding answers based on questions, and applying and solving problems Learning, in-depth questions to explore.
Zhang Jinlei et al. (2012) constructed a flipped classroom teaching model as shown in Talbert's (2011) flipping classroom structure model based on the connotation of flipped classrooms, constructivist learning theory, and systematic instructional design theory.
The teaching model includes pre-learning and classroom learning. In both processes, information technology and activity learning are two powerful levers created to flip the classroom learning environment. The support of information technology and the smooth development of learning activities ensure the construction and generation of personalized collaborative learning environments.
In the preparation stage of teaching, teachers should complete the teaching design work of flipping the classroom. Teaching design is mainly based on the analysis of teaching objectives, teaching objects (students) and teaching content (teaching), making course content (PPT courseware, teaching videos, test question bank, etc.), designing teaching activities (subject task, grouping mechanism, activity guide) , evaluation of gauges, etc.) and teaching environment (teaching equipment, online platforms, network resources, etc.). The preparation phase of teaching is the cornerstone of flipping classroom teaching and determines the success of subsequent learning.
After all the teaching preparation activities are ready, it will enter the memory understanding stage. The memory comprehension phase occurs under the class. Under the guidance of the teacher, the students initially complete the memory and understanding of the course content by watching video courseware, participating in online courses, retrieving network resources, and conducting self-test exercises. The content of memory mainly includes three types: specific knowledge, including knowledge of terminology and specific facts, also known as conceptual knowledge and factual knowledge; procedural knowledge, that is, knowledge of methods and methods of dealing with specific things; metacognitive knowledge, ie, Knowledge of general principles and abstract concepts in the field of study. Let students master the "buoyancy theorem" as an example. Specific knowledge includes conceptual knowledge - what buoyancy is, how it is produced, and how formulas are derived; factual knowledge - such as measuring buoyancy, requires knowing the volume of liquid to be drained , quality and liquid density knowledge; procedural knowledge for the public will use buoyancy theorem; metacognitive knowledge to determine the use of what kind of memory and understanding methods to memorize and understand the theorem. Memory is the lowest level of cognitive learning. Understanding can generally be accomplished in three forms: translation, interpretation, and inference. For example, transformation is the use of utterances that they find meaningful to organize the expression of the content and knowledge they are imparting; interpretation is to interpret and explain the information exchanged, such as defining the understanding of buoyancy theorem in their own words; the inference is through the current Knowledge to speculate about future conditions. Comprehension is the transcendence of simple memory and represents a higher level of cognitive learning.
At this stage, the students made a preliminary understanding of the buoyancy theorem by means of video and so on.
In the application analysis phase, students apply and analyze the knowledge acquired in the previous stage through self-study activities such as homework exercises, group projects, and reflection summaries. Application refers to the ability to apply learned knowledge to new problem situations, including the application of concepts, rules, methods, laws, and theories. For example, students can understand how buoyancy is generated. Under other conditions being equal, changes in liquid density result in changes in buoyancy; the mass of known objects, the volume of liquids displaced, and the density of liquids, students can use buoyancy formulas to calculate buoyancy . Analysis is the decomposition of complex knowledge in order to clarify the relevant levels of various concepts, or to clarify the relationship between the various concepts expressed. Analysis represents a higher level of knowledge than the application because it understands both the material's content and its structure. For example, when students use buoyancy theorem, it is clear what conditions are necessary to solve the buoyancy problem. When solving buoyancy problems, which formula is most convenient and the student chooses a solution to the buoyancy problem, determine whether it is related to existing The level of understanding is consistent. The application analysis phase completes the internalization of knowledge.
In flipping the classroom, the comprehensive evaluation phase is the end result and is an essential step. The comprehensive evaluation stage is the consideration of the students' memory understanding stage and the application analysis stage. From this, the deficiency of the teaching preparation stage can also be found. At this stage, students talk about themselves, learn reports, self-assessments, and small “reversal†teaching circles flip classroom teaching. In flipping classroom teaching, students are the main body of learning activities, and teachers are the organizers and participants of learning activities. And promoters. In the existing model of flipping classrooms, students’ learning activities are generally used as the main line and viewing of teaching videos as the starting point. This fully reflects the idea of ​​using learner-centered learning and the characteristics of flipping classroom teaching and learning “flipâ€. . However, flipping the classroom is a bilateral interaction process consisting of teacher's teaching and student's learning, overemphasizing "learning" and ignoring "teaching."
It is easy to go from one extreme to the other. Inspired by the concept of “Tai Chi School†proposed by Sang Xinmin et al. (2012), this article integrates the concept of flipping classrooms, the Tai Chi ideas in traditional Chinese culture, and Benjamin Bloom’s cognitive goal teaching classification theory. Modeling and building a Tai Chi-style flip classroom model, as shown.
Activities such as peer evaluations communicate and evaluate learning processes and learning outcomes. The purpose of synthesis is to combine elements and components into a whole, such as combining the various learning and thinking activities that take place under the class into a whole, and presenting them with content-unique reports or challenging tasks. Project operations plan or outline a set of abstract relationships. It emphasizes creativity and needs new models or structures. For example, during the learning process of the buoyancy theorem, students analyze and summarize the cases related to buoyancy and buoyancy, and apply what they have learned to solve problems in real situations. Evaluation here refers to the ability to make value judgments on materials, including making value judgments based on internal standards (such as organization) or external standards (such as appropriateness of purpose). This is the highest level of cognitive learning results. In addition to this, in the comprehensive evaluation stage, the students in the process of presenting the individual's understanding of knowledge, the teachers and other students will evaluate them according to the individual's understanding of the knowledge, so as to gradually perfect the process of personal knowledge internalization in constant communication and collision. .
Finally, it should be noted that although the flipping classroom does not necessarily operate in an information-based environment, the information-based teaching environment provides a wealth of teaching resources and a full range of interactive forms for flipping the classroom. It can fully mobilize students more than the traditional teaching environment. Learning enthusiasm and initiative. As students shift from digital migration to digital aborigines, in addition to considering the campus resources in the school environment, flipping classrooms must consider integrating cloud resources in a social environment.
Concluding Remarks Regardless of whether it is flipping a classroom or a traditional classroom, the basic process is the process of teaching interactions around the problem context. The Taiji ring model proposed in this paper can well reflect the relationship of teaching, learning, and learning in a harmonious, harmonious, and mutual transformation, and provides a theory for the practice of overturning classrooms in the context of Chinese local culture. However, unfortunately, this article does not introduce practical applications of the Tai Chi-style flip classroom model. In the following work, we will follow the design and research to gradually improve the thinking, put the Tai Chi-style model into practice, see how effective it is, and continue to improve based on practical feedback to form a more reliable and effective model. Looking forward to the practice of amendments, we can propose a more complete flip classroom model and academic sharing.
Flap Disc
Flap disc, commonly known as flat emery cloth wheels, emery discs, flower impellers or elastic grinding discs, are a large variety of coated abrasive conversion products, which press the cut coated abrasive sheets one by one. It is formed by sticking adhesive to the back cover plate along the circumference. The flap disc are called strong elastic grinding discs. They are made of calcined emery cloth, which uses mesh, nylon, plastic, steel paper and other materials as the base. Attached abrasive tools, evenly distributed in a fan shape to ensure the best grinding effect. The particle size is 36#-320#, 60# and 80# are the most common, and the outer diameter is 4"-7" installed on the angle grinder. Angle grinders are mainly installed on hand-held Power Tools to polish and polish welds, burrs, chamfers, surface rust removal, and surface polishing of various metal and non-metal parts.
The flat emery cloth wheel (flap wheel) is formed by sticking multiple emery cloth sheets on the tray in a fan-shaped superimposed arrangement, and the bonding angle between each emery cloth and the tray plane is 10°-30°. The emery cloth arrangement of the utility model can make When the abrasive cloth wheel grinds and polishes the workpiece to be processed, the cutting angle is optimized to ensure that the base material of the abrasive cloth wheel and the grinding are consumed simultaneously, which obviously improves the overall wear resistance and grinding efficiency of the flat abrasive cloth wheel, and prolongs the service life of the abrasive cloth wheel. Grind the surface of metallic and non-metallic materials.
product advantages:
Compared with the resin grinding wheel for fixed abrasives, it has the advantages of polishing and polishing at one time, shortening the operation time, saving the grinding cost, high efficiency, good heat dissipation, high grinding efficiency, reducing operator fatigue, increasing machine life, etc. It has strong elasticity, High tensile and bending strength and good grinding effect. The grinding speed is fast, the effect is good, and the noise during grinding is low. It is suitable for various industries or fields of manufacturing such as major metal parts factories and machinery factories. Good weather resistance, salt spray resistance and heat resistance, suitable for use in different regions.
Scope of application:
It is suitable for polishing of stainless steel, metal, metallurgy, automobile, wood, marble and other industries. It is especially suitable for the processing of stainless steel and can replace the resin-shaped grinding wheel. It has strong elasticity, high tensile and bending strength, good self-sharpening, high grinding rate, and low noise. It is suitable for welding seams in the box. Polishing of the edges.
There are different classifications of louvers according to different angles. The following are two common classifications:
According to the appearance: T27 VS T29
Flap disc generally have two shapes, curved and flat.
The flap disc type is also called the T27 type, and the curved type generally refers to the T29 type.
The flap disc type (T27) has a flat surface. It is mainly used to polish the flat surface and the external edges and corners. The flap disc and the workpiece are angled during work, which can complete the grinding and polishing at one time, reducing the work flow.
The curved surface of the curved louver (T29) has an upward arc, which makes the T29 flap disc have a better cutting ability on the plane. When working, the T29 type grinding wheel forms an angle of 15° to 25° with the grinding surface, which is mainly used to deal with the grinding of contours and edges. When there are higher requirements for speed and cutting ability, T29 flap disc is undoubtedly the best choice.
The related abrasive products we can supply is Flap Disc Adhesive, Bonded Abrasives , and Abrasive Machine such as Flap Disc Making Machine,Abrasive Belt Making Machine, Flap Wheel Machine , Polishing Machine ,Sanding Disc Machine, if you have any needs about abrasive tools, please kindly feel free to contact us.
According to the type of abrasive particles: ceramic alumina VS zirconium corundum VS alumina
According to the type of abrasive selected, the flap disc can be divided into three types: ceramic alumina, zirconium corundum and alumina.
Because ceramic alumina itself has many crystals, it has good self-sharpening, relatively neat edges, good heat dissipation, and long service life. Therefore, ceramic alumina louvers are mainly used for the grinding of stainless steel, aluminum and other hard metals.
Zirconium corundum itself is a polycrystalline crystal, with fast cutting speed, good self-sharpening, and strong resistance to high pressure and high temperature. Therefore, zirconium corundum louver blades have strong cutting ability and long service life.
Alumina: single crystal, the cutting ability begins to decline at the beginning of grinding, and the abrasive grains are not easy to break, so the alumina flap disc is suitable for the processing of common metals.
Flap Disc,Flap Disc Machine,flap disk 4.5,Polishing Flap Disc,Sandpaper Flap Wheel
Zhengzhou Jiading Abrasive Manufacturing Co.,Ltd , https://www.jd-abrasives.com