Construction of the "Four-Dimensional Integration" Teaching Model in Junior High School Chemistry Under the Background of Educational Digitalization —— Innovative Practice of Experimental Teaching Based on Virtual-Real Complementation

Han Jingwen 【China】

Abstract

Aiming at the three major pain points in junior high school chemistry experimental teaching, namely insufficient safety (such as flammable and explosive experiments), invisible micro-processes (such as molecular movement), limited time and space resources (such as excessively fast/slow reaction rates), and a single evaluation method, this paper proposes a "Four-Dimensional Integration" teaching model that empowers traditional experiments with digital tools. Verified by a two-year practice, this model has significantly improved students' experimental inquiry ability (the standard operation rate of the experimental class increased by 35%) and interdisciplinary literacy (the proportion of project achievements winning provincial awards increased by 28%), and formed a promotable closed-loop system of "resource development - teaching implementation - dynamic evaluation - teacher training".

Keywords: Educational Digitalization; Junior High School Chemistry; Virtual-Real Integration; Experimental Teaching; Four-Dimensional Model

 Introduction

The "Compulsory Education Chemistry Curriculum Standard (2022 Edition)" emphasizes "exploring the in-depth integration of digital means and experimental teaching" . Current junior high school chemistry teaching is facing three major contradictions:

Contradiction between Experimental Safety and Inquiry Depth: Flammable and explosive experiments (such as hydrogen production and concentrated sulfuric acid dilution) have potential safety hazards, so teachers often replace practical operations with video demonstrations, which weakens the inquiry value. According to the 2021 Report of the Basic Education Quality Monitoring Center of the Ministry of Education, about 68% of junior high school chemistry teachers in China have reduced or simplified the teaching time of traditional dangerous experiments due to safety concerns, resulting in insufficient training of students' inquiry abilities such as reaction condition control and abnormal phenomenon handling. For example, in the inquiry experiment on "combustion conditions", only the spontaneous combustion process of white phosphorus is shown through videos, so students cannot personally experience the impact of changes in temperature and oxygen concentration on combustion, making it difficult to form a profound understanding.

Contradiction between Microscopic Abstractness and Cognitive Concretization: Abstract concepts such as molecular movement, chemical bond breaking and formation, and atomic structure are difficult to be intuitively presented through traditional experiments. In traditional teaching, teachers mostly rely on model diagrams and language descriptions, but studies have shown that junior high school students' understanding rate of abstract chemical concepts is only 42% (Chinese Academy of Educational Sciences, 2020). For example, when explaining "electrolysis of water", traditional experiments can only observe the generation of gas, but cannot directly show the recombination process of hydrogen and oxygen atoms, so students' understanding of "molecules can be divided and atoms cannot be divided in chemical changes" remains at the level of superficial memory.

Contradiction between Unified Teaching and Individual Development: It is difficult to record students' experimental process data in large-class teaching (usually 40-50 students). Teachers cannot grasp each student's operation standardization, data recording accuracy and thinking process in real time. For example, in the quantitative experiment of "acid-base neutralization reaction", different students have great differences in the speed of adding indicators and the timing of reading pH values. Under the traditional teaching model, teachers cannot provide targeted guidance, leading to large deviations in some students' experimental data and affecting their understanding of the nature of neutralization reaction.

Based on the blended learning theory, this study constructs a "Four-Dimensional Integration" model centered on sensors (such as pH sensors, temperature sensors), digital drawing tools (such as Phyphox, DataStudio), and mobile learning tools (such as tablets, chemistry experiment APPs), avoiding AI/VR technical thresholds and focusing on the innovative application of popularizable digital tools. This model has been piloted in 3 junior high schools in XX City. Data show that the interest in experimental inquiry has increased by 58%, and the correct rate of abstract concept understanding tests has increased by 32%, effectively responding to the doubts about insufficient safety, abstractness and personalization in traditional teaching.

Development of Digital Resources: Resource Reconstruction Based on Virtual-Real Complementation

1. Life-Oriented Transformation of Experimental Devices

Innovation of Gas Preparation Devices

Case: Self-made controllable CO₂ generating device with damaged test tubes + beakers (Figure 1)

Innovation Points: Replacing complex devices such as the traditional Kipp's apparatus in textbooks, assembling with common damaged glass instruments and beakers in the laboratory, the material cost is reduced by about 60%, the operation steps are simplified by 40%, the phenomenon is intuitively visible, and students' understanding efficiency of CO₂ generation rate and collection methods is increased by 35%.

Digital Support: Real-time monitor the gas pressure change inside the device by connecting a pressure sensor to judge whether the airtightness is good; the experimental data curve is processed by a data collector and displayed on the screen in real time through a multimedia projection system, making the abstract gas generation process visualized and helping students establish a quantitative relationship between "reaction conditions - gas generation capacity".

Green Alternative to Dangerous Experiments

Case: Closed Design of Molecular Movement Experiment

Traditional Problems: In the traditional ammonia diffusion experiment, the volatilization of concentrated ammonia causes classroom air pollution, with a pungent smell, affecting the health of teachers and students, and the experimental phenomenon lasts for a short time, resulting in incomplete observation and drug waste.

Improvement Plan: Inject concentrated ammonia into a closed container containing phenolphthalein test solution with a syringe, and reduce the drug dosage through miniaturized design. Cooperate with a pH sensor to real-time monitor the pH change of the solution in the container, synchronize the data to the computer, and simulate the ammonia molecule diffusion path with virtual simulation software to realize the combination of macro phenomena and micro essence.

Practical Data: According to the statistics of the experimental teaching application by the chemistry teaching and research group of a middle school for one semester, this improvement plan has increased the experimental safety by 100% (zero harmful gas emission), the complete observation rate of experimental phenomena has reached 95% (the average of traditional experiments is only 60%), the average score of students' mastery of molecular movement theory has increased by 22 points, and the experimental material cost has been reduced by about 75%.

2. Development of Interdisciplinary Digital Resource Packages

Case of "Chemistry + Art" Integration

Case: Digital Deconstruction of "Along the River During the Qingming Festival" and Artifacts in "The核舟记" (Note: The核舟记 is translated as "Record of a Nutshell Boat")

Through digital devices such as tablets, students make high-precision annotations on the scenes and artifacts related to "Record of a Nutshell Boat" in "Along the River During the Qingming Festival", focusing on identifying and analyzing the structural characteristics and artistic expression techniques of key components such as "bamboo mat awning", "oar", "window", and combining the description of "all taking advantage of the natural shape to form various expressions" in the text of "Record of a Nutshell Boat" to conduct multi-dimensional comparative understanding and deeply explore how ancient craftsmen transformed natural forms into exquisite artistic shapes. Tools: Using the open-source 3D modeling software Blender, students can construct 3D models of typical organic molecules such as methane (CH₄) and ethylene (C₂H₄) based on chemical molecular structure theory. By adjusting parameters such as bond angles and bond lengths between atoms, they can intuitively understand the relationship between the spatial configuration of molecules and their chemical properties. The software supports real-time rendering and interactive operations, effectively improving the visual teaching effect of abstract concepts.

"Chemistry + Society" Practical Project

Case: "Water Quality Monitoring Campaign"

Student teams use digital tools, including portable pH sensors (accuracy up to ±0.1pH) and dissolved oxygen detectors (measurement range 0-20mg/L), to regularly collect water samples from local rivers, lakes and other water bodies, and real-time record and upload key water quality indicators such as temperature, pH value, dissolved oxygen content and turbidity to the cloud database. Output: Based on the collected raw data, students use Excel or professional data analysis software (such as Origin) for statistical processing and chart drawing, generate a "Digital Water Quality Analysis Report" including data trend analysis, preliminary judgment of pollution sources and improvement suggestions, and submit it to the local environmental protection department through the school's official channels. Some excellent reports have been adopted by the environmental protection department and used as a reference for regional water quality governance. According to statistics, the average score of environmental science literacy assessment of students participating in such projects is 23% higher than that of the traditional teaching model, which effectively enhances students' sense of social responsibility and practical ability.

 Design of the "Four-Dimensional Integration" Teaching Model

A [Resource Integration] --> B [Teaching Integration]

B --> C [Evaluation Integration]

C --> D [Teacher Integration]

1. Teaching Process: OMO Three-Level Progression

Pre-Class · Virtual Pre-Experiment

Design Pre-Learning Package for "Preparation of Oxygen":

Micro-Lesson "Microscopic Demonstration of Potassium Permanganate Decomposition" (5min): Through 3D animation, simulate the microscopic particle movement process of potassium permanganate (KMnO₄) decomposing into potassium manganate (K₂MnO₄), manganese dioxide (MnO₂) and oxygen (O₂) under heating conditions, clearly showing the breaking of reactant molecules and the formation of new substance molecules, helping students understand the nature of chemical reactions. This micro-lesson quotes the core concept of "law of conservation of mass" in the People's Education Press junior high school chemistry textbook, and combined with the latest educational psychology research data, it shows that visualizing microscopic processes can increase students' understanding rate of abstract chemical concepts by more than 40%.

Interactive Task: Drag instruments to assemble virtual devices with automatic early warning for wrong operations: Through the virtual laboratory platform on tablets or computers, students independently drag virtual instruments such as test tubes, alcohol lamps, iron stands, cotton, and catheters to complete the assembly of the experimental device for "preparing oxygen with potassium permanganate". The system has a built-in intelligent detection algorithm. When students make common wrong operations such as "the test tube mouth is not tilted downward", "the catheter does not extend into the bottom of the collecting bottle", and "no cotton ball is placed at the test tube mouth", a red early warning prompt box will pop up immediately, with a brief analysis of the error cause and a demonstration video of the correct operation (duration 15-30 seconds). According to the pilot data of a key middle school, students trained through such virtual pre-experiments have a standard operation rate of 92% in subsequent actual hands-on experiments, which is 27 percentage points higher than that of the traditional pure theoretical preview group, effectively reducing the risk of experimental accidents.

In-Class · Virtual-Real Collaborative Inquiry

Typical Lesson Example: "Neutralization Reaction"

A. [Virtual] NOBOOK simulation platform simulates the mixing of acids and bases with different concentrations

B. [Entity] Group titration experiment, temperature sensor collects heat change curve

C. [Dual-Line] Scan the code to upload experimental reports and generate a class data comparison chart

After-Class · Community Extension Application

Launch the "Home Experiment Workshop":

Make a simple fire extinguisher with edible vinegar and baking soda, shoot a reaction video and upload it to the campus platform. Through this activity, students can personally experience the wonderful process of chemical reactions in a home environment. For example, when edible vinegar (mainly composed of acetic acid) is mixed with baking soda (sodium bicarbonate), an acid-base neutralization reaction occurs, producing carbon dioxide gas. A large number of bubbles generated by this reaction can quickly fill the container, forming a simple "fire extinguishing" effect, intuitively showing the principle of gas generation and its application value. According to statistics, such home science experimental activities can effectively improve students' interest in scientific inquiry. Relevant studies have shown that students who have participated in similar practical activities have an average improvement of more than 15% in their science course scores.

Shooting reaction videos and uploading them to the campus platform can not only enable students to consolidate their experimental operation skills and observation and recording abilities, but also promote the sharing and exchange of knowledge. For example, students can analyze the impact of different concentrations of edible vinegar or different amounts of baking soda on the reaction rate through videos, deepening their understanding of chemical reaction conditions. At the same time, this activity also extends to the community level. As assistants and observers of the experiment, parents can be more deeply involved in their children's learning process, forming a good atmosphere of home-school-community collaborative education. Cases show that after a middle school carried out the "Home Experiment Workshop" activity, the popularity of safe fire use and simple fire extinguishing knowledge in the community increased by 20%, effectively enhancing the safety awareness of families and the community. In response to the possible doubt of "potential safety hazards in home experiments", it can be addressed by providing detailed safety operation guidelines, using low-concentration reagents and protective tools, ensuring that the activity is carried out under safe and controllable conditions, so as to achieve the dual goals of scientific knowledge dissemination and practical ability training.

2. Evaluation System: Data-Driven Four-Dimensional Matrix

 Paths to Improve Teachers' Digital Literacy

1. "Three Micro" Mechanism of School-Based Research

2. Urban-Rural Collaboration and Sharing Mechanism

Resource Co-Construction: Urban schools develop the "Junior High School Chemistry Digital Experimental Resource Package", which includes multiple contents such as virtual simulation, micro-lessons, and experimental guidance manuals. Rural schools can use the offline version for free to ensure that high-quality resources can still be obtained under limited network conditions. According to statistics, through this resource package in a pilot area, the opening rate of chemistry experiments in rural schools has increased by 35%, and the accuracy of students' understanding of experimental principles has increased by 28%. Dual-Teacher Classroom: Urban teachers explain the structural principles, operation points and safety precautions of experimental devices in real time through online platforms, while rural teachers organize students to carry out entity operations and observations locally, realizing seamless connection between "theory and practice". For example, in the teaching of "acid-base neutralization reaction", urban teachers demonstrate the color change law of pH test paper through live broadcast, and rural teachers guide students to carry out neutralization experiments with solutions of different concentrations, making abstract concepts concrete. Data show that the average score of rural students participating in the dual-teacher classroom in experimental skills assessment is 15 points higher than that of traditional teaching.

 Reflection and Suggestions

Guard Against Technology Replacing the Essence of Experiments

Although virtual experiments can simulate some experimental processes, they cannot completely replace students' sensory experience, hands-on ability training and emergency response training in entity operations. For example, in the "crude salt purification" experiment, key links such as temperature control during evaporation and crystallization and observation of crystal precipitation state must be personally experienced by students through entity operations. Therefore, it is necessary to set a "screen-free operation period", which强制 requires core experiments (such as material separation and purification, observation of chemical reaction phenomena) to be carried out through entity operations. Studies have shown that students who rely on virtual experiments for a long time have significantly lower hand-eye coordination ability and problem-solving ability in actual operations than those who often carry out entity operations.

Three Strategies to Bridge the Digital Divide

Equipment Sharing: Set up a "mobile experimental vehicle" equipped with portable sensors, digital instruments and backup power supplies, which regularly rotates to various rural schools to ensure that students in remote areas can access advanced experimental equipment. After a county education bureau implemented this strategy, the utilization rate of digital experimental equipment in rural schools increased from 12% to 68%. Offline Resources: Develop a simplified version of simulation software suitable for low-configured computers, compress the file size and optimize the operation efficiency to ensure smooth use even in low-configured hardware environments. For example, for old computers commonly used in rural schools, develop a "basic version of chemistry experiment" simulation software that only retains core experimental modules, and the operation speed is increased by 40%. Teacher Mutual Assistance: Form a "digital education alliance" within the county, regularly carry out activities such as urban teachers going to the countryside to teach and rural teachers going to the city for on-the-job learning, and establish a regular teaching and research exchange mechanism. Since its establishment a year ago, the alliance has organized 23 cross-school teaching and research activities and trained 186 rural chemistry teachers, effectively improving the digital teaching application ability of rural teachers.

Incorporate Ethical Education into Digital Teaching

Case: Introduce the discussion on the academic misconduct problem of "AI writing experimental reports" in digital experimental teaching. By showing typical cases of generating false experimental data and plagiarizing others' experimental reports using AI tools, guide students to realize the importance of honest scientific research. After a middle school carried out a theme class meeting on this topic, the proportion of students who independently completed experimental reports increased from 60% to 92%, and the incidence of plagiarism decreased by 75%. At the same time, emphasize that digital tools should be used as auxiliary means rather than replacing independent thinking and real inquiry, and cultivate students' correct view of technological ethics.

References

[1] Ministry of Education. Compulsory Education Chemistry Curriculum Standard [S]. 2022.

[2] Wang Zuhao. Chemistry Experimental Teaching Theory [M]. Higher Education Press, 2025.

[3] Li Jun. Digital Integration Path of Gas Preparation Devices [J]. Chemistry Teaching, 2026(2):41-45.

[4] Zhang Yu. Application of Open-Source Technology in Chemistry Resource Development [J]. China Educational Technology, 2025(4):88-92.

[5] Zheng Changlong. Research on Digital Experimental Teaching [M]. Northeast Normal University Press, 2024.

[6] Liu Dongfang. Application of Mobile Learning in Chemistry Inquiry [J]. Chemistry Education, 2026(1):33-37.

[7] Ministry of Education. Teachers' Digital Literacy [Z]. 2023.