Reconstructing High School Chemistry Laboratory Teaching Oriented by Core Competencies: An Exploration of a-dimensional Linkage School-based Model

Han Xiaoqi 【China】

Abstract:

In response to the three major pain points that have long existed in high school laboratory teaching, namely, high reliance on equipment (51% idle rate of digital equipment ※), superficial student participation (83% staying at the level of operational im ※), and inter-school differences between urban and rural areas (imbalance in resource allocation), this study pioneered a four-dimensional linkage model of 'al Hierarchy—Life Immersion—Open Inquiry—Digital Empowerment'. Through a three-year tracking practice in the same school and grade (2019 4 parallel classes, n=192), it was verified that this model significantly enhanced experimental innovation ability (58.7% increase in the experimental group compared to control group), scientific argumentation ability (31.2% increase in the proportion of students reaching the extended abstract level in SOLO classification), and subject identity (9.3% retention rate of continuous elective), providing a replicable model for the reform of school-based laboratory teaching. Specifically, goal hierarchy emphasizes setting personalized goals according to' different learning levels, life immersion stimulates students' interest and understanding by introducing chemical phenomena from daily life into the classroom, open inquiry encourages students to design their own experimental plans explore independently, and digital empowerment uses modern information technology to assist teaching, improving teaching efficiency and effectiveness. These measures work together not only to improve students' experimental skills and scientific literacy but to enhance their love and identity with the chemistry subject, providing effective references for teaching reform in other schools.

Keywords: Core Competencies  Hierarchical Experiments Lifeoriented Situations  School-based Curriculum  

Formative Evaluation

1. Deep Dive into the Problem: Analysis of School-based Difficulties in Experimental Teaching

1.1 Bottleneck in Experimental Implementation under Resource Constraints

Double Shortage of Equipment and Class Time

The daily usage rate of our school's laboratory is only 3.4% (account book of 2020), and high-end equipment (such as UV-Vis spectrophotometer) is used ≤3 times year, resulting in extremely low utilization of equipment in experimental teaching and failing to meet students' needs for operating advanced instruments. Moreover, due to insufficient funds for equipment maintenance and renewal, equipment has been idle for a long time, further exacerbating the waste of resources.

The compulsory experiments require 42 class hours of theory, but only 28 class are actually completed (a compression rate of 33.3%), which not only affects the cultivation of students' experimental operation skills but also limits their in-depth understanding the principles of the experiment. The severe shortage of experimental class hours makes it impossible to carry out many complex experiments, affecting the overall quality of teaching.

1.2 Struct Imbalance in Students' Competence Development

(a) Distribution of Thinking Levels (Based on SOLO Taxonomy Assessment)

In the process of students' competence, structural imbalance is a common problem. This imbalance is mainly reflected in the distribution of thinking levels among different students, and SOLO taxonomy assessment (Structure of the Observed Learningcome) is an effective assessment tool.

SOLO taxonomy assessment divides students' thinking levels into five levels: pre-structural level, single-point structural level,-point structural level, relational structural level, and abstract extended structural level. Through these levels, it is possible to clearly understand the depth and breadth of students' thinking in different subjects tasks.

Students at the pre-structural level typically fail to understand the task requirements, with their responses being chaotic and lacking logic. Those at single-point structural level can grasp a key point but fail to consider the issue comprehensively. Students at the multi-point structural level can identify multiple relevant points, but these lack connection. Students at the relational structural level can not only identify multiple relevant points but also organically link them to form a more complete understanding. Students at the abstract-expanding level can transcend concrete examples, engage in abstract thinking, and propose new insights and theories.

Through SOLO taxonomy assessment, teachers can discover the strengths and weaknesses of students at levels of thinking, thus designing targeted teaching activities to promote the overall development of students' thinking abilities. For example, for students at the pre-structural level, teachers can help establish basic understanding by providing clear task guidance and specific examples; for students at the relational structural level, teachers can design tasks that require the comprehensive application of knowledge to further enhance their and breadth of thinking.

In summary, through SOLO taxonomy assessment, teachers can better understand and address the structural imbalance in students' ability development, provide personalized learning support for student, and promote their overall improvement in thinking abilities.

1.3  Disciplinary Value Identification Crisis

In the current educational environment, the disciplinary value identification crisis has become an increasingly issue. This phenomenon is mainly manifested in students' lack of deep understanding and identification of the importance, practicality, and future development potential of certain disciplines. This crisis not only affects' academic performance but may also have a profound impact on their career choices and lifelong development.

Firstly, the disciplinary value identification crisis stems from societal and family biases against disciplines For example, some parents and students may believe that humanities subjects are less important than science subjects, leading to a lack of motivation and confidence among arts students in their learning process., excessive promotion or neglect of certain subjects by the media and social opinion also exacerbates this issue.

Secondly, the assessment mechanisms within the school education system are also an important contributing to the disciplinary value identification crisis. The traditional examination system often emphasizes the memorization and recall of knowledge, while neglecting the cultivation of students' comprehensive abilities. This makes it for students to see their progress and achievements in non-examination subjects, thereby weakening their interest and sense of identity in those disciplines.

To address this problem, it is to start from multiple aspects. Firstly, policymakers should push for the reform of the education evaluation system, increasing the assessment of students' comprehensive quality and innovative abilities. Secondly, teachers focus on inspiring students' interest in learning during the teaching process, allowing them to experience the practical application value of disciplines through real-life cases and project-based learning. Finally, and society should also change their traditional views on disciplines, giving students more support and encouragement to help them establish the correct disciplinary values.

Motivation Survey (n=192)

Distribution of Learning Motivation in Experimental Class:

"To cope with exams": 46.2%; "To explore interests": 29.1%; "To the requirements of further education": 24.7%

2. Construction of the Four-dimensional Linkage Model

(a) Objectives Hierarchy: A Threelevel Capability Advancement Framework

Hierarchical Design of School-based (Taking the "Principles of Chemical Reactions" module as an example

(b) Life Immersion: Real Situation Chain Development

Local Resource Transformation

Case: Utilizing the process of a local winery to analyze redox reactions (students sample and determine SO₂ residue). By visiting the site and communicating with the winemakers, students can intuitively understand the application of chemical reactions in actual production. For example, during the fermentation of wine, yeast converts glucose into alcohol and carbon dioxide, while also producing a small amount sulfur dioxide (SO₂), which is used to prevent the oxidation of wine and microbial contamination. Students, by collecting samples and using titration to determine the SO₂, not only master chemical analysis techniques but also understand their importance in the food industry.

Data: The concept transfer score of the life-oriented experimental group (4.325) was significantly higher than that of the traditional group (2.87/5). This shows that students' understanding and application ability have been significantly improved by combining classroom with concrete situations in real life. This teaching method not only enhances students' interest in learning but also improves their ability to solve practical problems.

(c) Open Inquiry Dual-Drive Mechanism

 Problem Open Generation

Extending from "Laboratory Preparation of Chlorine Gas" to "Safety Assessment of Residual Chlor in Tap Water".

In the laboratory, chlorine gas can be prepared through the reaction of manganese dioxide with concentrated hydrochloric acid, involving the principles and operational of chemical reactions. Specifically, the reaction equation is MnO2   4HCl (concentrated) → MnCl2   Cl2↑   2H2O The generated chlorine gas has strong oxidizing properties and can be used for disinfection, bleaching, and other purposes.

However, in practical applications, the use chlorine gas needs to be strictly controlled, especially in the treatment of tap water. To ensure the safety of drinking water, water companies usually add a proper amount of chlorine gas sodium hypochlorite to the water to kill pathogenic microorganisms in the water. Although this method is effective, it also raises concerns about the residue of residual chlorine its impact on human health.

Therefore, starting from the laboratory preparation of chlorine gas, we can further explore the safety assessment of residual chlorine in tap water. This includes the concentration of residual chlorine in water samples, analyzing its potential risks to human health, and studying how to control the content of residual chlorine within a safe range while ensuring theinfection effect. In addition, other alternative disinfection methods, such as ultraviolet disinfection and ozone disinfection, can also be explored to reduce the reliance onine gas and thereby improve the safety and taste of drinking water.

(d) Digital Empowerment: Low-cost Technological Reform Path

Smartphone Sensor ApplicationsCase: Determining Equilibrium Constants with Phyphox Colorimeter Sensor (Error <4.2% compared to traditional colorimetry), by utilizing the highprecision sensors built into smartphones, it is possible to achieve precise measurements of the equilibrium constants of chemical reactions. This method not only reduces the cost of experiments but also improves the accuracy reliability of the data. In addition, the Phyphox application provides an intuitive user interface and powerful data analysis functions, making it easier for students and researchers to conduct experiments and data.

Over the past three years, a total of 12 digital experimental packages have been developed and integrated into the school curriculum, covering various disciplines such as physics, chemistry biology, etc., aiming to enhance teaching effectiveness and research efficiency through digital means. Each experimental package has been carefully designed and tested multiple times to ensure its feasibility and effectiveness in practical. These digital experimental packages not only enrich teaching resources but also provide students with more hands-on opportunities, helping to cultivate their scientific inquiry and innovative thinking skills.

3. School-based Practice Cases

Traditional Experiment Reconstruction: "Galvanic Cell" Module

Hierarchical Implementation Path

Basic Layer: Zinc-Cper Galvanic Cell Textbook Experiment

At the basic layer, students will gain an understanding of the basic principles of galvanic cells through the classic zinc-copper galic cell experiment. This experiment usually involves using zinc and copper plates as electrodes, connecting the two half-cells with a salt bridge or electrolyte solution, and observing the generation of. Through this experiment, students can understand the basic concepts of oxidation-reduction reactions, as well as the direction of electron flow and the energy conversion process.

Advanced Layer Optimization of Output Power of Fruit Batteries (Exploring the Impact of Electrode Spacing/Citric Acid Concentration)

At the advanced layer, students further explore how to optimize the output power of fruit batteries. Specifically, they can study the effect of changing the distance between electrodes on the performance of the battery. For example, increasing distance between electrodes may lead to increased resistance, thereby reducing the current output. In addition, students can also explore the impact of citric acid concentration in different types of fruits on the of the battery. By adjusting these variables, students can gain a deeper understanding of the key factors in electrochemical reactions and learn how to analyze and optimize through experimental data.

novation Layer: Designing a "Methane Fuel Cell" Miniaturized Model ※

At the innovation layer, students will be challenged to design a miniaturized fuel cell model. This task not only requires students to master the working principles of methane fuel cells but also encourages them to be innovative in material selection, structure design, and system integration A methane fuel cell is a device that uses the electrochemical reaction of methane with oxygen to directly generate electricity, featuring high efficiency and cleanliness. Students need to consider how to achieve gas delivery and reaction control in a miniaturized device while ensuring the stability and reliability of the system. Through this project, students can not only enhance their engineering design capabilities but also comprehensive qualities for solving complex problems.

4、 Three year tracking effectiveness analysis

(a) Quantitative data comparison (experimental group vs control group)，n=96/96）

（b）Deep mining of qualitative evidence

①Case Study of Cognitive Progression:

In a case study of cognitive progression, students conducted detailed efficiency measurements on various common fruits, such as apples, bananas, and oranges, using sophisticated experimental equipment. They discovered that the migration rate of electrolyte ions within the fruits affects the output power of the battery, a phenomenon that far surpasses the importance of electrode material activity emphasized in traditional textbooks. During the experiment, students used high-precision ammet and voltmeters to record the electrochemical reaction data of different fruits under different environmental conditions. These data not only revealed the critical role of electrolyte ions in fruit batteries but also new perspectives and ideas for future energy research.

②Career Aspiration Tracking

The proportion of students in the experimental group choosing chemistry-related majors was 41.%, an increase of 81.5% compared to the control group (22.7%). The students in the experimental group's strong interest in and indepth study of chemistry allowed them to continuously explore unknown territories in the laboratory, with every detail from molecular structure to chemical reactions stimulating their curiosity. Although there were also some students in control group who chose chemistry majors, the overall proportion was significantly lower, showing the experimental group's significant advantage in career planning and subject selection.

5. Suggestions forized Implementation

(a) Resource Optimization Path

Dynamic Equipment Management

By introducing advanced equipment management systems, real-time monitoring and maintenance of laboratory equipment can be achieved, ensuring efficient of equipment. For example, by using Internet of Things technology, the usage status and location of equipment can be tracked in real-time, and equipment faults can be discovered and resolved, improving the availability and service life of the equipment.

Establishment of "Experimental Equipment Floating Station" (Increasing Sharing Rate to 76.8%)

Est a school-wide experimental equipment floating station, encouraging students and teachers to share experimental equipment and reduce duplicate purchases and waste. Through online platform booking and offline pick-up and return it is convenient for teachers and students to obtain the necessary equipment. At the same time, regular sharing meetings are held to exchange experiences and insights on equipment usage, further improving the sharing.

Family Experiment Kit Development

Design and develop a series of simple and easy-to-operate family experiment kits for students to conduct scientific exploration at home. These experiment kits basic experimental equipment and detailed experimental guide manuals, suitable for students of different ages to use. For example, a simple chemical experiment kit designed for elementary school students contains safe and nontoxic reagents and simple experimental steps, cultivating their scientific interest and hands-on ability.

Case: Miniature Colorimeter (Cost < 20 Yuan) Heavy Metal Detection in Water

Develop low-cost miniature colorimeters for detecting heavy metal content in water. This type of colorimeter is compact, easy to operate, and suitable for in school laboratories and homes. Through the color change of the colorimeter, it can quickly determine whether the water quality is contaminated by heavy metals, with high accuracy and sensitivity. cost of this device is kept within 20 yuan, allowing more schools and homes to afford it, thereby raising public awareness of water quality safety.

(b) Teacher Collaborative Mechanism

Interdisciplinary teaching and research group construction: Joint lesson preparation every month (hemistry-Biology-Physics teachers) to solve real problems.

A[Wastewater purification project] --> B(Chemistry teacher: Coag reaction)

A --> C(Biology teacher: Microbial culture)

A --> D(Physics teacher: Fluid design)

(c) Evaluation Upgrade

School-based experimental capability certification

To better assess students' experimental capabilities and practical operation levels, the school decided to upgrade the existing evaluation system. The new evaluation will place greater emphasis on students' performance and innovative abilities during the experimental process, rather than just the experimental results.

Firstly, the school-based experimental capability certification will include-dimensional assessments, such as experimental design, data collection and analysis, problem-solving skills, and teamwork. Each dimension will have specific scoring criteria and detailed evaluation rules to the fairness and scientific nature of the assessment.

Secondly, the evaluation system will also introduce a variety of assessment methods, such as project presentations, oral reports, experimental record reviews and peer evaluations. These methods can not only reflect students' experimental capabilities comprehensively but also cultivate their communication skills and critical thinking.

In addition, to improve the transparency of assessment and the effectiveness of feedback, the school will establish an online platform where students can view their assessment results and receive detailed feedback. This will help students understand their strengths and weaknesses, making targeted improvements and enhancements.

Finally, the school-based experimental capability certification will be regularly updated and perfected to adapt to new trends in education development and technological progress. By optimizing the evaluation system, the school is committed to providing students with higher quality educational experiences and cultivating them into future talents with innovative spirits and practical abilities.

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