This article analyzes the possibility of hair shape and color changes starting from the structure and composition of the hair, analyzes the chemical principles of perm and hair dyeing, explains the essential reason for hair perm first and then dyed, treats the pros and cons of perm and hair dyeing dialectically from a chemical perspective.

Under the background of the development demand of scientific and technological innovation in China and the plan of strengthening teachers in basic education in the new era, this paper discusses the new mission faced by the discipline of chemistry pedagogy: to provide strong support for cultivating the innovation awareness and innovation ability of normal students, and to provide strong guidance for basic chemistry education to cultivate students' innovation awareness and innovation ability. The new challenges to achieve the new mission are analyzed: to enhance the understanding of the content of chemistry and enhance the ability of chemistry professional dialogue; Integrate chemical education, educational psychology, philosophy of science and other fields, and clarify the theoretical basis of chemical education; Deeply reflect and integrate the research achievements of chemical education at home and abroad, and clarify the academic nature and unique advantages of chemistry pedagogy; The gap between chemical education research and chemistry classroom teaching practice should be bridged; Strengthen the integration of chemistry education research achievements and chemistry teacher education curriculum; Further enhance the external recognition of chemistry pedagogy.

This paper analyzed the content structure and development localization of core literacy in the learning theme 1“scientific inquiry and chemistry experiment” of the Chemistry Curriculum Standards (2022 Edition) for Compulsory Education, expounded the content requirements and main changes, interpreted the academic requirements of literacy orientation, and elaborated the teaching tips of the learning theme 1. It provided teachers with suggestions on teaching strategies, learning activities and situational materials, promoted teachers to actively carry out the teaching exploration of the learning theme 1.

According to the national conditions, the SEC consistency analysis model is localized, and the consistency analysis framework based on the chemistry discipline ability is constructed, and the consistency between the curriculum standard and the exercises in the three versions of new high school chemistry textbooks on the theme of “common inorganic substances and their applications” from the two dimensions of content theme and understanding level is analyzed. The results show that the three editions of the new high school chemistry textbook exercises and curriculum standards are statistically significantly consistent in content themes and cognitive level dimensions. On the basis of consistency research, the themes of the exercises in different versions of textbooks and the distribution of cognitive level are analyzed, and suggestions on the compilation of textbook exercises and use strategies are put forward.

Understanding the nature of science is an important goal of science education. The education of the nature of science advocated in the curriculum standards plays an important role in the cultivation of students' view of the nature of science. By constructing a three-dimensional analysis framework for the content, presentation, and complexity of the nature of science, this research conducts a longitudinal comparative analysis of the education content of the nature of science presented in the “content standards” entry in the 2003 and 2017 editions of senior high school chemistry curriculum standards, and finds that: the performance dimension of the content of the nature of science education in 2017 edition is more comprehensive; the presentation mode is more recessive than the dominant; and the advanced nature is insufficient. Based on this, the following suggestions are put forward: strengthen the multi-dimensional integration of the nature of science in the curriculum standards to reflect the advanced nature; promote teachers' understanding of the educational value of the nature of science and establish an evaluation system; excavate the education content carrier of the nature of science and integrate chemistry knowledge.

Supramolecule is a molecular aggregate formed by non-covalent interaction of two or more molecules, which is an important direction of chemical research. In 2020, supramolecule, molecular recognition and self-assembly have been introduced into middle school chemistry textbooks for the first time. This paper explains supramolecule, molecular recognition and self-assembly in the new textbook, and expands and extends the related content, in order to provide resources for teachers to prepare lessons deeply and students to learn further.

This paper clarifies the relationship among the factors influencing item difficulty through the main-factor analysis method. On this basis, the main factors influencing item difficulty of senior high school achievement test are found from the three dimensions of problem representation, problem solving and result output. Next, through the writing and testing of items of alternate forms, the difficulty sequence of factors of different types and corresponding grading rules are established. After assigning values to the 7 factors of all the items of alternate forms, the linear regression method of machine learning is used to construct the model. In addition, the model is tested with data generated from part of the constructed items in college entrance examination chemistry Jiangsu paper. The predicted value of the model and the measured value have a good degree of fit, indicating the application value and promotion significance of the model.

Taking the teaching fragment of “ancient and modern water purification”, that is, “water purification”, as an example, this paper tries to apply the historical situation of Chinese traditional water purification process to the chemistry teaching practice in junior high school. Students experience the core steps of the water purification process, such as “sedimentation, filtration and adsorption”, and self-made simple water purifiers. Based on the local reality, guide the students to analyze the Xiamen water quality test report, introduce the latest water purification products of Xiamen “Sanda membrane” company, and compare the advantages and disadvantages of the products with the “single soldier field survival life straw” made in the United States. Finally, it advocates students to protect water resources and sublimate the emotion of loving water and hometown. So that students can not only experience the subtlety of Chinese traditional water purification technology, lament the crystallization of the wisdom of the ancients, but also feel the value of chemistry to human production and life. Students can also master the modern basic water purification process and apply it to daily life, enrich the vision of the discipline, cultivate the spirit of speculation and enhance the sense of social responsibility.

This paper carries out neutralization reaction teaching from the perspective of “macro identification and micro analysis”. First, this paper takes the conventional experiment as the carrier to understand the external performance of neutralization reaction from the macro perspective, then takes the model and animation as the carrier to understand the micro process of neutralization reaction from the micro perspective, and then takes the digital experiment as the carrier to understand the internal essence of neutralization reaction from the macro and micro perspective, and finally, experiences the application value of neutralization reaction in connection with the reality of production and life. With this design, students can deeply understand the nature of neutralization reaction, enhance the understanding of chemistry and cultivate the core literacy of chemistry.

This new-designed class changes the traditional teaching method of chemistry review class by taking the real situation as the carrier and using “exploring the mystery of the steam eye mask” as the theme of the project, which can lead the students to carry out the specific review of iron elements in depth. It also elaborates the teacher's pre-class analysis of this part of teaching content in detail, which includes the way of establishment, planning and implementation of this project. By completing the two tasks of “designing an experimental scheme to prove the existence of iron” and “exploring the effects of activated carbon and sodium chloride on iron rust”, the students enhanced their interest in the discipline and systematically reconstructed the properties of iron. Through the handheld technology to monitor the oxygen concentration and temperature changes so as to explore the role of eye mask components, students' scientific inquiry ability transitioned from qualitative to quantitative, realizing the deepening and upgrading of scientific inquiry literacy. By watching science popularization videos to learn about frontier science,students could also broaden their career awareness,develop their dialectical thinking and cultivate their scientific spirit.

In order to solve the real problem of “why glass stopper is not used in reagent bottles to preserve NaOH solution”, three teaching sections are designed: using classification methods to recognize substances,classify substances and synthesize substances. From the perspective of material composition and material change, this paper classifies materials and constructs the classification view. In addition to completing the knowledge structuring, it focuses on the cognitive perspectives and ideas based on the classification and transformation of substances, finds and experiences the breakthrough point and thinking framework for the study of new substances in unfamiliar situations, and develops students' core literacy of chemistry discipline.

Taking the “carboxylic acid” section of senior high school chemistry as an example, guided by the big idea of “chemistry originates from life, and structure determines nature”, combined with a series of real situations, the nature of acetic acid, carboxylic acid and carboxylic acid derivatives are structurally integrated, and the teaching is carried out in a spiral way, which conforms to students' learning psychology, promotes the establishment of students' disciplinary knowledge structure and cognitive structure, and highlights the dominant position of students in teaching, The cultivation of students' subject core literacy will also promote the secondary growth of teachers and achieve mutual benefit between teaching and learning.

This paper makes a new attempt and reflection on the teaching of “relative atomic mass”, discusses two perspectives of in-depth understanding of “relative atomic mass”, and carries out students' independent inquiry activities to further realize the sustainable development of students' thinking and cognition. This is also an exploration and attempt based on the connection between junior high school teaching and senior high school teaching. It can not only be applied to the in-depth understanding of “relative atomic mass” teaching in junior high school, but also can be applied to the cohesion course of “amount of substance” teaching in senior high school.

Model and modeling are important components of chemistry core literacy. Computer modeling plays an important role in guiding students to build models and learn knowledge, because of the benefits on visualizing abstract phenomena and creating an inquiry-based learning environment. Based on the advantages of computer modeling, this paper developed an inquiry-based teaching design by using a computer modeling tool, SageModeler to teach chemical reaction rate. This paper aims to provide an insight of how to use a computer modeling tool to build, evaluate, develop, and optimize students' mental models in a chemistry classroom. Furthermore, teachers and researchers may implement this exploratory modeling instruction in the real classroom to increase students' comprehension of the nature of models, develop modeling competency, and generating a clear understanding of chemical reaction rates.

In the present study, a self-made questionnaire concerning the theme of “primary battery” was designed. The knowledge of instructional strategies (KoIS) of 95 in-service high school chemistry teachers in Hebei province were surveyed. Using single factor analysis of variance and multiple comparison LSD, the deferences and performance characteristics of KoIS between novice, proficient and expert teachers were compared and analyzed from the following five dimensions: selection, application, adjustment, feedback and evaluation of teaching strategies and representations. Based on the findings of this study, several relevant suggestions were given which would provide reference for promoting the rapid improvement of high school chemistry teachers' KoIS level.

Taking the innovative experimental research on “preparation of environmentally friendly degradable film” as an example, this paper explores the use of STEM education mode to guide students to prepare an environmentally friendly film with fast degradation speed and less pollution through their knowledge. Through theoretical learning, practical exploration, performance test and other experimental links, the optimal reagent ratio is finally determined. Under the STEM concept, the theoretical knowledge is integrated into the engineering design of environmental protection materials to realize the integration of disciplines.

Employing classroom observation, this research investigated 27 junior high school chemical experiments teaching cases in Shunyi district, Beijing, in terms of inquiry level and students' high-order thinking activities. The results showed that the general inquiry level was still at primary stage and the participation of problem posing by students was especially low; teachers paid more attention to full process of scientific inquiry; students' high-order thinking was reflected in varying degrees, including that the thinking of variable control, evidence reasoning and abstract generalization was developed obviously, whereas the thinking of hypothesis creating, model cognition and criticism and questioning was lacked.

Ancient philosophers of different civilizations regarded fire as an element, a material principle. In the 17th century, mechanistic philosophers believed that fire was composed of the fire particles. In the 18th century, under the paradigm of phlogiston theory, fire was regarded as an aggregate of phlogiston a compound; under the paradigm of oxidation theory, fire was considered to be a fluid substance, composed of calorique. In the 19th century, the understanding of energy revealed that fire was a form of energy transformation. In the 20th century, fire was found to be a kind of plasma. From the form of energy transfer to plasma, the concept of fire has been developed in the integration of multiple disciplines. The exploration process of “fire” promotes the development of science and technology, scientific research methods and scientific thought, and has enlightenment on science education.

The fourth question in the preliminary test questions of the 35th Chinese Chemistry Olympiad Preliminary in 2021 was analyzed in detail. Using the model established by oneself, the students' understanding of the crystal structure of dry ice was deepened, the related unit cell parameters and atomic coordinates were calculated, and the reason why the dry ice crystal was not a face-centered cubic but a simple cubic lattice was explained. Based on the implicit relationship between material composition and structure, the possible structures of each molecular formula were cleverly deduced with the help of unsaturation. The problems of the test questions were also discussed at the same time. Some pieces of teaching advice were provided.