Silicon is ranked second in the earth's crust and is widely known as a non-metallic material. Silicon is closely related to the growth of crops. In this paper, the research history of silicon was reviewed, and the properties of silicon, distribution characteristics and existing forms in soil were introduced. The research progress of silicon in improving crop stress resistance, such as drought resistance, lodging resistance, salt alkali resistance and high temperature resistance, was reviewed. The role and mechanism of silicon in coordinating and promoting the absorption of nutrients by crops, alleviating the toxic effects of heavy metal ions and resisting the invasion of pests and diseases were reviewed. The mechanism and conditions of silicon to regulate crop growth were analyzed, and the absorption and transport of silicon by crops were analyzed from a genetic perspective. The important role of silicon fertilizer and silicone surfactant in promoting the sustainable development of agriculture was discussed.

Based on the principle of "combination of three sequences", this paper analyzed the arrangement of chemical equation knowledge in different stages of junior high school and senior high school. The arrangement of this part of knowledge in the textbooks published by People's Education Press met the requirements of combining the logical order of knowledge, the cognitive order of students and the psychological development order of students. This paper also gave some teaching suggestions.

Taking five sets of senior high school chemistry textbooks published by people's education press since China's reform and opening up in 1978 as the research object,studying the contents of the structure of matter, this paper found that the selection of contents of the structure of matter in senior high school chemistry textbooks showed the pendulum phenomenon,and the structured organization of contents showed increasingly clear in nearly 40 years, and then this paper provided some written suggestions for the new senior high school chemistry textbook.

According to the new turn of curriculum revision, primary schools would open science courses in grade 1. In order to promote the students' understanding of big idea in science learning, the question that what knowledge should be learned had attracted increasingly attention. In this paper, based on the perspective of big idea, the learning of matter was taken as an example to discuss what grade 1 students needed to know about matter and how to provide corresponding teaching.

Focusing on the development of students' core literacy of chemistry, the teaching value of colloid is analyzed. By setting a series of contexts about chemical history, the students are guided to put forward questions based on the chemical history, and then to lead the learning activity with questions. And in this way, students participate in inquiry activity along the footprints of scientists, collect evidence through independent experiments, and then reason based on experimental evidence, the essential characteristics and properties of colloids are constructed through this series of activities, and further, the core literacy is developed.

Based on chemistry core literacy,this paper analyzed the scientific discovery process of methane by "opening the door to the second natural world" with following the clues of "history" "activity" and "knowledge". It allowed students to experience the process of the formation of scientific concepts, understand the nature of "grass changing gold", and effectively combine teaching model with chemistry core literacy. This kind of teaching design enables students to experience the process and methods of chemistry development, and feel the charm and development achievements of chemistry in order to increase students' interest in learning.

Teachers guided students to make full use of the learned knowledge of iron, iron oxidation, determination of iron, as well as experimental skills of the dissolution, filtration and so on. By means of practical learning of the new information and new methods, the students could critically absorbed the primary knowledge in the textbooks and effectively improve the understanding and application of the related information.

Taking the scientific practice of "comparison of vitamin C content in fruits and vegetables" for example, this paper expounded the design principle of scientific practice, the design of the activity target, the design of the teaching process, teaching implementation strategies and the effect of the activities. It showed that scientific practice played a unique role in cultivating and improving students' scientific literacy. It pointed out that teachers should attach importance to the research and development of scientific practice and should constantly improve their scientific literacy level.

Based on the learning perspective of cognitive psychology, this paper discussed the stoichiometric system with amount-of-substance as core, pointed out this system could be divided into two parts from the point of view of teaching strategy:knowledge system and operating system. Its knowledge system mainly belonged to declarative knowledge, while the operating system mainly belonged to procedural knowledge. According to the cognitive characteristics of declarative knowledge, inquiry teaching was designed to embody the network structure and function of this system, and higher-level thinking operation, such as productive self expanding process, was designed according to the cognitive rules of procedural knowledge. Resulting from the above research, a small step productive strategy was formed to solve the practical problems with the inquiry teaching of construction of stoichiometric system with amount-of-substance as core. It meant that scattered knowledge was replaced by structured system, daily metaphor was replaced by logical thinking and mechanical calculation was replaced by intelligent production, thus explored more effective strategies and methods for the teaching of stoichiometric system with amount-of-substance as core.

Taking CCITIAS as a research tool, this paper analyzed the chemical experimental classroom behavior of an excellent teacher's chemistry experiment class, and found that the excellent teacher could use multiple behavioral combinations, promote effective language interaction between teachers and students, highlight "leaving blanks" in the classroom, create "spatio-temporal" experimental classroom.

Green chemistry is the premise of the sustainable development of science, technology and social. Based on the previous studies, this paper built the assessment framework, developed the test tool, implemented the test, analyzed the data and revealed the condition and development characteristics of senior high school students' "green application" competence. This study found that the level of the "green application" competence and discipline ability were consistent and the gender difference of "green application" competence development was not significant. Thus, this study had reference and enlightenment function to the high school chemistry teaching to cultivate students' "green application" competence.

This paper explained the meaning of scientific core literacy of preschool teachers from three dimensions of knowledge, method ability and emotional attitude. In order to find out whether the five-year preschool education major students have scientific core literacy of preschool teachers, a questionnaire survey was conducted on the scientific core literacy of 403 students of grade 2015 majoring in five-year preschool education in Tangshan. Through statistical analysis of the survey results, this paper revealed the status of students' scientific core literacy, and analyzed the affecting factors. On this basis, put forward some suggestions for training five-year preschool education students to have the scientific core quality of preschool teachers.

Qualitative detection of the anthocyanin in several common fruits and vegetables was carried out with the hand-held miniature laser fluorescence spectrometer. The experiment indicated that the 405 nm laser could effectively excite the fluorescence of the anthocyanin with more distinct feature than that of 410 nm laser. The experimental results are good consistent with literatures:mulberry, black currant and strawberry contain anthocyanin, but tomato and garlic don't contain. This experiment was simple, safe, reliable, and with high sensitivity. It could be used as demonstration experiment and students' comprehensive inquiry experiment.

"Blue Bottle" experiment and Iodine Clock reaction are similar on the following aspects:being historic, funny, color changing between blue and colorless, and being used in inquiring instruction of chemical dynamics. But they are different in the following points:development, mechanism, phenomena and so on. This paper suggested that iodine clock experiment should be included in our chemical education.

This paper used SPSS25.0 statistical software to design orthogonal experiment for Briggs-Rauscher reaction. The best experimental condition was obtained through statistical analysis, that was, temperature was 30℃, the concentration of sulfuric acid was 2 mol/L and the stirring time was 8 seconds. This paper used an ORP sensor to analyze the electric potential variation curve of the B-R oscillating system, combined the literature and the curve to expound the reaction mechanism from the perspective of thermodynamics and kinetics. Based on macroscopic, microscopic, symbolic and curves, tetra-representation analysis could help students understand the nature of the micro-reaction behind the interesting experiment was the mutual transformation between different valence states of iodine.

Taking the reaction of Fe³⁺ and I^- as an example, this paper combined the concrete primary battery with the abstract chemical equilibrium concept, and presented several knowledge points such as redox reaction, chemical equilibrium and movement, primary battery and etc simultaneously, which was helpful for students to construct systematic and structured integrated knowledge network. This paper improved the experimental equipment and the amount of reagents, determined the best conditions for the classroom demonstration of this experiment, and provided teaching suggestions for teachers' teaching.

Base on the question of college entrance examination of Beijing, this paper calculated the electromotive force (EMF) and equilibrium constant of the reaction (Ag⁺+Fe²⁺=Ag+Fe³⁺) according to standard electrode potential, and calculated the nonstandard state electromotive force of the reaction, proved that its reverse reaction could be accomplished theoretically. Then this paper designed primary battery, and changed ion concentration to realize Ammeter pointer reverse deflection to verify reversibility of the reaction.

In some chemistry exams for senior high school entrance examination, test designers believe that the differences in the total mass before and after the solid-liquid reaction is the mass of the gas produced. This paper discussed the solid-liquid reaction experiments of producing H₂, O₂ and CO₂ by using a beaker; the results showed that those exams had a certain degree of one-sidedness. Understanding this experimental fact could help chemistry teachers set reasonable and factual questions, and cultivate students a scientific attitude to respect facts and pursue scientific truth.