Chemical experiment plays an irreplaceable role in completing the task of chemistry course. "Chemistry Curriculum Standard" emphasizes improving students' scientific literacy. Attach importance to the connection between science, technology and society; Advocate diversified learning methods based on scientific inquiry. Scientific inquiry is a way of learning and the main content of chemistry course in compulsory education. Therefore, the contradiction between the lack of chemical experimental resources and the new curriculum reform is prominent, which makes chemistry teachers lack the guarantee of experimental resources in the teaching process, which not only hinders the advancement of chemistry curriculum reform, but also shakes the belief of chemistry teachers, thus affecting the success or failure of chemistry curriculum reform.

The contradiction between the lack of chemical experiment resources and the implementation of the new curriculum reform is more prominent. Chemical experiments should be done to cultivate students' scientific literacy. So, how to solve the contradiction between them? As long as we solve the problem of lack of chemical experiment resources, this contradiction will be solved. At present, the teaching funds of schools in many areas, especially rural junior high schools, are still relatively tight, and it is difficult for schools to solve them. But chemistry teachers and students can also find ways to give full play to the master role of teachers and students. Therefore, the effective solution is for teachers and students to develop chemical experiment substitutes and use them to complete chemical experiments. Practice has proved that all experiments in junior middle school chemistry textbooks can be completed with chemical experiment substitutes, which can solve the problem of shortage of chemical experiment resources and promote the new curriculum reform.

First, junior high school chemical experiment substitutes

For a long time, chemical experiments, like experiments in other disciplines, have been influenced by "exam-oriented education", and the negative understanding of traditional experiments is heavy pollution, high consumption and difficult to popularize, resulting in the phenomenon that "teachers talk about experiments and students write experiments", which is undoubtedly not conducive to the cultivation and improvement of students' quality.

1. What is a substitute for chemical experiments? Chemical experiment substitutes refer to instruments and materials that are easy to obtain and make, and can replace conventional experimental instruments and reagents to achieve experimental purposes.

2. What are the characteristics of chemical experiment substitutes? Easy to get, available, green and life-oriented.

Second, the development of junior high school chemical experiment substitutes

Many middle schools, especially rural middle schools, are difficult to let students carry out various experiments or activities according to the requirements of the new curriculum standards due to the limitations of objective conditions. In order to make up for these shortcomings, teachers should actively develop and use experimental substitutes to complete experiments and other feasible experiments and activities in teaching materials.

1. Principles and precautions for collecting and developing chemical experiment substitutes

(1) principles of collecting and developing chemical experiment substitutes

① Guide students to collect, make and use substitutes along the idea of "experimental supplies-daily necessities-alternative supplies-alternative production process-inspection process-practice process".

(2) Teachers should do a good job in organizing and guiding, and pay attention to safety issues.

(2) Matters needing attention in collecting and developing chemical experiment substitutes

(1) put safety first when collecting and making, some of them are far away from teachers and lack guidance, especially glass instruments, and some still keep potions. We must put safety first, conduct more safety education, and let students operate as required. (2) Pay attention to the classification of instruments and drugs. When establishing the substitute laboratory box, we must pay attention to the classified preservation of instruments and drugs, including the reasonable placement of instruments and the safe preservation of drugs.

2. A Collection of Chemical Experiment Substitutes

(1) The teacher will demonstrate how to collect. First, collect the most easily available supplies to stimulate students' interest, such as infusion tubes, injection bottles and infusion bottles. Then collect and develop hard-to-get items, such as making test tubes and assembling experimental devices. Teachers collect some difficult and dangerous instruments that students can't collect and make, such as homemade test tube clamps and homemade tripods.

(2) Students collect substitutes collected by students, which are easily obtained from students' daily life, such as waste light bulbs and waste ballpoint pens. It is also easy for students to make substitutes, such as droppers. Just cut off the drip pot of the infusion tube and seal one end. Students can use all available time and place to collect and develop experimental substitutes.

(3) Collect instruments that can be replaced by chemical experiments. Glass: Funnels, small wine glasses, infusion bottles, waste light bulbs, injection glass bottles with different specifications, etc. Plastics: syringes, infusion tubes, all kinds of straws, lotion bottles, small watering cans, etc. Metals: cans, small iron needles, tweezers, paper clips, etc.

Experimental box is an important part of chemical laboratory construction, an important link to improve students' scientific quality and an important step to collect experimental substitutes. Open the laboratory to students in their spare time, and encourage students to carry out experiments and exploratory experiments independently.

Third, the use of junior high school chemical experiment substitutes

Case 1 One set of equipment is multi-purpose.

Instruments: covered medicine bottle (instead of conical bottle), penicillin bottle (instead of gas collecting bottle), syringe (instead of separating funnel), infusion tube (instead of catheter), connected with the complete set of devices.

Drugs: hydrogen peroxide, manganese dioxide

Put a small amount of manganese dioxide into the medicine bottle, put a small amount of hydrogen peroxide into the syringe, slowly inject it into the medicine bottle, use a penicillin bottle instead of a gas container to collect oxygen, check and fill it up.

The above device is also suitable for the experiment of "solid+liquid reaction without heating".

Case 2: Study on Eggshell Composition

Instruments: homemade reagent bottle, homemade dropper, homemade test tube (or glass), glass sheet.

Medicine: egg shell, clarified limewater, vinegar.

Put the egg shell into a homemade test tube (or glass), drop vinegar with a homemade dropper, and put a glass piece soaked in clarified lime water on it. Observe that there are bubbles, and the clarified lime water becomes turbid, and analyze that the egg shell contains calcium carbonate.

The above are some researches of the author in teaching activities. Practice has proved that these studies not only solve the shortage of experimental instruments and drugs, but also solve the problem of lack of chemical experimental resources. It promotes the smooth progress of the new curriculum reform and cultivates students' practical ability, which is not only economical and environmentally friendly, but also embodies the concept of green chemistry. Ensure the smooth progress of experimental inquiry activities, let students at different levels move, truly achieve the development of each student and truly cultivate students' scientific literacy.