Experimental teaching of junior high school science class; Science experimental class.

Experimental teaching of junior high school science class

As we all know, experiment is a basic way for children to acquire perceptual knowledge, and doing experiments is also a most prominent feature of science classes in primary schools and a basic method for primary school students to learn science. Children gain knowledge and understand things by doing experiments, master various experimental methods by doing experiments, improve their hands-on ability, form various skills and develop their intelligence.

Next, I will talk about the role of experiments in lower grade teaching. From the nature of natural science, natural science studies some natural things around students, and the mysteries in natural things are more easily exposed in experiments than in other natural activities. Therefore, the nature of science restricts students from learning science through experiments. Students can reveal the mystery of things by participating in experiments and provide students with the most direct perceptual basis. Judging from the content of science class, what children choose to study and explore in science class are all natural things around them, which are real and objective beings in nature and are closely related to people's production and life. Therefore, students' experiments in inquiry activities are usually tangible, and they can obtain the most concrete, intuitive and vivid knowledge from the experiments. Judging from the teaching process of science class, experimental teaching method and observation method are almost the same, and it is essential to complete the teaching. We all know that the classroom should be a middle school. If students want to know more about specific natural things, they must personally participate in experiments, and experiments are an important aspect of students' practical activities. Now we all advocate a word called "practice", students must personally participate in practice, and experiment is practice.

Therefore, from the characteristics of natural disciplines, from the characteristics of science courses, from the content structure of science textbooks, and from the process of scientific inquiry, it has the characteristics of "practice". In addition, junior high school students know the laws of natural things from concrete to general, from intuition to

Abstraction, a law from sensibility to rationality. In science teaching, we must attach great importance to following the psychological characteristics of students' cognition and let students participate in various small experiments. And from my experience, the students in the experimental class are the most disciplined, which is contrary to some impressions of the teacher. Our teachers all think that it is difficult for students to control discipline once they do experiments, but in fact, students are the most obedient when they do experiments.

What are the characteristics and requirements of these experiments done in the lower grades? Just one word "simple", in fact, the experiments in the lower grades are simple operations, simple experiments and simple equipment. Most of these experimental equipments are very easy to collect and prepare, and they are often seen by students. These things will easily stimulate students' interest in scientific inquiry and make them feel that scientific inquiry is not mysterious. At present, the experiments designed in primary school science textbooks are mainly for students to carry out some simple experimental operations, such as operating alcohol lamps, disassembling toys, studying leaves, etc., in order to cultivate students' operational ability.

Compared with the experimental requirements of middle and high grades in primary schools, the experimental requirements of lower grades have the following characteristics: First, the experimental requirements of lower grades are relatively low, and most of them are for students to master initially and do simply, which is carried out under the specific guidance of teachers. Please note that when children do experiments, they must be under the specific guidance of teachers, and success is an important symbol. Taste failure is more experienced in middle and high grades, because the children in lower grades are very eager for the success of the experiment. If they always fail, they will be disappointed and they will give up. Therefore, in this process, teachers must have appropriate help, even hands-on teaching, so that students can imitate. The experimental requirements of senior students are relatively higher, so they should learn to do comparative experiments in experimental methods. The lower grades are basically simple observation experiments, simple operation experiments and simple verification experiments.

Do it. In addition to comparative experiments, senior students should also do simulation experiments and simply design experiments. Of course, the lower grades are also trying to get him to design experiments independently to prove his ideas. Although there are, the requirements are relatively low. The experimental requirements of middle and high grades are gradually improved on the basis of lower grades, so the experiments participated by lower grades are the most basic and fundamental experiments.

The second feature is that the experimental equipment in the lower grades is relatively simple and easy to find. For example, to prove the existence of air, we only need common materials such as water cups, sinks, handkerchiefs, plastic bags and mud; For example, to play with a small waterwheel, we only need a cork, a few plastic pieces and a metal wire to make a small waterwheel; For example, playing with paper windmills and observing the wind are all common, universal, easy to find and carry, so as to ensure the smooth progress of teaching. In the middle and senior grades, when doing experiments, special experimental equipment is needed, and standardized equipment is used more. For example, it is difficult to study the expansion of heat and contraction of cold, and it is necessary to use alcohol lamps, compare circuits and assemble circuits. In the research of junior year, it is very simple to light a small light bulb, only batteries, wires and small light bulbs are needed. Experiments in middle and senior grades are generally difficult and require certain experimental operation skills. Compared with the experiments in middle and high grades, the experiments in lower grades should be the simplest experiments with the simplest equipment.

The third feature is that although the experiment in the lower grades is relatively simple, it also needs careful design. First, we require that the order of experiments should conform to the logical order of knowledge and the order of students' cognitive operation. For example, in the experiment of "small impeller", I let the students first verify that the water flow can impulse the small waterwheel, which shows that the water flow is powerful. Next, I will let the students discuss how to make the flyer rotate faster. It is necessary to study whether the water level is high or low.

How to make it faster? Generally, primary school students are asked to do it faster. His first reaction was to make the water flush a little bigger and make the hole under the water cup, paper cup or plastic cup bigger. Then I asked if the water flow could only be so much, so that students would think of raising the water level. Then I will make a request. There is so much water and the height is so high. Can you make the small waterwheel faster? You see, the teacher is helping step by step and putting forward higher requirements step by step. Students will know that when the water rushes to the middle, the small waterwheel will be slow; The edge of the impeller rotates rapidly. Next, I asked: Can a water column drive two small impellers? At this time, they know that the impeller can drive another impeller. These experimental designs are actually operated by students themselves in class. This kind of experimental design conforms to the structural design of knowledge, and it goes from shallow to deep, from easy to difficult, from simple to complex in the experiment, which is very consistent with the cognitive characteristics of lower grade children.

In the class of "clockwork toys"-children's clockwork toys, the first task I sent them to learn was to play with clockwork toys and think about why they moved. Next, let the students observe and study to find out the parts that make the toy move. What are these parts like? We open this toy and observe it. Next, continue to study why the clockwork device can make this toy move. At this time, I took a big metal spring. Understand the power of the spring leaf, why the spring does not move when it is loose, but moves when it is tight. It's a little dangerous for every student to play with this, so I gave them a paper clockwork to make them feel that it is very powerful when it is tightened, but not when it is loosened, and then it will be powerful when it is tightened again. At this time, let's observe the principle of clockwork toys. It turns out that when winding a spring, it can store energy, and the stored energy makes the toy move. When the spring is loosened, there is no energy and the toy will not move. Therefore, in this process, it is relatively simple for children to do simulation experiments with paper clockwork when doing research. of course，

We can also use rubber bands. When the rubber band is loose, there is no strength, but when it is tight, there is strength. For senior students, we are allowed to design experiments, and the experimental process and steps are logical and divergent. The lower grades emphasize logic and step by step to succeed. Only by being logical can children's thinking be developed in the process of experiment.

Second, doing experiments in lower grades requires the guidance of teachers. When doing experiments in the lower grades, the teacher's first instruction is to demonstrate-show the children and let them imitate. You must not think that this is a very outdated view. Let the student follow you and he will experience the happiness of success. Don't think that this is limiting students' thinking. Our demonstration is like this. It's not that I do one step and the students do one, but that the teacher demonstrates first and the students imitate. Let the students do it after we finish the demonstration. In this process, children need to remember what we did and then do it by themselves. This process is meaningful.

For example, in my "ups and downs" class, the teacher demonstrated first. The first step is to put the prepared materials into the sink one by one and observe which ones float on the water surface and which ones sink to the bottom. The objects floating on the water surface are classified into one category, and the objects submerged in the water are classified into another category. Then I drew a big table on the blackboard and filled in the experimental results. Through my demonstration, the students know what the steps of the experiment are. If a student follows this order, he can gain knowledge and know what floating is. What is sinking? Identify which objects are floating. Which objects are heavy? In the experimental records, they learn to use symbols to record, tick, draw, up and down arrows to express their understanding of the ups and downs of specific objects. In fact, it is from concrete understanding to description of language, that is, from concrete thinking to abstract thinking training. When I finished, the materials I sent to the children were not exactly the same as the materials I demonstrated, but the way I did it was to let the students take care of it.

I did it. Next, when the students are finished, I will demonstrate how to make floating objects sink and how to make sinking objects float. After I did it, the students gained the knowledge of ups and downs. At this time, they can use this knowledge. Next, this is a game. In this process, we not only let students imitate the teacher's methods, but also encourage him to think of methods that the teacher has not done. Can you do it too?

The experiment of "small waterwheel" is very simple, but before I do it, I must first explain the procedures and essentials of operation. Although junior students are simple, the procedures, key points, experimental steps and matters needing attention must be clearly explained, especially the tasks. What students should observe in the experiment, and the main points of observation should be indicated. For example, in the experiment of small water wheel, especially at the beginning, the relationship between the flow rate and the force was put forward by the students themselves, so I want to remind them that a cup hole is small and the flow rate is small, and a cup hole is large and the flow rate is large, which is why I want to tell them to be at the same height when hitting the small water wheel. What is the same height? That is, the same child lifts it to the same height at the same time. When the second link is carried out, we explore the water level and water flow. At this time, it is necessary to ensure that the water flow remains unchanged. At this time, it is necessary to replace the children's coarse-hole water cups with fine-hole water cups, so that they can reach the speed just now with fine-hole water. We must ensure the same cup, the same water flow, but different heights. What we asked them to observe was what happened to the rotation of the small waterwheel because of the large water flow. What happened to the rotation of the waterwheel when the water level was high or low? What is the relationship between the rotation speed of the waterwheel and the water level? In this way, when students experiment in groups, they can transform the teacher's intention into the knowledge and skills they consciously acquire.

The third is to help students make a summary. Junior students don't do experiments for the sake of doing experiments, but gain the most direct knowledge by doing experiments. Teachers should help students make language summaries, because students' language ability is relatively weak, and help them sort out the experimental conclusions. Only in this way can students understand the essential attributes of things, especially some experimental purposes. We should report by students in groups first. Report the facts, and then we can ask the whole class to help them sum up the experiment and get a knowledge. At this time, teachers will draw conclusions from the acquired knowledge, then contact our daily life and guide them to apply it, so that their ability will be enhanced.

For example, another experiment is to study light. If you study light in the lower grades, many people will think that it is for the upper grades. In fact, we only study objects, which requires experiments. When doing the experiment, I gave each child a big leather shoes box. I punched some holes in the leather shoes box, but I sealed all the holes in class except the one in front. I asked the students to observe the objects in the box. This is really an interesting activity. I put a little panda in it. The first time for students to observe is whether there is anything in it, the second time is whether there is light in it, and the third time is what is the relationship between light and objects. You see, what is the logic of my every activity? Students can't see objects at first. He looked at the contents of the box through a small hole, but he couldn't see when there was something in the box. Why? Because there is no light. At this time, we open some small holes in the top of the box cover. When we open the hole, there are two holes, one is the observation hole and the other is the light hole. At this time, he will clearly see the light. Because the position of the hole is different, the clarity of the object is also different. At this time, we opened nine small holes and covered them one by one.

Hole observation, through the change of light, see the clarity of the object. So students' attention is different every time. For the first time, students pay attention to whether there is an object, for the second time, students pay attention to whether there is light, and for the third time, students pay attention to the change of light intensity in the box with the light hole slowly opened. In this way, students can connect the phenomena they see with the essence, and these three experimental activities are promoted one after another.

When we are in class, especially when doing experiments, we should be especially good at trying to figure out students' psychology and understand their thoughts. Only in this way can targeted teaching be carried out. If you want to understand students' thoughts, you should be good at observing students' performance in the process of inquiry activities and try to show students' thinking process in various inquiry activities. Therefore, when doing experiments, students should actively watch and listen, put themselves in the children's shoes, pay close attention to the problems and special performances of students in the process of inquiry, and think about how to guide children's thinking in the next step. Let's take the experiment that seeing an object needs light as an example. The first observation found that students have three behaviors. Good students look inside through the hole, and students who are a little more flexible pick up the box and aim the hole at the light outside. The third group of children is particularly fierce. If a child comes to me and asks me directly, I want to have a look inside. Just open the lid, so I will focus on those students who point the hole at the light and open the lid, and let them tell me why you are doing this. The students said, "I couldn't see anything at first, because it was dark inside, so I wanted to open the lid, because I had to open the lid to see the panda pattern inside." The students' ideas came out, so I provided resources for the second activity. I told the students that we don't need to open the lid now because I am on it.

Some small holes have been made, which means we can remove one at will, but only one at a time. Let's see what we see each time we remove it. So the students removed a hole and slowly opened it. Of course, in the end, we can completely open the lid. When the lid was opened, we finally gave the panda card inside to the students. Through such activities, students' thinking will be constantly impacted and sublimated.

Regarding this light, I also have an activity to study the transparency of objects. When we find that light can pass through some objects, I can ask students to discuss which objects can let light pass through. The student said, glass window, and I asked the student, "What will our whole classroom look like if we use brick windows?" The student said, "The classroom is very dark." I said, "Really? In the evening, it is dark outside and we are still working in the classroom. " The student said, "Turn on the light". At this time, he knew that light is closely related to our lives, which is his normal extension.

Finally, let's sum up. First of all, we should help students. We should let students feel and taste the success of the experiment. The second is that we should guide students. When we help students, we should try to show them and let them imitate us. When we guide students, we should let them observe key places or important parts. Third, we should help them improve their conclusions. Children in lower grades mainly think in concrete images, so we have many exploration and experience activities, such as observation, classification, experiment and measurement. In these activities, in fact, all activities, especially experimental activities, must be close to the thinking of lower-grade children. For example, when we studied toys, we found that the clockwork was completely loose, and he stopped. Students can't understand that clockwork stores energy, but by playing with paper clockwork, abstract concepts can have a concrete and vivid perception.