Learn more about several common rocks (revised draft)? 0? three

1 Meet several common rock teachers: Xu from Taizhou Linhai Dayang Primary School; Teaching objective: scientific concept:1; A preliminary understanding of slate, sandstone, granite, marble, limestone, conglomerate and other common prominent features. 2. Different kinds of rocks have different characteristics in structure and structure. Process and method: 1. Observe, record and describe the color, texture and structure of several common rocks. 2. Identify rocks according to their characteristics and related data. 3, according to the need to observe and compare rocks, and access to relevant information. Emotional attitude values: 1. Recognize the importance of careful observation, comparison, recording and description. 2. By talking about the organizational form of guessing, cultivate students' questioning awareness and interactive effectiveness in scientific communication. 3. Cultivate interest in collecting and studying rocks. Emphasis: Observe, record and describe the characteristics of several rocks. Difficulties: 1. Describe the rocks. 2. Identify rocks according to their characteristics and comparative data. Group experiment: 1 granite, 2 marble, 3 limestone, 4 slate, 5 sandstone, 6 conglomerate, tweezers, dropper, drop bottle, dilute hydrochloric acid, magnifying glass, water cup, wet towel and glass dish. Demonstration experiment: rock specimen, dropper, dilute hydrochloric acid, dropper, glass dish and related courseware before class: Teacher: Let's play a guessing game first. The teacher described the physical characteristics of a classmate in our class. Please guess who he is. He has black hair, two eyes, two ears, a nose and a mouth. Who is he? Teacher: In other words, we can't tell who he is! How do you think the teacher should describe it? Yes! Only by describing the obvious characteristics that distinguish this student from other students, preferably unique, can others easily guess. Teacher: Which student can describe the obvious characteristics of a classmate? Student: Description (2) Teacher: (You succeeded! Explain that you have described the obvious characteristics of this classmate, or: Does this classmate have the most obvious characteristics? Now change the way. Who will describe it and let the teacher guess? I can guess that you will succeed! Who will describe it? Health: Describe it. Teacher: To tell the truth, the teacher really can't guess at once! Can you describe the most obvious characteristics of this classmate? It seems that when talking about guessing games, the speaker must grasp the obvious characteristics to describe them. The person who guesses must be familiar with and know the person who is guessed. Teaching process: 1. Introduce the topic (1). Please invite the protagonist of today's quiz to appear (show some common rock pictures). They are common stones in our life. To talk about and guess these rocks, we must first understand them. (Write on the blackboard: Know several common rocks) 2. Observe the rock experiment (9 points) 1. Discuss observation method 2. (Show: Granite, Conglomerate) We learned to observe rocks with our own senses. Now, how are you going to observe the rocks? What do you want to observe about rocks? 2. Exchange feedback ★ Look: See what? (color, shape, stripes, etc.). Feel free to show pictures such as stripes and biological traces (board: look) In addition to seeing with eyes, we can also observe with a magnifying glass or microscope. (Board: Magnifier) Guess what else you can observe with a magnifying glass? (Random display of stripes, spots, biological traces, etc. Rock) ★ Touch: Touch what? (Rough or smooth) (Board: Touch) Question: Why do some rocks feel rough? Exit: Because there is something on some stones. (This thing is called particles. (Board: particles) shows pictures of particles. (Large particles can be felt or seen.) Experts divide rock particles into three grades, namely coarse particles, medium particles and fine particles. Particles larger than sesame are coarse particles, those smaller than sesame and larger than flour are medium particles, and those invisible to the naked eye are fine particles. Particles and particles are combined together, some are relatively tight and some are relatively loose. If the particles fall out when you pinch them with your hands or scrape your nails, they must be loose. ★ Listen: Listen to what? (Board: Listen) (Stones knock against each other to listen to sounds, some of which are crisp and some are turbid) ★ Smell: Smell what? (Smell) (Board: Smell) 3. In addition to these observation methods, we will learn another observation method, that is, drop dilute hydrochloric acid to see the reaction. (Board: Dropping Dilute Hydrochloric Acid) The teacher introduced while demonstrating: In the experiment, first put all the stones in a glass dish, then gently pinch the dropper, and the dilute hydrochloric acid will be sucked up, then drop a drop of dilute hydrochloric acid on each stone at the same time to see the reaction of the stones, and finally put the dropper back into the dropping bottle. Dilute hydrochloric acid is different from this glass of water on your desk. Very corrosive, contact with skin and eyes will be corroded, so be careful when operating. 4. Learn to observe records (in fact, many contents of rocks can be observed by these methods. Please look at this observation record. Is there anything you don't understand? Feel free to show various pictures to help you understand bedding, pores, spots, biological traces, etc. Please pay attention to which rock you choose. First, write down the number of this rock, in which the rock color and particle color need to be described and filled in. If other characteristics are consistent or consistent, just tick "√" in the box. 5. Show warm tips. Before learning tips, there are several reminders: a. Choose your favorite rocks (at least 4 pieces) and carefully observe their main characteristics; B, be careful when dripping dilute hydrochloric acid, the rock dripping dilute hydrochloric acid should be clamped with tweezers and cleaned with clear water; C, put the experiment of dropping dilute hydrochloric acid at the end of all observation activities; D. After the observation records are finished, please arrange the experimental materials and prepare to describe the characteristics of rocks in your own words. Third, students observe the experiment (13) 1, and begin to observe the experiment. After about 8 minutes, please ask the material clerk to collect dilute hydrochloric acid. 3. Rock Observation Record Table The first experimental group experimenters: the remarkable characteristics of rocks numbered by rocks, new observation methods, color tapping, listening, rock structure, the shape of rock particles, reaction stratification by dropping dilute hydrochloric acid, pore spots, stripes, biological traces, particle color, particle thickness, particle structure, fine particles in coarse particles, loose and tight bubbles, no bubbles, turbidity and crispness, and some. 2. Teachers' patrol guidance, selecting three groups of representative experimental records (medium, good, good and good) 3. (Music begins) Ask the material clerk to sort out the experimental materials. Fourth, the experimental report (8 points) ★ The students observed it so carefully just now, so there must be many discoveries, right? Choose your favorite rock and try to describe the characteristics of the rock in the group. The teacher will patrol to guide the description. Choose (average, good, good, good students) to type ☆★ Say 1 student to describe, and the other students will take out their records and listen unilaterally. Collective evaluation (Q: Did other students find anything different? Who can describe your findings in their own words with the help of the record sheet? ★ (Slide shows rocks randomly) (Name two students to describe) Incentive evaluation: You found a lot! I think this is inseparable from your careful observation. Or: I think you can describe it more perfectly if you observe it more carefully! ★ (Showing two stones, No.3 and No.4) These two stones look very similar, and the teacher always can't tell them apart! Who will compare and describe the similarities and differences between these two rocks? ★ Student Description★ Comment (Did you hear that? What is the most obvious difference between these two rocks? ) Incentive evaluation: You are really capable of distinguishing two seemingly identical stones so clearly! This stone was awarded to the future geologist. V. Identifying rocks (6 points) 1. Just now, the students described the rocks. Next, let's see how geologists describe rocks. Students can look at the big screen or read the 68 pages of rock data in the book. 2. Students read 3. Please name the six kinds of rocks we have just observed according to these data. (Showing the connection problem) How can you tell? Tell me the reason (be sure to tell me the distinctive features that distinguish me from other rocks. ) 4. Yes! We can identify rocks according to their distinctive features, so are our judgments correct? Let's play a game of finding a home for the stone (show: finding a home for the stone) to verify our judgment! 1, 2 and 3 groups found No.2 rock, 4, 5 and 6 groups found No.4 rock, 7, 8 and 9 groups found No.5 rock,1,1,12 groups found No.6 rock. Do you know the name of this stone? Let's start here! Please follow the arrows that match the rock characteristics. (Show the bubble chart step by step and introduce it while clicking) Have you all found a home? Is anyone lost? This shows that our appraisal just now is correct. We know these rocks. Now let's play a guessing game. Rules of the game: Describe the obvious features of 1 or 2 rocks (no more than 2 rocks), and let other students guess the name of this rock at once. If everyone can guess, your description is successful! (Applause) Who will describe it? Who will guess? 6. Summary of the conversation (2 points) 1. Stones can be seen everywhere in life. Please pay attention and identify what rocks they belong to. 2. How are these different rocks formed? Please read the book on the genesis of rocks on page 8 1 carefully after class. Blackboard design: touch particle color recognition (magnifying glass) stripes? 6? 7? 6? 7 Listen to several kinds of rocks and rocks (dilute hydrochloric acid drops) 5 Make the sky of exploration bluer-the experience of teaching "Understanding several kinds of common rocks" 1. Skillfully paving stones-constructing structured materials is the premise of effective exploration. First, in science teaching in primary schools, active materials are the basis and key for students to learn science. Teachers' careful design, selection and provision of structured materials are the basis of inquiry teaching and the premise for students to participate in practice and exploration independently. Therefore, according to the requirements of teaching materials, the teaching objectives of this course and the age characteristics of students, I carefully selected six typical, enlightening and operable rocks. For example, choose slate, limestone and shale. According to the textbook, there is a crisp sound when you hit slate, but there is no bang when you hit shale. After repeated practice, it is found that there is no obvious difference between the sounds made by hitting slate and shale, so slate and shale can only be chosen. If slate and limestone are chosen, the two kinds of rocks are similar in particle color, particle thickness and particle structure, which will cause a vague feeling in the vision, which will further urge students to explore their differences carefully. When choosing limestone, I found that there are many white impurities on many limestone, which look like white stripes. When trying to teach, students often describe these impurities as the distinctive features of limestone, so I carefully selected each rock. Secondly, when students discuss an interesting question in depth, they should ensure that they have enough time to explore. For example, during the trial teaching, students were provided with bottles and droppers of dilute hydrochloric acid at the beginning of the observation experiment. The students were so interested in this new thing that they forgot all the observation tasks assigned by the teacher. In addition, I have been worried that I can't finish the "task" and give the students 12 minutes to observe six rocks. Ask the students to describe that this link is chaotic. So, I adjusted the number of stones, asked students to choose four stone heads for careful observation, and left time for students to communicate, sort out, think and improve the collected facts. Therefore, the students described the rocks they chose well and achieved the expected results. Second, blending and integration-being good at capturing dynamic generation is the key to effective exploration. The purpose of carefully selecting active materials is to better serve classroom teaching and students, so that they can carry out scientific inquiry effectively. How to make these structural materials play their greatest role? This is closely related to whether teachers can capture the valuable information generated dynamically in the classroom in time and blend flexibly. Before the trial teaching, it is unknown to what extent students have mastered rocks and methods of observing rocks, so the guidance on methods and contents of observing rocks is blind. As a result, it took a lot of time, but the effect was not great. Students are still puzzled by many new terms and concepts such as bedding, stripes and texture. Therefore, it is more difficult for fourth-grade students to observe and record rock characteristics in a limited time than to ascend to heaven! To solve this problem, my first thought is the source problem-how many preconceptions do our students have about rocks and the methods of observing them? After studying the teaching materials and reference materials repeatedly, it is found that the fourth unit can be divided into two parts: rocks and minerals. The first three classes mainly explore rocks, the last three classes mainly explore minerals, and the first three classes explore rocks, which are interrelated and gradually deepened. The first lesson, "All kinds of rocks", is to let students observe rocks by various sensory methods according to their own life experience and existing knowledge level, obtain information on the surface of rocks and some external characteristics of rocks, and classify rocks simply according to some characteristics. The second lesson "Understanding Several Common Rocks" is based on students' learning to observe the external characteristics of rocks in various ways, observing the structure and particles of rocks in depth, preliminarily understanding the remarkable characteristics of several common rocks, and identifying rocks according to these remarkable characteristics, and preliminarily understanding the particles that make up rocks, thus laying a learning foundation for the third lesson "Composition of rocks". In the third class, students can analyze the particles that make up rocks, that is, the minerals that make up rocks. Based on the above understanding, I made a brand-new design for the teaching plan. The current teaching design is as follows: first, try to teach the first lesson in class, because this is the basic premise of the second lesson teaching. In the first part, we observe the deletion of rocks, because it belongs to the first lesson. This lesson mainly focuses on two inquiry activities: First, students explore independently and further observe rocks. On the basis of observing, recording and describing the characteristics of rocks, the remarkable characteristics of rocks are further summarized and refined. The second is to identify rocks, and analyze, judge and identify the types of rocks according to their remarkable characteristics and with the help of data. In guided observation 6, I focused on guiding observation of rock particles and dropping dilute hydrochloric acid to see the reaction. For the concepts that are difficult to understand, I supplemented the perceptual pictures of images to reduce the cognitive difficulty of students, and made appropriate adjustments to the observation record table, using the method of "√" to reduce the difficulty of students' recording. When the students observed the rocks, they found that the order in which the students observed the six rocks was chaotic and could not go deep. Coupled with the premature distribution of dilute hydrochloric acid, students are particularly keen on learning new things, and the whole inquiry activity is time-consuming and inefficient. So, I asked the students to observe the rocks for 7 minutes and then collect dilute hydrochloric acid. In the warm reminder, I particularly emphasized the independent choice of four stone heads I like, division of labor and cooperation, and observation one by one. In this way, every student can observe the rock attentively and carefully. In the report, let students describe the characteristics of rocks with the help of observation records, then give students time to sort out and describe them in their own words, and then show two rocks that look very similar and compare their similarities and differences. After learning the description of rock characteristics by rock experts, let students extract the remarkable characteristics of each rock to identify rocks, so as to be gradual and natural. Students' description of rocks is in place, which is the best interpretation of students' effective exploration! Second, dynamic regulation is the key to effective exploration. Third, stimulating interest in games is a magic weapon for effective exploration. Interest is the best teacher. If we can turn boring scientific knowledge into a game that students like, we will get twice the result with half the effort. Entertainment TV often tells about this program. I introduce this activity into the classroom as a form of pre-class game, and guess my classmates through students' descriptions, so that students can deeply realize that only by being good at grasping the remarkable characteristics of characters and describing them can they succeed. It also laid a good foundation for talking about speculation in the later rock teaching. It's killing two birds with one stone! In the lead-in session, six stones are made into cartoon images, so that the protagonist who can talk and guess today can appear and cut into the theme, which stimulates students' interest in learning and exploring. In the process of identifying the observation results according to the rock particles, the bubble chart of bubble cake is dazzling and complicated, so it is difficult for students to sort out the clue. Compared with the serious and dedicated energy when exploring rock characteristics, the enthusiasm has already drifted to the outside world, so it is only empty talk for students to identify the results with their heart. So, I changed this link into a game of finding a home for the rock with both hands, and the students' enthusiasm for exploration was activated again. They lifted the stones one by one, and followed the arrows on the big screen intently to find the stone's home. Then ask the students, have you found a home for the stone? When I saw the excitement of the students who found a home for rocks, I knew that not only did the students further deepen their understanding of the obvious characteristics of rocks, but more importantly, they experienced the process of carefully identifying rocks. After the students had a comprehensive understanding of rocks, I designed a guessing session. Clear rules of the game actually emphasize the importance of grasping the distinctive features of rocks to describe them. The students described are full of interest, and the students who guessed are full of interest. Students learn easily and learn solidly, so why not? Content: First of all, because the observation content is brand new, and there are many new concepts that are difficult to distinguish and understand, such as stratification, texture, stripes, the division of particle thickness, the distinction between dense particles and loose particles, etc., which need to be explained in detail. Secondly, the new observation method needs guidance, which is difficult for students to understand, and then it is implemented in rock observation. The teacher's guidance is required to be meticulous, time-saving and efficient. I tried to implement picture-assisted teaching. Because of the need to complete the instruction task quickly, the picture is too small for students to understand after browsing. In operation, students are still at a loss about bedding, stripes and pores. The first trial teaching 12 minutes overtime should make students clear: what method did I use to observe rocks? What characteristics of rocks have I observed? How can I describe the characteristics of rocks? These three problems are logically related. The first sentence emphasizes the cultivation of inquiry methods in science class, and guides students to observe rocks comprehensively by touching, smelling and tapping. The second sentence requires students to think about the results of observation in combination with their own feelings and experiences; The third sentence requires students to choose appropriate words to record and describe the characteristics of rocks on the basis of observation. Remarks: In the activity of "observing and describing the characteristics of rocks", why should we pay so much attention to how students describe them? Because description can promote students' thinking, deepen observation results, better grasp the characteristics of rocks and compare the differences of various rocks. This is not only the need of observation itself, but also the cultivation of students' thinking ability and scientific attitude. In the bubble diagram on page 65 of the textbook, the circles around it are reserved for students to fill in, and students are required to fill in words describing the characteristics of rocks. Words describing rocks can be shiny or dim; Smooth and rough; Heavy and light; Transparency, opacity, etc. Through this part of teaching, I hope to encourage students to observe repeatedly and come up with more and more suitable words. "Look again, can you find something new?" This means that students should pay attention to other people's descriptions in communication activities, which may inspire themselves in the content and methods of observation and produce the desire to observe again. In the activities of re-observation, learning other people's observation methods may lead to new discoveries. Limestone: generally light gray, dark gray, etc. Pure limestone is colorless or white. The main component is calcite, sometimes with a small amount of dolomite, often mixed with chronological, feldspar, mica and clay minerals. Limestone is brittle, has low hardness, and is easily scratched by iron. It will blister violently when it meets 5% dilute hydrochloric acid, so it is easy to distinguish. Conglomerate: It is different from sandstone in that the particles are coarse and the sediment particles are larger than 2mm, so it is called conglomerate. Fresh colors-matrices are mostly white, yellow and gray. Weathered color-yellow-brown slate: the particles are very fine, equal in size and color, and closely combined. Sandstone: uniform particles, fine texture and loose structure. Granite: usually gray, red, hard or grayish red. Among them, those with uniform texture, fine texture and white color, also known as white marble, joined the work in 1996, with a bachelor's degree and a primary school teacher. Since teaching science for five years, she has paid attention to the research of effective inquiry in classroom teaching. At present, she is a science teacher in the primary school affiliated to Taizhou University. eight