1. The international unit of length is meters, and other units are kilometers, decimeters, centimeters, fine meters, microns and nanometers. Conversion relationship between various units.
2. You should know that the tool for measuring the length is the scale, so you can measure the length correctly with the scale.
3. Be able to read the measured results correctly and know that the measured values are composed of accurate values and estimated values.
4. Know what is wrong and what is wrong, and distinguish between mistakes and mistakes.
capability goal
1. Cultivate observation ability: observe figures and images, and understand that the length of visual judgment is different from the actual measurement; By observing the scale, we can know its range, minimum scale and zero score line.
2. Cultivate thinking ability: learn the general method of conversion through unit conversion.
Moral education goal
Develop a good habit of being careful and meticulous, such as taking the average value of many measurements to reduce errors.
Textbook analysis
First of all, by letting students observe the picture and estimate the time of 1 minute, the textbook realizes that people's feelings are not reliable, which leads to the importance of actual measurement with measuring tools. This paper lists the measuring tools familiar to students, and points out that length measurement is the most basic measurement, and the scale is the most commonly used measuring tool. The textbook uses pictures to help students analyze how to measure the length correctly with the scale. The textbook requires that we should pay attention to the observation link in teaching. For the "unit of length", two scenes in daily life are provided, so that students can form the concept of general length in connection with life. In the content of "errors", the textbook analyzes the causes of errors, the differences between them and the methods to reduce them in easy-to-understand language.
Teaching suggestion
As for the measurement part, because students lack the experience of quantitative research on natural phenomena and have insufficient understanding of the importance of measurement, they should be guided to observe two examples in the textbook. Conditional schools can also use other examples to make students realize the limitations of using sensory organs to judge, and at the same time improve students' interest in learning, so that students can conclude that "feelings are not always reliable and need to be measured". On this basis, teachers can further combine the reality and explain in production and life.
Regarding the unit of length, we should focus on forming the specific concept of length, so we should show pictures, images and some video materials about length in teaching, and pay attention to let students move and practice by themselves in teaching methods.
Regarding the correct use of the balance, first observe the zero point, range and minimum scale of the balance, and inform other measuring tools that there are similar problems, thus forming the concept of "the common law of different things" for students. On this basis, the correct method of measuring length with scale is obtained through observation. Teachers can organize discussion groups in classroom teaching, and then guide students to think hard and understand, and analyze the difference between correct and wrong measurement methods.
About the correct record of measurement results, we should indicate the unit, which should be further consolidated in future study, and remind students to pay attention to this problem. On the issue of correct reading, we should make clear the steps of obtaining reading, so that students can consolidate and form study habits with practice, rather than let students understand the details and principles.
Regarding the teaching of mistakes, we should make clear the difference between mistakes and mistakes and know the methods to reduce them. The specific application of taking the average value of multiple measurements will only be applied to the physical measurement of resistance in grade three.
Example of instructional design
The first section length measurement error
The subject or problem of study.
Length measurement error
Analysis of key and difficult points
Knowing the unit of length is a difficult point for the exponential expression of length progress rate, but it can't be too demanding, forming a new difficulty. You can use the scale correctly and judge whether it is right or wrong. You can record the measurement results correctly and estimate one bit based on the exact value. Error is a difficult point, so don't explain it too deeply.
Teaching process design
1, launch new courses.
Schools with good conditions can organize students to observe cartoons or pictures, while schools with ordinary conditions can observe 1- 1 and 1-2 in textbooks, so that students can draw the conclusion that "the feeling is not necessarily reliable and needs actual measurement", thus leading to the important position of measurement in physics.
Explain the decisive role of measurement in some aspects, and pay attention to combining with practice: launching an artificial satellite, regardless of whether the satellite is moving normally or not, requires constant various measurements, and this measurement requires high accuracy.
2. New teaching: units of measurement and length
Length measurement is the most basic measurement, and measurement should have standards, so length has units, which can be extended to all physical quantities. Introduce the length unit.
In order to make students establish the concept of length unit size in teaching, schools with better conditions can help students imagine some length values with animation (the scale of nature), graphics and images. On the basis of students' full observation, let the students fully move with the reality and find out about 1 meter, 1 decimeter, 1 cm and 65438+ on their own bodies.
Students practice converting units, judging numerical units and consolidating their knowledge. 3. New teaching: measure the length with a ruler.
The common tool for measuring length is the scale. Observe the scale and tell the position, range and minimum scale of the zero scale line of your scale. Then observe some figures to explain the zero scale line, range and minimum scale of these scales.
Students can observe graphs and image data, or observe 1-5, 1-6 and 1-7 in textbooks, and organize students to discuss and summarize the correct method of using the scale: the scale line of the scale is close to the measured part of the measured object, and when the zero scale line is worn, it can start from other scale lines; When observing the measurement results, the line of sight should be perpendicular to the ruler surface. At the same time, students should discuss the problems when they don't use it in the right way.
Note the unit when recording the results, and estimate one person after reading the accurate value. The teacher read the length of the building block with the board diagram: the exact value is 2cm, and then estimate that a person is about 0.2cm, so the length of the building block is 2.2cm. ..
On this basis, add the millimeter line, at this time the minimum scale of the scale is millimeter, and then read out the length of the wood block. By comparing these two values, we can see that the results obtained by measuring the same object with scales with different accuracy are different. We can show more questions and consolidate students' correct reading. We should pay attention to cultivating students' study habits in teaching.
4. New teaching: misunderstanding
For the teaching of "errors", we only grasp three questions: what is an error and how it comes about; The difference between error and error; Methods to reduce errors. These three questions can be discussed by students.
Because the estimated values are different, different scales are different, and some environmental factors affect the measuring tools, resulting in errors, so the errors can not be absolutely avoided. We call the difference between the measured value and the real value an error. Error is the error in measurement method, which can be corrected in measurement. This is the difference between them. The way to reduce the error is to choose a precise measuring instrument and take the average value of many measurements.
blackboard-writing design
Investigation activities
This question refers to some units about length.
Activities are organized in groups.
Teacher guidance
1, which provides some historical data about the length.
2. Different countries have different units of length.
3, the length of the international system of units, unit conversion.
evaluate
1, richness of data sources
2. The content of auspicious degree.
3. The richness of the data itself
Teaching plan template of eighth grade physics "measuring length with scale to do experiments"
Teaching objectives
Knowledge goal:
1, the length will be measured with a ruler.
2, can correctly record the experimental data.
Ability goal:
1, observation and experimental ability: a preliminary understanding of the basic process of physical experiments; Learn to measure the length of an object with a ruler.
2. Application ability: solving problems encountered in experimental operation; Think about the problems in the actual phenomenon.
Emotional goals:
1, educate students to care for instruments and equipment, and cultivate the moral character of caring for public finances.
2. Good experimental habits.
3. Record the data truthfully and cultivate the spirit of seeking truth from facts.
Textbook analysis
Students should first observe the scale used to know the position, range and minimum scale of the zero scale line. Students should develop good measuring habits and observe clearly before using measuring instruments. The textbook does not require too much to reduce the error, nor does it require students to measure the average value many times in the experiment. Therefore, when measuring the length and width of textbooks and exercise books, only pay attention to estimating one place, and indicate the unit when recording the results.
When measuring thin copper wire, we should emphasize tight winding. The measured length divided by the number of turns is the diameter of the thin copper wire. When measuring the diameter of coins, students are required to measure with a scale and a triangle.
It is mainly to make students learn by doing, emphasizing the process of experiment and thinking.
Teaching suggestion
This part is the first time for students to do experiments. They should abide by the rules of the laboratory, pay attention to the problems in doing experiments, develop a serious attitude towards experiments, respect the truth when recording the results, do not change the data at will, and have certain analytical ability for the results.
Example of instructional design
The second experiment: measure the length with a scale.
Subject experiment: measuring length with scale
The analysis of key and difficult points will use a ruler to measure the length, read correctly and measure the length with special methods.
Teaching process design
1, launch new courses.
This paper introduces the rules of the laboratory, and explains that physical experiments should pay attention to the spirit of seeking truth from facts and have a scientific experimental attitude.
2. Carry out the experiment according to the experimental steps.
Observe whether the zero scale line of the scale is worn; What is its scope; What is the minimum size? According to the content of the last section, let the students describe the correct use of the scale and the rules of reading.
Measure the length and width of textbooks and exercise books, record the data in the table and write down the units. When reading, one digit should be estimated after the accurate value.
When measuring the diameter of thin copper wire, students should pay attention to winding the iron wire tightly on the pencil, measure the total length, and divide it by the number of turns to get the diameter of thin copper wire. After recording the data, ask questions for students to think about: how to measure the thickness of a piece of paper, and then sum up that this method is measured by accumulation method. This method will be used in the future and is often used in actual production and life.
When students measure the diameter of coins with scales and triangles, they should be made to think and see if they can come up with a method. Then, they should use charts to help explain, and after recording, they should be inspired to think further about how to measure the height of the cone and the length of irregular objects. Conditional schools can use animation to show, or pictures to help students imagine, so that students can draw inferences.
Teaching plan template for eighth grade physical and mechanical sports
Teaching objectives
Knowledge goal:
1, know the mechanical movement
2. Understand the relativity of reference objects, motion and stillness.
3. Know the uniform linear motion.
Ability goal:
1, observation and experimental ability: an example of observing the mechanical movement of objects from life.
2. Thinking ability: judge and analyze the mechanical movement, and analyze the moving and static situation with the knowledge of reference objects.
3. Ability to solve practical problems: Explain and judge the movement phenomena in nature.
Emotional goals:
1, the education of dialectical materialism movement view.
2. Cultivate students' awareness of science and technology, love and admire science.
3. Infiltrate patriotism education through the teaching of geosynchronous satellites.
Textbook analysis
The textbook leads to the problem of object motion from examples, and calls the change of object position mechanical motion, and then extends it to examples in nature. The concept of reference is also derived from examples. Combining with the actual analysis of examples in life and nature, students are required to judge the movement of objects and analyze the selected reference from the movement. On this basis, the perceptual analysis of uniform linear motion is carried out, and a method of physics research is explained, that is, starting with simple problems and step by step.
Teaching suggestion
Try not to deepen the content in the textbook, but should combine the reality more, improve students' autonomous learning ability and practice learning habits, and deepen their understanding of some physics learning methods.
Introduce new lessons through discussion, guide students to think about problems, and directly define mechanical motion in physics. For the study of the relativity of motion and static, students should ask questions and discuss them, which leads to the concept of reference object. Students should list examples, students should analyze, teachers can evaluate, and finally summarize the general analysis methods. Appropriate media materials can be used in the teaching of this content, such as the supporting video of the textbook "Relativity of Motion".
The teaching of uniform linear motion, observing and analyzing the examples in textbooks, shows that this is an approximate uniform linear motion. Students should think about the approximate uniform linear motion in life and nature, deepen their perceptual knowledge of uniform linear motion, and give a definition on this basis. In the definition, it is only necessary to make it clear that the speed is constant, and it is not appropriate to introduce the concept of speed.
Example of instructional design
Teaching unit analysis
This section focuses on the teaching of reference objects, which requires that the selected reference objects can be analyzed through the movement, and the movement of objects can be judged by knowing the reference objects.
Teaching process analysis
First, mechanical movement.
This paper discusses the introduction of new courses, the contents of textbooks for students to read and the reference materials provided. The reading question is: What is mechanical movement? Illustrate the mechanical movement in nature with examples; Whether desks and houses do mechanical exercise, and why; Can you give an example of absolute immobility?
The examples given by students can be analyzed, and attention should be paid to the following problems: we call the change of object position mechanical motion; The universe is moving, and everything in the universe is moving.
Second, the reference object
This paper expounds the explanation of some phenomena in daily life, and further introduces the concept of reference object. The problems that should be paid attention to when explaining are as follows: Through the analysis of examples, it shows that different people have different descriptions of sports, because they choose different standards for sports description, and we call the objects selected as standards as reference objects.
Students illustrate the movement of the same object when choosing different reference objects, and deeply analyze the movement characteristics when choosing other reference objects.
Two kinds of examples are analyzed: knowing the reference object and judging the motion of the object; Judging the selected reference object according to the described motion situation. Teachers can analyze the specific situation of students, and students' creativity can also be brought into play. Students can form groups, design problems by themselves, discuss them by themselves and evaluate them by teachers. Provide some reference examples: what is the reference object of the sentence "Sunset every day", "Geosynchronous satellite is always stationary over the earth, what is the reference object", "The sun is the reference object, and what is the movement of geosynchronous communication satellite? What are the quotations from the first half and the second half of the lyrics, "Small bamboo rafts are in the middle reaches of the river and walking on both sides of the towering green mountains"?
Third, uniform linear motion.
By observing some examples, we can provide videos and video files and pictures to make students think about the characteristics of these actions. For students with good foundation, we can find commonness and summarize the characteristics of uniform linear motion. When explaining, we should pay attention to the constant speed, instead of introducing the concept of speed, so that students can form a perceptual understanding of uniform speed, and explain that uniform linear motion is the simplest mechanical motion, and physical research problems start with the simplest problems.
In order to think about the problems in the discussion, students can be provided with pictures and materials in natural science. For students with a good foundation, you can arrange to consult the preview content of the materials before class and ask about the relevant information of satellite launch and satellite movement in China.