Teaching design of "length unit" in the first volume of senior two mathematics
Teaching objectives:
Knowledge points:
1. Let students experience the process of forming length units and understand the necessity of unifying length units.
2. Through activities, make students know the length unit centimeter, initially establish the concept of 1cm, and initially learn to measure the length of an object with a scale.
3. Cultivate students' estimation consciousness and ability.
Ability point:
Cultivate students' ability of observation and operation.
Moral education point:
Make students develop serious and serious study habits.
Teaching focus:
Through the activities, let the students know the length unit of centimeters, and learn to measure the length of objects with a scale.
Teaching difficulties:
The concept of length of 1 cm is initially established to cultivate students' estimation consciousness and ability.
Teaching mode:
? Independent investigation? Teaching mode.
Teaching aid preparation:
All kinds of rulers, coins, paper clips, cubes with a length of 1 cm, etc.
Teaching process:
First, create a situation:
Teacher: Mom needs to buy an elastic band. How long will it take? The teacher measured it, which is as long as the stick on your desk. Please select a physical object for each group to measure.
Students report the results.
Q: It's strange that elastic belt with the same length has different results.
Teacher: If we want to get a unified result, what tools should we use best?
Health: Ruler.
Second, independent inquiry:
1, I know 1 cm.
Take out a ruler and have a look. What did you find?
Students observe and report.
First, the number, read in order. Q: What is the leftmost position? What does the zero on the ruler mean? This is called zero scale.
B, lines, long and short, are called tick marks.
C, letters? cm？ , which stands for centimeter, is a commonly used unit of length.
How long is a centimeter? (The length between scale 0 and scale 1 on the scale is 1 cm. )
Find 1 cm on your ruler. Which paragraph is 1 cm? What did you find? (each grid is 1 cm)
Find and compare what other objects around us are about 1 cm in length.
Hand-painted length of 1 cm. Close your eyes and think about how long 1 cm is.
2. Know a few centimeters.
Teacher: We know how long 1 cm is, and how long are those 2cm and 3cm?
Q: How many centimeters are two 1cm? How many 1 cm are there in 4 cm? Can you point out the 6 cm part of the ruler?
3. Use centimeters.
Hold up the blue note and estimate how many centimeters it is.
Measure it with a ruler. Fill it in the book.
Measure the length of the elastic band.
Third, expand the application:
1. Is the following measurement method correct? Explain why.
(1) is not aligned with the 0 tick mark.
(2) correct.
(3) measurement is not started from zero scale.
2. What should I do if the front of the ruler is broken and I can't see the 0 scale line?
3. The amount of group cooperation defines the length of the object.
The teacher wants to measure the length of a wrist. It is inconvenient to measure with a ruler. Do you have a good method? (Introduce all kinds of rulers)
5. Choose a ruler and measure the object you are interested in.
Collect information after class: What other units of length do you know?
Teaching Design of Length Units in the Second Grade of Mathematics (Part Two)
Teaching objectives:
1. Through games, observation, practice and other activities, let students know the line segment, measure the line segment with a ruler, and draw the whole centimeter line segment as required.
2. Let students feel the characteristics of line segments vividly and intuitively in operation.
3. Try to help and learn from classmates, and correctly explain the knowledge found and the method and process of solving problems in language.
4. Experience the connection between mathematics and life, and feel and appreciate the concise beauty of graphics in mathematics.
Target resolution:
Create interesting game situations and let students experience that the line segment is straight. In a series of hands-on operations of finding, touching and measuring, we can further experience that the line segment is straight, and we can measure the length characteristics, paving the way for the following line segment drawing. ? I'm a little designer? Links fully arouse students' creative desire, organically combine what they have learned with graphics, and feel the beauty of mathematics, so that they want to learn and enjoy learning.
Teaching emphases and difficulties:
Feel the characteristics of the line segment, measure and draw a complete centimeter line segment with a centimeter ruler.
Teaching preparation:
In the courseware, each student has a 30 cm rope, a ruler (centimeter ruler) and so on.
Teaching process:
First, create situations and introduce games.
(1) game
Name: playing with rope.
Rule: Make a rope into different shapes.
Student report: Tell the shape and characteristics of the rope. If the students pose, they can directly lead into the new lesson. If not, the teacher can directly show the straight one, indicating that it takes the shortest time and is the most concise. )
Writing on the blackboard: straight
(3) Introducing new courses. A rope so tight can be regarded as a segment. Today, in this class, let's get to know line segments together. (blackboard writing topic: understanding line segments)
(4) Students pull it and tell me what it is after straightening it. (line segment)
Emphasize that the straight line segment between hands is regarded as a line segment.
(5) blackboard writing:
Design intention: Children in Grade Two are young and slow in concentration. It is not difficult to set up a rope throwing game before class, which can quickly attract students' attention to the class and cultivate their awareness of active participation. Through the process of swinging and pulling, let students perceive the difference between curve and straight line, and visually realize that the line segment is straight. Emphasize? As, as? Pay attention to the scientificity and rigor of mathematical language, so that students can imperceptibly perceive that a line segment has two endpoints.
Second, create activities and explore new knowledge
(1) Touch: Find the line segment in life.
1. Work in groups, find and touch what other edges in life can be regarded as line segments?
2. Report to the class. Pay attention to correct the mistakes in students' oral narration and ensure the accuracy of the narration. )
3. Courseware appears on the blackboard, desk and book in turn. Where are their line segments?
4. Students answer and demonstrate on the computer. (Select Line Segment)
5. Teacher's summary: The blackboard edge, the table edge and the book edge can all be regarded as line segments.
6. Appreciate the line segments in life. (Courseware demonstration)
Design intention: Learn mathematics in life, and let students discover that mathematics is inseparable from real life through a series of activities such as searching and touching. Computer demonstration extracts line segments from physical objects, which further deepens the understanding that line segments are straight, helps students to establish a preliminary mathematical model from intuitive things to abstract mathematical concepts, and tries to perceive the world from a mathematical perspective. Appreciation activities will stimulate students' enthusiasm for learning, so as to enter the next stage of learning and exploration.
(2) Survey: You can measure the length of a line segment.
1. Show me three line segments on the fifth page of this book. They are all line segments. Find out what they have in common
2. Group inquiry and classroom communication.
3. Teacher's blackboard writing: All are straight, and the length can be measured.
You have a good eye. Since line segments can be measured, please measure the length of these three line segments.
5. Complete independently and communicate in groups.
6. Report to the class. Let the students dictate the method and process of quantity, and talk about what needs attention.
7. Teacher's summary: When measuring a line segment, what is the end point and ruler of the line segment? 0? Alignment of tick marks. If the other end of the line segment is opposite to the number, what is the length of the line segment?
Design intention: All students are encouraged to participate in autonomous learning through group cooperation, so that every student can try to express his own thoughts and internalize the visually intuitive line segments into abstract concepts. The students have just finished learning the measurement of objects, and use the measurement line segment to pave the way for drawing the line segment below.
(3) I am a small designer: draw line segments.
1. Design a 3 cm line segment on the paper. See who designs more styles.
2. Show students' works and praise the designed students. Let them talk about how it was painted.
3. After the teacher explained the demonstration, the teacher summarized it.
Reflections on the teaching of length units
"Length unit" has opened the prelude of mathematics teaching in grade two, which is the learning content that children are interested in, because a lot of knowledge comes from children's own experience and their closely related lives. After learning the unit of length, many children think math is very interesting, very fun,,,
Indeed, it seems that everyone has been playing these classes. They measure textbooks and pencil boxes with coins, thumbtacks and paper clips, measure their physical data such as step size and length with a ruler, and measure the length and width of the classroom with a tape measure. There are also a lot of activities such as estimation and observation. Children are playing and studying in middle school. How happy I am!
Actually, do you understand? Rice? 、? Centimeter? It is not easy to establish the representation of length. In order to make children learn knowledge easily and effectively, build? Rice? And then what? Centimeter? Appearance, the rational use of knowledge, the materials we present and the learning activities organized should be realistic and situational.
Reflecting on these children's favorite classes, I think the first thing is the reasonable arrangement of teaching materials. In the past, textbooks often told students that the length of an object can be measured with a ruler, and both meters and centimeters are lengths, so as to establish a correct representation and develop the concept of space. When the new textbook presents the length units of centimeters and meters, it is to let students experience the process of unifying the length units through sufficient activities: to let students know the source of knowledge and feel the necessity of unifying the length units, and at the same time, to introduce the small square of 1 cm as the unified unit length, but it is inconvenient to take the square every time, which leads to the understanding of rulers, centimeters and meters and the progressive teaching between them. The arrangement of teaching materials can restore the lively construction process of mathematics according to the characteristics of children's learning mathematics, so that students can experience similar creative processes and use their own activities to construct an understanding of human existing mathematical knowledge.
The second is to organize reasonable learning activities, which are embodied in the following aspects.
First, establish the initial appearance of length units in the activity.
It is the nature of primary school students to love to play. If we can respect children's nature, effectively create activity plots in teaching, guide students to learn in activities, and communicate the relationship between students' emotional world and book world, teaching will achieve unexpected results. As mentioned above, children's interest in learning is always high, and these activities are of great significance for them to establish a correct appearance and form a good sense of numbers.
Those who have seen the teaching design of the length unit in the second grade of mathematics also look at:
1. Teaching design of wide-angle arrangement of mathematics in the first volume of second grade mathematics
2. Teaching plan of 7 multiplication formula in senior two mathematics.
3. Teaching design of mixed operation of mathematics in grade two.
4. Summary of mathematics teaching in the second grade of primary school
5. Teaching design of understanding numbers within 10,000 in second grade mathematics.