1. Perceive and understand the significance of kilometers in specific life situations; Establish the concept of 1km in rich operation activities, and know that1km =1000 m. It can solve some practical problems about kilometers and experience the application value of kilometers.
2. In the practical activities before and after class, learn to accumulate and find information, constantly experience the close relationship between mathematics and life, enhance the interest in learning mathematics and confidence in learning mathematics well, and gain positive mathematics learning emotions and the ability to solve practical problems.
Emphasis and difficulty in teaching:
Experience and understand the actual length of kilometers. Establish the concept of 1 km.
Teaching resources: courseware, physical projection.
Teaching process:
First, interactive dialogue-generating the concept of "km"
1. Question: What commonly used units of length do we know? Express 1 cm and 1 m in the way you like. (Students indicate 1cm, 1m by gestures, meters or the length of surrounding objects).
2. Fill in the blanks: Fill in the appropriate length units for the following objects.
Rubber length 4 () The length of the school track is 250 () The road from Anzhen to Wuxi is about 14 ().
Teacher: The length of the highway from Anzhen to Wuxi, why do we use kilometers as the unit?
Students discuss and communicate with the whole class.
3. Description: Calculate the distance or measure the length of railways, highways and rivers, and the unit is usually "kilometers". Introduce the symbol of kilometers. (blackboard writing: Km Km) Learn how to read km.
4. For example: Where have you seen or heard of kilometers? (The camera shows pictures: milestones of railways and highways, speed limit signs on highways, line segment scales on maps of administrative districts of Hong Kong, etc. Do you know the meaning of each picture?
Second, teachers and students explore-construct the concept of "1 km"
1, dynamic demonstration process-preliminary experience of propulsion rate between kilometers and meters.
(1) Guess: Kilometers are widely used in life, so how long is 1 kilometer? Guess!
(2) Observation: How long is 1 km? Please carefully observe the process of highway length and write down what you see.
Multimedia visual demonstration: Every time100m is measured, "100m", "200m", "300m" and "900m" will be enlarged and displayed. Finally, with the music, "100m" will become "1km".
(3) Question: What do you know?
(1 km = 1000 m, 1000 m includes10/00 m). )
(4) Summary: 1000m = 1km. Guide the students to read this formula, and pay attention to the need to pause between the previous number and the latter unit.
2. Recall the activities before class-further experience the concept of "1 km".
(1) Let's do the math: We have measured the length of a track in our school before class. The (250m) track is 1 km, and the track of the 250m track is 1 km.
(2) Estimate: Before class, everyone has been invited to take a walk in the playground. How many steps did you take and how many minutes did it take? Can you estimate how many steps there are in 1 km? How many minutes does it take to walk 1 km?
(3) Say: Do you think 1 km is long? Free communication.
(4) Find out: Where is the school-to-community 1 km? Can you still find a place 1 km away from your life?
Third, the application of life-activate the knowledge of "kilometers"
1, further understanding of "1 km"
(1) Do the "Want to Do" Question 1
Let the students draw the length of 1 km independently.
The communication from where to where is 1 km, please let the rest of the students participate in the evaluation.
(2) Do the second question "Think about it and do it"
Guide the students to say what you know from the pictures and what you want.
Practice independently and organize communication. Emphasize the conversion method of meters and kilometers.
2. Further understand "1km = 1000m"
Do "think and do" question 3.
Students do it independently.
Organize exchanges and talk about your own ideas.
3. Further clarify various length units.
Do "think and do" question 4.
Students discuss what length units are suitable.
Organize communication.
4, comprehensive application of new knowledge to solve practical problems
(1) Do "Think, Do" Question 5
Ask the students to compare the lengths of rivers directly.
Said that each river is about several kilometers.
(2) Do "Want to Do" Question 6.
Question 1 Ask students to calculate directly. Questions 2 and 3 organize students to discuss and propose solutions to the problems.
Exchange ideas.
Fourth, summarize and extend-expand the knowledge of "kilometers"
1, Question: What new knowledge did you learn today and what did you learn before? What's the use of studying?
2, the actual work:
After class, investigate the average speed of various vehicles and the distance of each road section, and record the investigation results.
Vehicle name
automobile
train
steamboat
plane
General speed
A section of a road or railway.
Travel distance
Anzhen-Wuxi
Wuxi-Shanghai