Understanding angle

Source of knowledge point

□ Subject: Primary Mathematics □ Grade: Grade 2 □ Textbook Version: Beijing Normal University Edition

□ Chapter: Unit 6, First Class, Understanding the Angle of Graphics

Recording tools and methods

Screen recording software Camtasia Studio V6.0.2 mixed recording.

Design concept

1, this lesson is guided by the story written by Xiao Hui at school, which arouses students' interest in diagonal understanding;

2. Through the picture demonstration and introduction of multimedia courseware, students can understand the composition and characteristics of angles;

Teaching design

Internal capacity

Academic goal

1, get a preliminary understanding of the angle and know the names of each part of the angle.

Knowing the size of the angle, we will compare the size of the angle.

Emphasis and difficulty in teaching

Key points: Help students form a correct representation of angle and initially establish the concept of angle.

Difficulty: the exploration angle is related to the size of the mouth opening on both sides, but not to the length of both sides.

teaching process

First, create situations and introduce new knowledge.

Teacher: Do you like watching cartoons, little friend? Today, the teacher brings you a story about Pleasant Goat and Big Big Wolf-Little Grey goes to school!

In the morning, Grey Grey happily came to the school in Yangcun, but Pleasant Goat said angrily to Grey Grey, Yesterday, I heard you talking with Grey Wolf about horns. Do you want to play with our horn? Gregray cried in grievance. At this time, the village chief Slow Sheep came. You all misunderstood gray. You don't usually study hard. It's terrible to have no education! They are not talking about angles, but "angles" in mathematical figures. Now, please come with me to know the corner.

2. Understanding angle

1, the name of each part of the cognitive perspective.

Look for angles from things in real life, then abstract them from the concrete to the angle, observe them carefully, and then feel the characteristics of each part of the angle, with sharp vertices and smooth edges. The dominant angle has a vertex and two sides.

2. The size of the angle has nothing to do with the length of the side, but only with the opening of the angle.

Use animation process: a pair of scissors cut both sides of the corner short and ask questions: Is this corner smaller?

It is easy to see that the angle has not decreased, because the size of the angle has nothing to do with the length of the side, but only with the size of the mouth. The bigger the mouth, the bigger the angle; The smaller the mouth, the smaller the angle.

3. compare it.

One-to-one comparison, we compare two angles with the same mouth and different sides. Once again, we are familiar with the result that as long as the mouths are the same, the length of the sides does not affect the size of the two corners. Comparing one and two, we compare an angle with a short mouth and an angle with a short mouth. The result is that the angle with a large mouth opening is large, even if the side angle of the angle does not become large. Once again, the size of the angle is only related to the opening of the angle, not to the side length.

Step 4 summarize children's songs

Summarize today's learning content with a children's song sent by the village head, which conforms to the psychological age of the children in Grade Two, attracts students' attention and reminds them of the learning content of this lesson.