1, class, what season is it? (Autumn) Yes, it's autumn now. It's cold and leaves are falling gently from the trees. (Post a leaf model) You see, the teacher also brought you a big leaf today. Do you like it? A little ant also likes this leaf very much. Look, it uses this leaf as a playground. Please watch carefully and see how this little ant moves on the edge of this leaf. What did you find through observation? (Little ants crawling around the leaves), what can a circle say? (a week). Today, in this class, we will study this problem for about a week. (blackboard writing: one week)

Second, practice and feel the circumference.

1, touch it

(1) Please take out the leaves collected before class, choose one you like best, and touch its face first. How do you feel? (Slippery) Then can you touch its sideline like a small ant climbing a leaf?

(2) Students touch the leaves.

(3) Who wants to come to the front and talk about how you touched the edge of the leaves for a week?

(4) Students perform, (say and touch).

Step 2 draw a picture

(1) Just now, you touched the leaves for a week. Can you find the week of leaves? Please take out your colored pencils and draw a picture!

(2) Students draw leaves. After painting, do the deskmates look at each other beautifully?

(3) Who wants to come to the front and describe the week of this big leaf? Ask a student to draw a leaf model in front of him. Can you tell us how you drew it? Ask the students to point out and say where they started and where they ended. ) Take down the leaf model. Do you think it looks good?

(4) Do you draw like him? Please raise your hand if there are different ways? Ask a classmate to describe it. )

Summary: As you can see, no matter how you draw, you always draw along the edge of the leaf, right?

Step 3 look for it

(1) In life, the surface of many objects is like a leaf for a week. Can you find the faces of these objects around us?

Look, touch and say between your deskmates.

(2) Group report. What kind of face do you want? Where is the week when you touch it? )

Step 4 draw a picture

(1) The students are really looking for a lot. To encourage you, the teacher also prepared some graphic gifts for you. Do you want it? But the teacher has one condition. Only by drawing its week correctly can you get these gifts. Please open the envelope on the desk, choose a figure you like, and draw the edge of this figure with colored pencils. Start painting!