Review the import first, interpret the target 1, and know the radius or diameter of the circle. How to calculate the circumference of a circle? Write the formula of the circle: c = or c = 2. Find the circumference of the following circle: (1) The radius is 1 m (2) The diameter is 3cm. 3. Perceive the cylinder as a whole: Please find the cylindrical object in your life. Second, think hard, finish 1 independently, and touch the cylinder on the surface (1). Touch the surface of the cylinder in your hand and tell me what you find. What parts does a cylinder consist of? (2) What are the names of the upper and lower surfaces you touch? What is the name of the surface around the cylinder you touch? What are their characteristics? 2, the height of the cylinder (1) self-study textbook P 1 1 example 1, take a cylinder object to point out its height, think about the characteristics of cylinder height? (2) Deepen perception: Which one is the easiest to measure in the face of these countless heights? (3) Try to complete P 1 1 "do". Tell me, what is a rectangle or square when it rotates? (4) What are the characteristics of cylinders? Third, cooperation and communication, dispel doubts and doubts 1, unfold one side of the cylinder (P 12 Example 2)( 1) Hands-on operation: Please take out the cylindrical objects with trademark paper in groups, cut the trademark paper separately, and then open it to observe the shape of the trademark paper. (2) Exchange discussion: How to cut the rectangle and square after unfolding? How to cut the unfolded parallelogram? (3) Find the length-width relationship between the unfolded rectangle and the cylinder. (1) Restore the unfolded rectangle to the side of the cylinder, unfold it again, and repeat the operation and observation. ② Tell your own findings: the length of this rectangle is _ _ _ _ _ at the bottom of the cylinder, and the width is _ _ _ _ _ of the cylinder. Check each other in pairs and say something wrong. (4) Extended discovery: the relationship between the base and height of the unfolded parallelogram and the side lengths of squares and cylinders. ① Discussion: Can a parallelogram be transformed into a rectangle in any way? ② Think about it: When the circumference of the bottom of the cylinder is equal to the height, what is the side development diagram? ③ Summary: No matter how the edges are cut, all kinds of figures can be converted into rectangles by cutting and mending, in which squares are special rectangles. Fourth, show and improve, test 1 in class, complete 1 and 2 questions in exercise 2 of P 15, and the team leader will check and ask questions. 2, level training: 1, consolidation training: complete P 15 exercise 2, questions 3 and 4. 2. Expansion and improvement: Complete "Do" on page 12. Organize the tutorial plan: 1. Draw a smiling face behind your completed learning goal against your learning goal. 2. Write down your gains from this lesson or remind yourself in red pen in the right column.