[教案设计说明]1.教学目标:(1)知道声音传播需要介质。(2)记住声音在空气中传播的快慢,知道液体和固体的传声比气体快。(3)知道耳的主要结构和作用。2.教学重点和难点。重点:(1)声音的传播需要介质。(2)耳的主要结构和作用。难点:声波的形成。 [Project lesson design description] 1. Teaching objectives: (1) Know that sound transmission requires media. (2) Remember how fast the sound travels in the air. Know that liquids and solids transmit sound faster than gas. (3) Know the main structure and function of the ear. 2. Teaching focus and difficulty. Focus: (1) The sound needs media. (2) The main structure and function of the ear. Difficulties: The formation of sound waves.