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自然界中的声音,有的强,有的弱;有的高,有的低。为什么会有不同? 要帮助学生探究这些问题选用什么样的材料?教材中使用自行车,转动后轮让纸条在自行车的幅条中划过,随着转速的不同,能听到高低不同的声音,得出声音的高低是由物体振动的频率决定的。在教学实践中,我们发现这个材料有局限性。一是把纸条插到转动的自行车幅条中,容易擦伤手,有危险。二是自行车过于庞大,摆上讲台不方便。三是声音的强弱问题不能解决,需另觅材料。我们经过多次试验,发现扬声器这种材料很好。小扬声器是一种很常见的电子器件,它不只能发出某一种声音,而能发出高低强弱不同的声音,且操作控制灵活方便,这些特点对于学生探究声音的奥秘是很有利的。
The voice in nature, some strong, some weak; some high, some low. Why there are different? To help students explore these issues choose what kind of material? Teaching materials, the use of bicycles, rotating the rear wheel so that the paper strip in the bike across, with the different speed, can hear different levels of sound , Come to the sound level is determined by the frequency of vibration of the object. In teaching practice, we find this material has limitations. First, the note inserted into the rotating bike spokes, easy to scratch the hand, dangerous. Second, the bike is too large, put the podium inconvenient. Third, the strength of the sound can not be solved, need to find another material. After many tests, we found that the speaker is a good material. Small speakers are a very common type of electronic device. They can not only emit a certain sound, but also can produce different levels of sound, and the operation and control are flexible and convenient. These features are very beneficial for students to explore the mystery of sound.