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初中应用物理知识竞赛关于声现象的主要知识点有:一、声音的产生声音是由物体的振动而产生的.发声的物体称为声源,固体、液体、气体都可以发声,都能成为声源.例1有四个实验现象:A.将正在发声的音叉接触水面,水面溅起水花;B.吹响笛子,手指按住不同的孔,发出不同的声音:C.吊着的大钟上固定一支细小的笔,钟敲响后,将纸在笔尖下迅速水平拖过,纸上出现弯曲的图线;D.锣发声的时候,用手按住锣面,锣声消失.能够说明声音的产生条件的实验是(填入序号).解析:实验中的水、笔、纸是为了显示物体的振动,而“用手按住锣面”是为了阻碍物体的振动,这都是为了探究声音的产生条件;吹响笛子,手指按住不同的孔,发出不同的声音,这是为了改变发声体的长
The main points of knowledge about acoustic phenomena in junior high school Applied Physics Quiz are: First, the sound is generated The sound is generated by the vibration of the object, the sound object is called the sound source, solid, liquid, gas can sound, can become sound Source. Example 1 has four experimental phenomena: A. The sounding fork touch the water surface, water splashing; B. Sounded the flute, fingers hold different holes, make a different sound: C. hanging bell Fixed a small pen, the bell rings, the paper quickly tipped over the tip of the pen tip, the paper appears curved map; D gong sound, hand gongs gongs, gongs disappear. Interpretation of the conditions of the sound generated experiment (fill in the serial number.) Analysis: Experiment water, pen, paper is to show the vibration of objects, and “hand-hold gongs” is to hinder the vibration of objects, which Is to explore the conditions of the sound; sounded the flute, fingers hold different holes, make a different sound, which is to change the length of the sound body