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九年义务教育初中物理第一册新教材的绝大部分实验接近生活,简单易懂,直观性强,说理清晰,论证有力,但也还有些实验的实验方法还不尽完美。本文对声学部分几个演示实验提出以下改进意见。 1.“声音的发生和传播”一节中有一个演示“一切正在发声的物体都在振动”的实验(图1)。音叉的选择应是振动频率高,叉间间距大的音叉,课本上用“泡沫塑料球”,经我反复实验,发现以“小钢球”或“乒乓球”效果为最好。 2.在演示“声音是靠空气传播”实验时,教材中的方法如图2所示,实验效果不明显。其原因是两音叉的固有频率必须完全相同,而且实验要求音叉振动能量越高,效果越明显,实
The vast majority of the new textbooks for the first year of the junior middle school physics of the nine-year compulsory education are close to life, easy to understand, intuitive, clear and powerful, but some experimental methods are still not perfect. This article proposes the following improvements to several demonstration experiments in the acoustics section. 1. In the section “The Occurrence and Propagation of Sound”, there is an experiment demonstrating that “every sounding object is vibrating” (Figure 1). The choice of the tuning fork should be a tuning fork with a high frequency of vibration and large fork spacing. The textbook uses “foam ball”. After repeated experiments, I found that the effect of “small steel ball” or “ping-pong” is best. 2. In the demonstration of “The sound is transmitted by air” experiment, the method in the textbook is shown in Fig. 2. The experimental result is not obvious. The reason is that the natural frequency of the two tuning forks must be exactly the same, and the higher the tuning fork vibration energy, the more obvious the effect is.