波动图象是本章的重点和难点 .本文就如何确定波动图象中质点的振动方向谈点教学体会 .1　上下坡法波的传播速度方向 ,介质中质点的振动方向 ,某时刻的波形图三者之间存在一定的关系 .在已知波的传播方向 ,某时刻的波形图的情况下 ,根据“上下坡法”可以求出介质中质点振动的方 The fluctuating image is the focus and difficulty of this chapter. This article discusses how to determine the vibration direction of the particle in the oscillating image.1 The direction of the propagation speed of the uphill and downhill waves, the direction of the vibration of the particles in the medium, and the waveform at a certain moment. There is a certain relationship between the two. In the case of the known wave propagation direction, the waveform of a certain time, according to the “up and down slope method” can be found in the media vibration of the particle side