材料准备:玻璃杯、白纸、笔(如图1)实验步骤:1.在白纸上写几个汉语拼音字母:mud,再画一个箭头(如图2)。2.把杯子装满水,然后把杯子靠近自己,那白纸放在前面(如图3)。3.把白纸在杯子边来回移动,当移动到适当的位 Material Preparation: glass, white paper, pen (Figure 1) Experimental steps: 1. Write a few Chinese pinyin letters on white: mud, and then draw an arrow (Figure 2). 2. Fill the cup with water and bring the cup closer to you, with the white paper on the front (Figure 3). 3. Move the white paper back and forth around the cup while moving to the proper position