桌上放一枚硬币,硬币上放一个透明玻璃杯,空杯时可以从侧面看到杯底下的硬币,往杯里倒入适量的水后从侧面较大范围中看不到杯底下的硬币。对于这个现象的成因主要从光的全反射和光的强弱对人眼视觉的影响两方面来进行阐述,并从多个角度用实验进行检验和深入分析。 Put a coin on the table, place a transparent glass on the coin, view the coin under the cup from the side when empty cup, pour the right amount of water into the cup and can not see the coins under the cup from the larger side . The causes of this phenomenon are mainly explained from two aspects of the total reflection of light and the influence of the light intensity on the human visual system. Experiments are carried out to examine and analyze in depth from many angles.