一、雷电是我们司空见惯的自然现象,但它的成因却至今还是一个谜。自从富兰克林证实了闪电就是一种电火花后,关于闪电形成的机制就一直困扰着人们。科学家们发现,一般情况下,雷电云层要超过3公里厚度才可能产生雷电。这时,云层上部温度很低,带正电荷,云层底部则带负电荷。当正负电荷之间的电场足够强大时,就会击穿空气绝缘层,产生闪电。云层越厚,顶部温度越低,雷电越激烈。但是,为什么本来为中性的云层会分出正负电荷来呢?一种说法是雨滴或冰珠带着负电荷,而小尘粒和冰晶带正电荷。雨滴向下落而小尘粒和冰晶则在云层上部积聚。这样就产生了引 First, lightning is a common natural phenomenon, but its cause is still a mystery. Since Franklin has confirmed that lightning is a spark, the mechanics of lightning formation have been troubling people. Scientists have found that under normal circumstances, thunder and lightning clouds to more than 3 km thickness may produce lightning. At this time, the temperature in the upper part of the cloud is very low, with a positive charge, while the bottom of the cloud is negatively charged. When the electric field between the positive and negative charges is strong enough, it breaks down the air insulation and creates lightning. Thicker clouds, the lower the temperature at the top, the more intense lightning. However, why the neutral clouds divide the positive and negative charges? One way to say is that raindrops or ice beads carry a negative charge while small dust particles and ice crystals are positively charged. Drops of rain and small dust particles and ice crystals in the upper part of the accumulation of clouds. This led to the introduction