What Causes Thunder and Lightning?

课文

1. Lightning is a giant spark of electricity that jumps between clouds, within a cloud, or from a cloud to the ground.

   闪电是云间、云内或云与地面之间产生的巨大电火花。

2. It forms when rising and falling air currents cause ice particles and water droplets to collide inside storm clouds.

   它形成于上升和下降的气流使雷暴云内的冰粒与水滴发生碰撞时。

3. These collisions separate positive and negative charges, building up huge voltage differences across regions of the cloud.

   这些碰撞使正负电荷分离，在云内不同区域间形成巨大的电压差。

4. When the electric field becomes strong enough, the air—normally an insulator—breaks down and conducts electricity suddenly.

   当电场强到一定程度，原本是绝缘体的空气便被击穿，突然导电。

5. That rapid flow of electrons heats the air to around 30,000°C, which is five times hotter than the Sun’s surface.

   电子的快速流动将空气加热至约30,000°C，是太阳表面温度的五倍。

6. The superheated air expands explosively, creating a shock wave we hear as thunder.

   过热空气剧烈膨胀，产生我们听到的雷声冲击波。

7. Because light travels faster than sound, we always see lightning before hearing thunder.

   因为光速远快于声速，我们总是先看到闪电后听到雷声。

8. You can estimate how far away lightning struck by counting seconds between flash and boom—every three seconds equals about one kilometer.

   可通过闪电与雷声之间的秒数估算距离：每3秒约对应1公里。

9. Lightning rods don’t attract lightning but safely direct its current into the ground if a strike occurs nearby.

   避雷针不会主动吸引闪电，而是在附近发生雷击时将电流安全导入地下。

10. About 100 lightning bolts hit Earth every second, yet fewer than 10% of them strike the ground directly.

    地球每秒约遭受100次闪电，但其中直接击中地面的不足10%。