Video
Lightning
Lightning can flash within clouds, but it is cloud-to-ground lightning that does the most damage. This type of lightning starts off as a negative electrical charge in the clouds.
The charge zigzags downward until it meets a positive charge produced on Earth’s surface. This connection creates a flash of lightning. The lightning bolt’s negatively charged downstroke is invisible, because it moves at 60,000 miles per second. But the positively charged upstroke moves more slowly, and that is the flash we see. Lightning hits Earth about 100 times every second.
