James Noonan, age 10, of Blue Point, Maine, for his question:

How long does a flash of lightning last?

Lightning is electricity discharged in the air. The air happens to be a turbulent cloud, heavy with moisture. This moist air resists the flash of electricity. It slows it up and forces it to take a curved, or branching path. For this reason the streak of lightning may seem to zig‑tag.

The discharge of electricity leaps from one point to another across several miles. It may be between two points in a cloud, between one cloud and another or between a cloud and the ground. Several flashes may follow along the same route in quick succession.

Would you guess the flash to last one second, half a minute, or only part of a second? A single flash of lightning is over in 0.0002 of one second. Several flashes along the same path may last as long as one second, 11 dazzling flash of lightning may seem to last longer than this, but it never does. Its light reaches us at the speed of about 185,000 miles a second. So we see the brilliant spectacle while it is happening.