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where does thunder come from

Thunder comes from lightning: it’s the sound made when lightning suddenly heats and explodes the air around it, creating a shock wave that we hear as a rumble or crack of thunder.

Quick Scoop: Where does thunder come from?

The basic idea

When a lightning bolt flashes, it superheats the air in its path to tens of thousands of degrees in a tiny fraction of a second.

That air expands explosively, then quickly cools and contracts, and this violent in–out motion creates a powerful pressure wave—a sound wave—we call thunder.

Step‑by‑step: from flash to boom

  1. Lightning forms in a storm cloud because electrical charges build up and then suddenly discharge as a giant spark between cloud and ground or between clouds.
  1. That spark heats the air around the lightning channel to roughly 10,000–30,000°C, hotter than the surface of the Sun.
  1. The superheated air expands faster than sound can normally travel, creating a shock wave—like a tiny explosion stretched along the lightning’s path.
  1. As the air cools and contracts, the shock wave spreads outward and becomes the rolling sound of thunder that reaches your ears.

Why thunder sometimes cracks and sometimes rumbles

  • A sharp crack or loud boom usually means the lightning was very close, so you hear the shock wave from a short part of the lightning channel almost all at once.
  • A long, low rumble happens when the lightning is farther away or very long, so sound from different parts of the bolt arrives at your ears at slightly different times.
  • Obstacles like hills, buildings, and clouds can reflect and scatter the sound, stretching it out into that rolling, growling noise.

A simple way to picture it: lightning is like the flash of a camera, and thunder is the “bang” of a long, invisible firecracker drawn across the sky, where the burning fuse is the lightning channel heating and shaking the air.

Little extra: timing the storm

If you count the seconds between the flash of lightning and the sound of thunder, you can estimate how far away the strike was, because light arrives almost instantly but sound travels relatively slowly through air.

The bigger that gap in seconds, the farther away the lightning (and the storm) usually is, though you should still stay safe whenever you can hear thunder at all.

Information gathered from public forums or data available on the internet and portrayed here.