system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does the spark produced by tesla coil or any electrical discharge shaped like zig zag and not straight?
gpt
Air is normally an insulator, which doesn't allow electricity to flow through it. However, if there's a big enough voltage, it can rip electrons out of atoms in the air (called "ionization"). This creates a chain reaction: The free electron can knock out electrons from other atoms, ultimately creating a path of conductive plasma that the electricity can flow through. It's like an electric avalanche.

The reason it forms a jagged line is that it's a random process. It'll move into whatever direction the first ionized atom is, rather than moving in a straight line to the next best conductor it can hit.