A giant spark
What Is Lightning?
Lightning is the same spark you get from a doorknob, scaled up billions of times.
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Step 1 of 5
Storm clouds are violently churning inside.
Air rushes up and down at enormous speed, carrying ice crystals and slushy hail with it. Everything is constantly colliding.
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Step 2 of 5
Collisions split the charge apart.
Light ice crystals pick up positive charge and rise. Heavier hail takes negative charge and sinks. The cloud ends up sorted top and bottom.
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Step 3 of 5
The charge difference gets enormous.
Negative at the cloud base pushes negative charge out of the ground below, leaving it positive. The pull between them builds to millions of volts.
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Step 4 of 5
Air normally blocks electricity — until it cannot.
Air is an insulator, which is why the charge builds instead of leaking away. Past a few million volts, the air itself tears open into a conducting path.
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Step 5 of 5
Then everything discharges in a flash.
A faint leader feels its way down, meets a streamer rising from the ground, and the main stroke blasts back up. It takes under a thousandth of a second.
Lightning heats the air to about 30,000°C — five times hotter than the surface of the Sun.
The short version
Lightning is a spark that jumps once a storm cloud has built up millions of volts against the ground.
Try it yourself
Shuffle across a carpet and reach for a metal door handle. That tiny snap is lightning at a scale you can survive.
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