Thunder and lightning: how a thunderstorm forms

In short: Lightning is an enormous electrical discharge between cloud and ground or between clouds. Thunder is the bang of the air heated explosively in the process.

In more detail: In thunderclouds ice crystals and graupel rub against each other and separate electric charges. When the voltage becomes too high, lightning strikes through the air.

In detail

• Temperature: A lightning channel reaches about 30,000 °C, several times hotter than the Sun’s surface.
• Light and sound: Light is there almost instantly; thunder needs about three seconds per kilometre (echo-und-schallgeschwindigkeit).
• Behaviour in a storm: Seek buildings or cars, avoid trees and open areas, stay out of the water.
• Lightning rod: It leads the current in a controlled way into the ground.
• Faraday cage: A metal car protects the occupants because the current flows on the outside.