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Let’s review our physics lessons

What does lightning look like?

A lightning flash is only centimetres thick, however, every metre shines as bright
as 1 million 100 watt light bulbs since the lightning flash is electrically charged.
It may come as a surprise that a lightning flash, with few exceptions, travels
from the ground to the clouds! Fractions of a second before the actual light-
ning flash there is a downward leader, however, this is hardly visible to the hu-
man eye.
What causes lightning?

Lightning originates from thunder cells which may have a diameter of several
kilometres. Positively and negatively charged areas are created due to an uneven
distribution of ice and water as well as updraft and downdraft winds in the cloud.
If the voltage differences become too high, an electrical discharge occurs (light-
ning flash). The thunder cells only last about 30 minutes and cause two to three
lightning flashes per minute during this time.

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