# Which is thunder or lightning

## How far is the thunderstorm?

Anyone who is afraid of thunderstorms and cannot fall asleep with lightning and thunder should have mastered this simple arithmetic trick with which one can estimate how far the thunderstorm is away and whether it is approaching or moving away.

When there is a thunderstorm, you always see the lightning first - and then the thunder follows at a distance. This is because light travels faster than noise, i.e. as sound. The light has a speed of 299,792,458 meters per second - or just under 300,000 kilometers per second. The sound has a speed of 340 meters per second. When you see lightning, you have to count the seconds until you hear the thunder. You then take 340. That way you can estimate the distance of the thunderstorm pretty precisely.

An example: "Blitz", twenty-one. Twenty-two. Twentythree. Twenty four. Twenty-five. "Thunder". So it took five seconds for the sound to reach us. 340 meters times 5 is 1700 meters. So the thunderstorm is 1.7 kilometers away from you.

The fact that you can say this so precisely is because lightning and thunder, where they arise, always occur at the same time. However, since the sound takes much longer to reach our ears than the lightning to our eyes, we usually see the lightning first and then hear the thunder. And so you can actually estimate the distance well.

### And then?

If you want to know now whether the thunderstorm is moving away or approaching, you wait for the second lightning and thunder. Then you calculate the distance again using the formula. If the second measurement results in a shorter distance than the first, the thunderstorm is approaching, if the second measurement results in a longer distance, the thunderstorm is moving away. And when you've calculated all of this, the thunderstorm must have moved on by now, and you can fall asleep with peace of mind.