Thunder storm over Wigton

There was a loud thunder storm over Wigton last night. We don't get many storms this far north. I filmed it but found that I didn't get any nice forks of lightning, just the lit up sky shown. The classic thing to do is to count. Light does have a finite speed - 300,000,000 metres per second. That's so fast that we can assume that we see the lightning as soon as it is produced. This is not true of more distant objects like the Sun. The light from the Sun takes 8 minutes to arrive. Thunder is made by the lightning heating the air so rapidly that there is a sonic shock wave as the air expands violently. The speed of sound in air is around 330 metres per second, though it depends slightly on temperature. That means it goes about 1km in 3 seconds, so 1 mile is roughly 5 seconds. I count slowly. I counted to 10 for this flash. The nearest was 5 seconds and later I got to 20 seconds!