Einstein as a speed devil

How fast should you drive towards a red traffic light to see it appear as green?

Thunder and lightning

Why does a flash of lightning take only an instant, while the corresponding thunder can last for a few seconds? You might have expected that that the sound is caused by the flash, and that the thunder should therefore be audible also for an instant.

Rocket launch

Why are the European Ariane rockets launched from the Korou site in French-Guyana, South-America, and not simply from some place in Europe where the rockets are partly built?