By Jovi Esteve ((Meteorologist for Ràdio 9. RTVV)
In this article we will clarify a concept that many people are mistaken about. You will have heard at some point that clouds are made up of water vapour. Far from it! Water vapour, which is water in its gassy form, is an invisible gas that we cannot see. Therefore, if clouds were only made up of water vapour, we would not be able to see them – they would be invisible and, truth be said, we would be missing out on one of those wonderful gifts that nature gives us freely. So, we may ask ourselves:
What are clouds made of?
Clouds are quite simply made up of small water droplets, much smaller than raindrops, but still water in its liquid form (or solid, depending on the height). When sunlight reaches the clouds, the tiny water droplets that make them up disperse and reflect all the visible colours that make up light. By dispersing and reflecting all colours equally at the same time, what we see is the mix of them all, that is, the colour white. That is why clouds appear white to us. When clouds are very dense and large, sunlight cannot go all the way through them, and so they take on those darker and greyer tones. On the other hand, the sun’s rays at dawn or sunset (in the evening) can sometimes adorn them with those characteristic sunset colours.