Particulas líquidas y solidas flotando en la atmósfera

I was reading an interesting article about clouds. It was discussing their role in cooling the earth because they reflect heat from the Sun. As the earths atmosphere continues to rise due to man made factors it’s causing there to be less clouds amplifying the effects of global warming.

They ‘float’ in the sky because they are less dense than the air underneath them. When they become more dense they fall to earth as precipitation.

I’m going to hazard a guess that the reason you see them is due the water molecules refracting the light.