When it starts to rain, one of the signs to recognize is the dark gray color of the clouds. Why do the clouds change color like that?
The thickness or height of the cloud is the reason why clouds appear gray. When clouds are thin, they allow most of the light to pass through and appear white. However, like other light-transmitting objects, clouds follow the rule that the thicker they are, the less light can pass through.
Sky scenery when rain is approaching. (Photo: internet).
First, we need to understand the nature of clouds. Clouds are a collection of many tiny water droplets or ice crystals, formed when water vapor condenses in rising air pockets. Under normal weather conditions, the air continues to rise, causing the cloud to accumulate more mass.
These tiny water droplets and ice crystals are small enough to scatter all colors of light. When light is composed of all colors, our eyes perceive it as white.
When clouds are thin, they allow most light to pass through, appearing white. As the thickness of the cloud increases, the bottom of the cloud becomes darker due to less light passing through, yet it can still scatter all colors. To the naked eye, we will see the cloud as gray, and if we pay attention, we will notice that the flat bottom of the cloud is always darker compared to the sides.