Why are dark clouds black?

It is precisely because of the accumulation of fog drops and the transmission of light that the white clouds slowly turn black or grayish black.

There are many kinds of dark clouds, such as layered clouds, isolated cumulus clouds and wave clouds. Thick layered clouds, or cumulonimbus clouds, the light from the sun and the moon is difficult to transmit, and the clouds look black; Slightly thinner layered clouds and wave clouds look gray, especially in wave clouds, and the edges of the clouds are even grayer.

In summer, surface water evaporates rapidly under the scorching sun, making the air humidity higher and higher; The temperature at high altitude is lower than the surface temperature, so the water vapor first reaches saturation and supersaturation at high altitude; There will always be some dust in the sky, which will become the condensation center, so that saturated steam and supersaturated steam will condense into fine water droplets; When the fog drops are dense enough, they become white clouds visible to the naked eye; As the fog drops get bigger and bigger, the white clouds turn into dark clouds.