Question

why clouds have a colour white

Answer 1

Clouds are white because light from the sun is white. As light passes through a cloud, it interacts with the water droplets, which are much bigger than the atmospheric particles that exist in the sky.

When sunlight reaches an atmospheric particle in the sky, blue light is scattered away more strongly than other colours, giving the impression that the sky is blue.

But in a cloud, sunlight is scattered by much larger water droplets. These scatter all colours almost equally meaning that the sunlight continues to remain white and so making the clouds appear white against the background of the blue sky.

Answer 2

Clouds are made of tiny round water droplets