So why are clouds sometimes grey?Ĭloud bases are often grey as a result of the same scattering that makes them white. If we consider that there are millions of water droplets in a cloud, the scattered light interacts and combines to generate a white colour. Smaller particles can scatter shorter wavelengths more efficiently, like those that are invisible to our eyes in the atmosphere, making the sky blue.īigger particles like water droplets within a cloud scatter all wavelengths with roughly the same effectiveness. The spectrum is shared with other types of wave, from really short x-rays and gamma rays to really long radio waves.Įach visible colour has a different wavelength blue light has the shortest wavelength at 400 nanometres and red light the longest at 700 nanometres.
Larger than light full#
We can see the full spectrum when it is split up and spread out as a rainbow. Sunlight or 'visible light' can be thought of as a wave and a part of the electromagnetic spectrum. 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. 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.īut in a cloud, sunlight is scattered by much larger water droplets. 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. Clouds are white because light from the Sun is white.
0 kommentar(er)
