KNOW: Why Clouds are White
The Clouds are white because the 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 colors, giving the impression that the sky is blue. But in a cloud, sunlight is scattered by much larger water droplets. These scatter all colors almost equally meaning that the sunlight continues to remain white and so making the clouds appear white against the background of the blue sky.
Detailed: How and why clouds are white
- Sunlight or 'visible light' can be thought of as a wave and a part of the electromagnetic spectrum. We can see the full spectrum when it is split up and spread out as a rainbow. The spectrum is shared with other types of waves, from really short x-rays and gamma rays to really long radio waves.
- Each visible color has a different wavelength; blue light has the shortest the wavelength at 400 nanometres and red light the longest at 700 nanometres. Smaller particles can scatter shorter wavelengths more efficiently, like those that are invisible to our eyes in the atmosphere, making the sky blue.
- Bigger particles like water droplets within a cloud scatter all wavelengths with roughly the same effectiveness. If we consider that there are millions of water droplets in a cloud, the scattered light interacts and combines to generate a white color.
- The clouds are white because the 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 colors, giving the impression that the sky is blue.
- But in a cloud, sunlight is scattered by much larger water droplets. These scatter all colors almost equally meaning that the sunlight continues to remain white and so making the clouds appear white against the background of the blue sky.
- Sunlight or 'visible light' can be thought of as a wave and a part of the electromagnetic spectrum. We can see the full spectrum when it is split up and spread out as a rainbow. The spectrum is shared with other types of waves, from really short x-rays and gamma rays to really long radio waves.
- Each visible color has a different wavelength; blue light has the shortest the wavelength at 400 nanometres and red light the longest at 700 nanometres. Smaller particles can scatter shorter wavelengths more efficiently, like those that are invisible to our eyes in the atmosphere, making the sky blue.
- Bigger particles like water droplets within a cloud scatter all wavelengths with roughly the same effectiveness. If we consider that there are millions of water droplets in a cloud, the scattered light interacts and combines to generate a white color.
