KidZone Science
Deeper Dive into Atmospheric Scattering

What Is Atmospheric Scattering?

• Atmospheric scattering occurs when light from the sun interacts with particles and gases in the Earth's atmosphere. This interaction causes light to spread out in different directions. The way light scatters depends on the size of the atmospheric particles compared to the wavelength of the incoming light.

Rayleigh Scattering: The Blue Sky

• Rayleigh scattering is named after the scientist Lord Rayleigh, who explained why the sky is blue. This type of scattering affects smaller particles in the atmosphere, like molecules of oxygen and nitrogen, which are much smaller than the wavelength of visible light.
• In Rayleigh scattering, shorter wavelengths of light (blue and violet) are scattered more efficiently than longer wavelengths (red and orange). Since our eyes are more sensitive to blue light and some violet light gets absorbed by the upper atmosphere, the sky appears blue to us during the day.

Mie Scattering: Why Clouds Are White

• Mie scattering occurs with particles that are about the same size as the wavelength of visible light, such as water droplets in clouds or pollution particles. Unlike Rayleigh scattering, Mie scattering doesn't favor any particular wavelength, so all colors scatter similarly.
• Because all colors of light are scattered equally, clouds appear white, which is the result of mixing all the colors of light together. When clouds are very thick or dense, less light makes it through, making them look gray.

The Impact of Particles on Scattering

• The amount and type of particles in the atmosphere can greatly affect how light is scattered. For example, after a volcanic eruption, tiny ash particles can scatter sunlight and create vivid sunsets. Pollution can also change the way light is scattered, sometimes leading to hazier skies.

Experiment: Simulating Scattering

• Students can simulate Rayleigh and Mie scattering using a simple experiment. Fill one clear container with water (to represent a clean atmosphere) and another with water mixed with a small amount of milk (to represent an atmosphere with larger particles). Shine a flashlight through each container in a dark room and observe the difference in light scattering.

This section helps students understand the complexities of atmospheric scattering and its effects on the sky's appearance. Through explanations and hands-on experiments, students can grasp how the size of particles influences the scattering of light and contributes to the natural beauty of our skies.