Mie scattering is a type of light scattering that occurs when light interacts with particles approximately equal to or larger than the wavelength of the light. This contrasts with Rayleigh scattering , in which the particles are much smaller than the wavelength of the light.
Mie scattering was first described by the German scientist Gustav Mie in 1908. It is especially important for light scattering by larger particles , such as dust, water droplets and fog , and is common in atmospheric phenomena.
1. Characteristics of Mie scattering
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Particle size : Mie scattering occurs when the size of the particles scattering the light is comparable to the wavelength of the light . This means that the light can be scattered in different directions.
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Colorless : Unlike Rayleigh scattering, which scatters blue light more strongly, Mie scattering has minimal effect on the color of the light. This allows the white color of the sky and other scattered colors in the atmosphere to be preserved, even in fog or smoke .
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Scattering for larger particles : This is especially important for larger particles, such as water droplets in clouds , smoke particles , or dust . This often leads to the perception of a white or gray sky instead of the blue sky we normally see.
2. How does Mie scattering work?
Mie scattering occurs when light particles (photons) collide with larger particles (such as water droplets or dust). The light is then scattered in a controlled manner in multiple directions , and the magnitude of the scattering depends on the ratio of the particle size to the wavelength of the light .
π Key feature : Mie scattering causes a mixing of colours , because the scattering can occur evenly over all colours of the visible spectrum, unlike the stronger scattering of blue light in Rayleigh scattering.
3. Difference between Rayleigh and Mie scattering
| Feature | Rayleigh scattering | Mie scattering |
|---|---|---|
| Particle size | The particles are much smaller than the wavelength of light. | The particles are equal to or larger than the wavelength of light. |
| Color change | Amplified blue light (shorter wavelength). | No colour preference ; even distribution. |
| Application | Mainly atmospheric air (blue sky). | Mainly fog, water droplets, smoke and larger particles. |
π **Rayleigh scattering is responsible for the blue sky, while Mie scattering often occurs in fog or cloudy conditions and can result in a white or gray sky .
4. Applications of Mie scattering
Mie scattering is important in various environments and applications:
| Application | Description |
|---|---|
| π« Fog and mist | Mie scattering causes a white fog by scattering of light by water droplets. |
| π§ Cloudy | Clouds scatter light through water droplets, creating a diffuse and gray light . |
| π¨ Air pollution | Smoke and dust particles in the air scatter light in a way that makes the sky gray or white . |
| π§ͺ Optical technology | Mie scattering is used to study particle size in various media (such as aerosols and liquids). |
π Mie scattering plays a crucial role in the scattering of light by larger particles in the atmosphere.
5. Formula for Mie scattering
The intensity of Mie scattering can be calculated using Mie theory, which focuses on the interaction between light waves and particles that are equal in size to or larger than the wavelength of light. The scattering intensity depends on the particle size and the wavelength of light .
π The intensity of Mie scattering decreases with particle size and is less dependent on the wavelength of light than Rayleigh scattering.
π‘ In short :
Mie scattering is a type of light scattering that occurs when light interacts with larger particles (such as water droplets, dust, or smoke ). It causes a uniform scattering of light , often resulting in a white or gray sky , as opposed to the blue sky we normally see due to Rayleigh scattering .