Recently, a famous film star Zhao Wei released an appeal to put less fireworks, fog and haze governance microblogging attracted everyone's attention. Microblogging in a "small start from the side, put an end to the Tyndall phenomenon" and bring you a new term, "Tyndall phenomenon." What is the Tyndall phenomenon? It haze and fog What is the relationship? Tyndall phenomenon can be put an end to it?
Tyndall phenomenon, by the British scientist John? Tyndall research in the mid-19th century and its name. Briefly, Tyndall phenomenon when a beam of light is dispersed by the dispersion of certain size particles (including liquid and gas), can produce a visible optical phenomenon.
So, this is how the optical path to generate it? This is the scattering of light by the particulate matter present in the dispersion caused. If the size of the dispersion particles and the wavelength of incident light can be fairly (ie generally greater than 1/10 of the wavelength of incident light, visible light is about the size of more than tens of nanometers can be), when the light shines on such particles , there will be a random part of the light in other directions diverge, which resulted in the scattering of light. These are no longer spread along the irradiation direction of the light seen by us, which form a clear optical path.
However, if the particles are too large or too small, the impact will occur scattering. If the particles are too small, this simple change in the optical path of the scattering (called Mie scattering) becomes weak, so that Tyndall phenomenon was no longer significant. When the particle diameter of the molecular scale, and the other depends on the wavelength of the incident light scattering mode (called Rayleigh scattering) become the dominant factor, but due to the coherent Rayleigh scattering of light between the individual small particles, and therefore can not form visible way. Tyndall phenomenon use this feature, you can distinguish the dispersed material as a separate molecule present in the solution, as well as molecules (size between 1-100 nanometers) the presence of colloidal basis. In the other hand, if the particles are too large, the particles of the reflected light becomes a dominant factor, the same is not conducive to the Tyndall phenomenon.
Then we should know the relationship between the haze and the Tyndall phenomenon: In the fog and haze, a large number of different sizes of small particles suspended in the air, these particles smaller portion sized to meet the Tyndall phenomenon conditions, if the open street lights in fog or haze, you can see a typical phenomenon Tyndall light path. So, to say, haze can indeed produce Tyndall phenomenon.
Tyndall phenomenon can be "eliminate" Why? Actually, this is not appropriate. Tyndall phenomenon is the optical properties of the dispersion, as long as the dispersion of particles in the size you will be able to produce Tyndall phenomenon. Moreover, Tyndall phenomenon only required particle size, and composition of the particles did not ask, haze formation Tyndall phenomenon, but nothing consistent with the size of suspended particles. In fact, in a clean environment, if there is mist drifting away, the same phenomenon can be observed Tyndall. However, to be noted that, in thick fog, due to the large particle droplets, when the light is diffuse reflection light droplets generated between the road and contribute more. After all, we can see that the fog is the result of the reflection of light.
In summary, the Tyndall phenomenon itself is unable to stop, but we can reduce emissions, less put fireworks and other ways to reduce the haze particles. From this perspective, through our efforts, can indeed prevent the formation of haze due to the Tyndall phenomenon.
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