Weather
On a day when the sky is overcast, the sunlight passes through the turbid layer of the clouds, resulting in scattered, diffuse light on the ground. This does not exhibit Tyndall scattering because the cloud droplets are larger than the wavelength of light and scatter all colors approximately equally. On a day when the sky is cloud-free, the sky's color is blue in consequence of light scattering, but this is not termed Tyndall scattering because the scattering particles are the molecules of the air, which are much smaller than the wavelength of the light. When sunlight has a greater distance to travel through the atmosphere (at sunrise and sunset) this effect is greater. The Rayleigh Effect is in combination with the Tyndall effect as microscopic dust particles at lower levels scatter shorter wavelength (blue) light away and allow longer (red) wavelengths to reach the observer. Thus the degree of red in a sunset varies depending on the weather. On occasion, the term Tyndall effect is incorrectly applied to light scattering by macroscopic dust particles in the air. However, this is more like reflection, not scattering, as the macroscopic particles become clearly visible in the process.
Read more about this topic: Tyndall Effect
Famous quotes containing the word weather:
“This is the weather the cuckoo likes,
And so do I;
When showers betumble the chestnut spikes,
And nestlings fly:”
—Thomas Hardy (1840–1928)
“Every incident connected with the breaking up of the rivers and ponds and the settling of the weather is particularly interesting to us who live in a climate of so great extremes. When the warmer days come, they who dwell near the river hear the ice crack at night with a startling whoop as loud as artillery, as if its icy fetters were rent from end to end, and within a few days see it rapidly going out. So the alligator comes out of the mud with quakings of the earth.”
—Henry David Thoreau (1817–1862)