What is a beam of light called from the clouds?

What is a beam of light shining through the clouds called?

The beam of light passing through the clouds is called the Tyndall effect. It means that when a beam of light passes through a colloid, it can be observed from the direction of vertical incident light. A bright "pathway" appears in the colloid, usually in the early morning, at sunset, or after rain when there are more clouds.

Tyndall effect (Tyndall effect), also called "Tyndall phenomenon", or "Tyndall phenomenon", "Tynzel effect", Tyndall effect, is a light scattering phenomenon .

When a beam of light passes through the colloid, a bright "pathway" can be observed in the colloid from the direction of vertical incident light. The emergence of the Tyndall effect also means that light can be seen.

The photography industry also calls it "Jesus light". It usually appears in the early morning, at sunset or after rain when there are more clouds and there is fog or dust in the atmosphere. The sun just shines on it and is divided into strips, sometimes into a large piece, which looks particularly spectacular.

Cause

During the propagation of light, when light strikes particles, if the particles are many times larger than the wavelength of the incident light, reflection of light will occur; if the particles are smaller than the wavelength of the incident light , light scattering occurs. At this time, what is observed is the light waves surrounding the particles and radiating around them, which is called scattered light or opalescence. The Tyndall effect is the scattering phenomenon of light or opalescence.

Since the diameter of true solution particles generally does not exceed 1nm, colloidal particles are between solute particles and turbid liquid particles in the solution, with diameters ranging from 1 to 100nm. It is smaller than the wavelength of visible light (400nm~700nm). Therefore, when visible light passes through the colloid, significant scattering will occur.

For a true solution, although the molecules or ions are smaller, the intensity of the scattered light is significantly weakened as the volume of the scattering particles decreases. Therefore, the scattering effect of the true solution on light is very weak. In addition, the intensity of scattered light also increases as the particle concentration in the dispersion system increases.

So, colloids can have Tyndall phenomenon, but solutions almost don’t. Tyndall phenomenon can be used to distinguish colloids and solutions. Note: When light passes through the suspension, light paths sometimes occur, but Because the particles in the suspension obstruct the light too much, the resulting light path is very short.