What is the Tyndall Effect?

 

What is the Tyndall Effect?

The Tyndall effect is a phenomenon whereby the light beams that are aimed at a colloid are scattered. All colloidal fluids and certain extremely fine suspensions exhibit this effect. Consequently, it can be used to confirm whether a certain solution is a colloid. Both the frequency of the incident light and the density of the colloidal particles affect how much light is dispersed.

The presence of colloidal particles in the solution prevents a light beam from passing through a colloid fully. Colliding with the colloidal particles, the light is dispersed (it deviates from its normal trajectory, which is a straight line). The light beam's course can be seen thanks to this scattering, as seen in the illustration below.

When compared to red light, blue light is generally spread more. This is because blue light has a shorter wavelength than red light. This explains why motorbike smoke occasionally has a blue tint to it.

Irish physicist John Tyndall made the initial discovery of the Tyndall effect, for which he also received the name. The particles that produce the Tyndall effect can have dimensions between 40 and 900 nanometers (1 nanometer = 10-9 metre). In contrast, the visible light spectrum has a wavelength range of 400–750 nanometers.

Examples of the Tyndall Effect

Milk is a colloid made up of fat and protein globules. A ray of light is dispersed when it strikes a glass of milk. The Tyndall effect is well illustrated in this situation.

The path of the light becomes evident when a torch is turned on in a foggy atmosphere. In this instance, the fog's water droplets are what cause the light scattering.

Viewed from the side, opalescent glass has a bluish hue. However, when light is shone through the glass, orange-colored light manifests itself.

How Does the Tyndall Effect Affect Blue Eye Color?

The quantity of melanin in one of the layers of the iris is the main distinction between blue, brown, and black coloured irises. When compared to a black iris, the layer in a blue iris contains significantly less melanin, which makes it translucent. The Tyndall effect causes light to be scattered as it strikes this translucent layer.

Caused by the Tyndall Effect, blue iris

Blue light is more widely diffused than red light because it has a shorter wavelength. The light that is not scattered is absorbed by a deeper layer in the iris. These irises acquire their distinctive blue colour because the bulk of the dispersed light is blue.

The scattering of light is involved in numerous phenomena. Examples of similar phenomena include Mie scattering and Rayleigh scattering. The reason the sky is blue in a clear day is because air molecules scatter light, which is a type of Rayleigh scattering. To illustrate Mie scattering, when the sky is clouded, the relatively large cloud droplets are what cause light to scatter.