What is a Tyndall effect

  Tyndall effect is a phenomenon which involves the scattering of light rays by particles in a colloid or a very fine suspension when the beam of light passes through them.

When beams of lights are directed at a colloid or a very fine suspension, the individual particles of the colloid or suspension will not permit the light rays to freely pass through. Instead, the rays and the particles will undergo collision, resulting in the rays  being scattered and reflected by the particles. Making the path of the light visible.

In a solution, light travels in a straight line but when it passes through a colloid or a fine suspension, it will deviate as a result of getting reflected and dispersed by the colloidal particles, making the rays to appear visible. This phenomenon is called tyndall effects. It was named after an Irish physicist John Tyndall following this discovery.

The intensity of the scattered light depends on the frequency of the light and the size of the particles. It even stated that:  "the intensity of the scatterd light is inversely proportional to the fourth power of it wavelength". Thus, it is observed that blue lights (with a shorter wavelength) is scarttered strongly than red lights (with a longer wavelength).

You might be wondering;  'why is this reaction unique anyway'? Tyndall effects is quite responsible for so many color effects in most substances both organic and inorganic. A more common example of tyndall effect is evidence by the blue color of the eye. This is caused by light getting scattered by the translucent layer of the iris.

Other examples of tyndall effects includes:

• Scattering of light by particles of milk: Milk is an example of an emulsion (a type of colloid), containing rounded particles of fats and protein. When a flashlight is directed at a glass of milk, the light rays will scatter and the path will be visible in the glass.

• The blue colors presents in smokes from a motorcycle or a car is an example of tyndall effects, where light is scattered by smoke particles.

• Scattering of lights by water droplets in fogs: When a flashlight or a headlight is directed at foggy environments, the path of the light rays from the headlight will become visible as shown in the image below.

• When sunlight finds it way in a room where lots of dust particles are suspended, the dust particles will scatter the light from the sun, forming a visible path.

• In the laboratory, tyndall effects is used to distinguish between a true solution and a colloid solution. This is because the components forming a true solution are very tiny and unable to reflect any light rays that passes through them. While in a colloid, the particles are large enough to reflects light rays, exhibiting tyndall effect.

Another phenomenon which involves the scattering of light is the rayleigh effect.