An example of the Tyndall Effect is how the headlights of a car are not able to shine all the way through fog. Headlights cannot penetrate fog because it is a colloidal substance, meaning that fog is made up of scattered particles. When light hits a substance with scattered particles, it collides with the particles, causing the light to scatter in multiple directions.
Another example of the Tyndall Effect is the way certain eyes appear to be blue. This is because the turbid layer of blue eyes contains less melanin, a substance that absorbs light. With less melanin, wavelengths of light can pass through the turbid layer. The shortest lightwave reflects a blue color, so this is the color the eye appears to be.
This same effect occurs when flour is mixed with water in a glass. When a light is shined on the glass, the mixture appears to be blue. This is because only the shortest lightwave, which is blue, is able to pass through the dense mixture. Ultimately, the Tyndall Effect is a way of determining whether a substance is a true solution or a colloidal. In general, colloidal substances contain larger particles, which scatter light and prevent longer lightwaves from passing through the substance.