What is the Tyndall effect?

What is the Tyndall effect?

• A. The scattering of light by colloid particles.
• B. The complete dissolution of solute in solvent.
• C. The absorption of light by a solvent.
• D. The reflection of light by a smooth surface.

Answer: (A)

The Tyndall effect is the scattering of light by particles dispersed in a colloid. In a colloidal mixture, the particles are large enough to redirect some of the light as it passes through, making the beam visible in the medium (think of a flashlight beam through milk, fog, or smoke). In a true solution, the dissolved molecules are too small to scatter visible light, so the beam isn’t seen. This distinguishes colloids from solutions. It’s not about how light is absorbed, reflected by a smooth surface, or simply dissolved; it’s specifically the outward scattering by the suspended particles that creates the visible beam.

The Tyndall effect is the scattering of light by particles dispersed in a colloid. In a colloidal mixture, the particles are large enough to redirect some of the light as it passes through, making the beam visible in the medium (think of a flashlight beam through milk, fog, or smoke). In a true solution, the dissolved molecules are too small to scatter visible light, so the beam isn’t seen. This distinguishes colloids from solutions. It’s not about how light is absorbed, reflected by a smooth surface, or simply dissolved; it’s specifically the outward scattering by the suspended particles that creates the visible beam.