Home Curiosities What is the Tyndall effect?

What is the Tyndall effect?

We are surrounded by different physical phenomena that we are not aware of, or better say, we don’t question.

Surely more than once you have been in a room and you have noticed that the ray of light coming through the window lets you see the particles that are suspended in the air.

As we mentioned, you may not have been aware, but what you are witnessing is the Tyndall effect. If you’re still wondering what the Tyndall effect is, keep reading and you’ll find out.

The Tyndall effect, named after the Irish physicist John Tyndall, who studied the effect in 1869, is a physical phenomenon that allows the particles of a colloidal mixture or a gas to be distinguished because they disperse light.

Thanks to this phenomenon we can identify between homogeneous mixtures or true solutions and colloidal mixtures.

The true solutions or homogeneous mixtures are those mixtures in which the components cannot be identified from each other.

They are formed by a solvent, the component in greater proportion and that is usually water and the solute, the component in the smaller proportion which dissolves.

In this case, the particles of the solute are so small that they cannot be filtered or detected under a microscope, much less with the naked eye.

The Tyndall effect is observed on a daily basis

On the other hand, the heterogeneous mixtures also called “suspensions” are mixtures of solvents with large particles that can sometimes be observed with the naked eye.

There are other types of mixtures, in which particles of intermediate size participate and which are called colloidal mixtures. In this case, the particles, although not visible to the naked eye, they are capable of dispersing light.

You can also observe the Tyndall effect in the sunbeam passing between trees in the forest. Image source: Pixabay

In true solutions or in gases without particles in suspension, the light does not scatter and these are transparent.

On the other hand, in colloidal mixtures, although not visible to the naked eye, they are able to disperse or absorb light, making them distinguishable when an intense beam of light passes through them.

Some everyday examples in which we clearly observe the result of the Tyndall effect is:

  • As we have said before, the room in which there is dust suspended in the air and a ray of sunlight passes through the window and makes these particles visible.
  • Another example is the headlights of the car crossing the fog, or in the rays that pass through the trees.

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