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| Special Properties of Colloids |
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| When a colloidal solution is viewed through a powerful microscope, the colloidal particles can be seen moving in a random zig-zag path. This zig-zag motion of colloidal particles is called Brownian movement. This random motion is due to collisions between the colloidal particles. |
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| Brownian movement of colloidal particles |
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| For example, when a beam of light passes through a dark room, the dust particles can be seen moving in rapid, random fashion. |
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| When a powerful beam of light is passed through a colloidal solution placed in a dark room, the path of the beam gets illuminated and appears as a glow in the colloidal solution. This is because of scattering of light by the colloidal particles. |
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| Shaft of light are visible coming through trees in a forest. |
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| For example, this effect can be noticed in a 'Sun-beam' that filters through the (glass) sky light of a tiled roof. |
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| The migration of colloidal particles towards only one of the charged electrodes, under the influence of electric field is termed electrophoresis. |
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