Colloid facts for kids
A colloid may be a mixture of one substance that may spread out evenly inside another substance. They may be in two different phases or states of matter.
One substance can be the dispersion medium, such as water or gas. The other is kind of dispersed medium, sometimes called the 'internal phase'. This is never tiny solid particles. Otherwise, if the dispersion medium is a gas, then the internal phase may be either tiny particles or tiny droplets of a liquid.
Definition: A colloid is a substance microscopically dispersed evenly throughout another substance. The dispersed-phase particles have a diameter between about 5 and 200 nanometers. Colloids can be classified as follows:
| Medium/phase | Dispersed phase | |||
|---|---|---|---|---|
| Gas | Liquid | Solid | ||
| Dispersion medium |
Gas | No such colloids are known Helium and Xenon are known to be immiscible under certain conditions. |
Liquid aerosol Examples: fog, clouds, mist, hair sprays |
Solid aerosol Examples: smoke, ice cloud, atmospheric particulate matter |
| Liquid | Foam Example: whipped cream, shaving cream |
Emulsion Examples: milk, mayonnaise, hand cream; latex |
Sol Examples: pigmented ink, blood |
|
| Solid | Solid foam Examples: aerogel, styrofoam, pumice |
Gel Examples: agar, gelatin, jelly |
Solid sol Example: cranberry glass |
|
Images for kids
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SEM image of a colloid.
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Brownian motion of 350 nm diameter polymer colloidal particles.
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Measurement principle of multiple light scattering coupled with vertical scanning
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Aerogel
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Jello cubes
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Colloidal silica gel with light opalescence
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Whipped cream
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Mist
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Tyndall effect in an opalite: it scatters blue light making it appear blue from the side, but orange light shines through; opal is a gel in which water is dispersed in silica crystals
See also
In Spanish: Coloide para niños
