Examples of Colloids

Several everyday phenomena are explained by colloid chemistry. (i) The blue colour of the sky: minute dust particles together with tiny water droplets dispersed in air scatter blue light preferentially, and that scattered blue light is what reaches our eyes, making the sky appear blue. (ii) Blood: blood is a colloidal dispersion of plasma proteins and antibodies in water, and at the same time it is also a suspension of blood cells and platelets in that same watery plasma. (iii) Soils: fertile soils are colloidal in nature, with humus acting as a protective colloid; a soil's colloidal character is what lets it adsorb moisture and nourishing (nutrient) materials, which is central to its fertility. (iv) Fog, mist and rain: mist is caused by small water droplets dispersed in air, while fog forms specifically when there is a temperature difference between the ground and the air above it -- a layer of dust-laden air cool …