The microscopic `tadpoles’ in your washing machine

The secret behind all washing powders is chemical that makes water ‘wetter’. Curiously enough, water left to itself does not `wet’ or spread over things very efficiently This is because of surface tension, phenomenon that causes water to have kind of skin. On ponds, insects run on this skin, which is caused by an inward pull or the top layer of water molecules by the molecules underneath.

The addition of washing powder o liquid to the water weakens the force: between the molecules, and reduces the surface tension. This allows the water to spread more easily and wet things better. In the wash, the wetter water is able to penetrate the fibres of fabric more easily and help to lift off any dirt or grease.

The active ingredient of non-soap detergent is a petroleum derivative, alky benzene, treated with sulphuric acid and caustic soda.

The molecules of the detergent can be thought of as little tadpoles, with a heat and a tail. The heads are attracted to water molecules – they are water-loving (hydro philic) because water molecules are slightly electrically positive while the detergent heads are electrically negative. The tails on the other hand, are water-hating (hydrophobic).

When dirty clothes are put in a detergent solution, the tails of the molecules attach themselves to greasy dirt in the fibres because the tails are chemically similar to grease. They also work their way between the fibres and the dirt and loosen it. The dirt particles, having attracted the tails effectively become coated all over with layer of water-loving heads – like tin: balloons – and float away in the water Agitation of the clothes by the Washing machine helps to shake away the dirt.

Washing powder is a mixture of up to ten or more substances. It contains the, basic detergent and other ingredients including bleach.

Biological washing powders differ from other detergents by containing enzymes which are types of proteins produced b’ plants and animals. The enzymes act a catalysts, or chemical triggers, to help in breaking down protein stains, such a blood, gravy and perspiration. The enzymes actually cause a chemical break down of proteins, whereas normal detergents work physically. Because protein stains are derived from living things the washing powders are called biological