Biodegradable - a substance can be broken down into natural elements by micro-organisms and other living things

Builder - a substance softens the water and prevent dirt from going back into the material again

Dacron - a former name of Terylene, also know as PET, a synthetic fibre / polyester made of two monomers: terephthalic acid and ethylene glycol

Detergent - a substance which improves the cleaning properties of water

Emulsifying action - the formation of oil droplets in an oil-water mixture by the action of a detergent

Emulsion - mixture of water and tiny oil droplets formed by the action of a detergent

Hydrophilic - soluble in water but not in grease and oil

Hydrophobic - soluble in grease and oil but not in water

Nylon - a synthetic polymer (polyamide) which contains amide linkage and is made from diamine and dicarboxylic acid

Poly(ethylene terephthalate) (PET) - a polyester formed by the condensation polymerization of terephthalic acid and ethylene glycol

Polyester - synthetic polymers which contain ester linkage and are made from dicarboxylic acids and diols

Saponification - a reaction in which fat or oil (triglycerides) undergoes alkaline hydrolysis to form glycerol and soap

Soapless detergent - a substance for cleaning purpose; made from chemicals derived from petroleum

Soapy detergent - a substance commonly called ‘soaps’ and is made from natural fat and oil

Surface tension - the tension that causes water to bead up on surfaces (such as glass and fabric)

Synthetic detergent - a substance for cleaning purpose; made from chemicals derived from petroleum

Terylene - also know as PET, a synthetic fibre / polyester made of two monomers: terephthalic acid and ethylene glycol

Triglyceride - a compound formed when one glycerol with three hydroxyl groups combines with three molecules of carboxylic acids

Wetting agent - a substance that reduces the surface tension of water, so the water no longer beads up but spreads, and thus wets the surface more thoroughly