Page 63 - Curriculum Visions Dynamic Book

PRIMARy COLOuRS: A set of colours from which all others can be made.
In transmitted light they are red, blue, and green.
PROTEIN: Substances in plants and animals that include nitrogen.
PROTON: A positively charged particle in the nucleus of an atom that balances out the charge of the surrounding electrons.
quENCH: To put into water in order to cool rapidly.
RADIATION: The transmission of energy from one body to another without any contribution from the intervening space. Contrast with CONVECTION and CONDuCTION
RADIOACTIVE: A substance that spontaneously emits energetic particles.
RARE EARTHS: Any of a group of metal oxides that are found widely throughout the Earth’s rocks, but in low concentrations. They are mainly made up of the elements of the lanthanide series of the periodic table of the elements.
RAW MATERIAL: A substance that has not been prepared, but that has an intended use in manufacturing.
RAy: Narrow beam of light.
RAyON: An artificial fibre made from
natural cellulose.
REACTION (CHEMICAL): The recombination of two substances using parts of each substance.
REACTIVE: A substance that easily reacts with many other substances.
RECyCLE: To take once used materials and make them available for reuse.
REDuCTION, REDuCING AGENT: The removal of oxygen from or the addition of hydrogen to a compound.
REFINING: Separating a mixture into the simpler substances of which it is made, especially petrochemical refining.
REFRACTION: The bending of a ray
of light as it passes between substances
of different refractive index (light-bending properties).
REFRACTORy: Relating to the use of a ceramic material, especially a brick, in high-temperature conditions of, for example, a furnace.
REFRIGERANT: A substance that, on changing between a liquid and a gas, can absorb large amounts of (latent) heat from its surroundings.
REGENERATED FIBRES: Fibres that have been dissolved in a solution and then recovered from the solution in a different form.
REINFORCED FIBRE: A fibre that is mixed with a resin, for example, glass- reinforced fibre.
RESIN: A semi-solid natural material that is made of plant secretions and often yellow-brown in colour. Also synthetic
materials with the same type of properties. Synthetic resins have taken over almost completely from natural resins and are available as thermoplastic resins and thermosetting resins.
RESPIRATION: The process of taking in oxygen and releasing carbon dioxide in animals and the reverse in plants.
RIVET: A small rod of metal that is inserted into two holes in metal sheets and then burred over at both ends in order to stick the sheets together.
ROCk: A naturally hard inorganic material composed of mineral particles or crystals.
ROLLING: The process in which metal is rolled into plates and bars.
ROSIN: A brittle form of resin used in varnishes.
RuST: The product of the corrosion of iron and steel in the presence of air and water.
SALT: Generally thought of as sodium chloride, common salt; however, more generally a salt is a compound involving a metal. There are therefore many “salts” in water in addition to sodium chloride.
SAPWOOD: The outer, living layers of the tree, which includes cells for the transportation of water and minerals between roots and leaves.
SATuRATED: A state in which a liquid can hold no more of a substance dissolved in it.
SEALANTS: A material designed to stop water or other liquids from penetrating into a surface or between surfaces. Most sealants are adhesives.
SEMI-CONDuCTOR: A crystalline solid that has an electrical conductivity part
way between a conductor and an insulator. This material can be altered by doping to control an electric current. Semi-conductors are the basis of transistors, integrated circuits, and other modern electronic solid- state devices.
SEMI-PERMEABLE MEMBRANE: A thin material that acts as a fine sieve or filter, allowing small molecules to pass, but holding back large molecules.
SEPARATING COLuMN: A tall glass tube containing a porous disk near the base and filled with a substance such as aluminium oxide that can absorb materials on its surface. When a mixture passes through the columns, fractions are retarded by differing amounts so that each fraction is washed through the column in sequence.
SEPARATING FuNNEL: A pear-shaped glass funnel designed to permit the separation of immiscible liquids by simply pouring off the more dense liquid from the bottom of the funnel, while leaving the less dense liquid in the funnel.
SHAkES: A defect in wood produced by the wood tissue separating, usually parallel to the rings.
SHEEN: A lustrous, shiny surface on a yarn. It is produced by the finishing process or may be a natural part of the yarn.
SHEET-METAL FORMING: The process of rolling out metal into sheet.
SILICA: Silicon dioxide, most commonly in the form of sand.
SILICA GLASS: Glass made exclusively of silica.
SINTER: The process of heating that makes grains of a ceramic or metal a solid mass before it becomes molten.
SIzE: A glue, varnish, resin, or similar very dilute adhesive sealant used to block up the pores in porous surfaces or, for example, plaster and paper. Once the size has dried, paint or other surface coatings can be applied without the coating sinking in.
SLAG: A mixture of substances that are waste products of a furnace. Most slag are mainly composed of silicates.
SMELTING: Roasting a substance in order to extract the metal contained in it.
SODA: A flux for glassmaking consisting of sodium carbonate.
SOFTWOOD: Wood obtained from a coniferous tree.
SOLID: A rigid form of matter that maintains its shape regardless of whether or not it is in a container.
SOLIDIFICATION: Changing from a liquid to a solid.
SOLuBILITy: The maximum amount of a substance that can be contained in a solvent.
SOLuBLE: Readily dissolvable in a solvent. SOLuTION: A mixture of a liquid (the
solvent) and at least one other substance of lesser abundance (the solute). Like all mixtures, solutions can be separated by physical means.
SOLVAy PROCESS: Modern method of manufacturing the industrial alkali sodium carbonate (soda ash).
SOLVENT: The main substance in a solution.
SPECTRuM: A progressive series
arranged in order, for example, the range of colours that make up visible light as seen in a rainbow.
SPINNERET: A small metal nozzle perforated with many small holes through which a filament solution is forced. The filaments that emerge are solidified by cooling and the filaments twisted together to form a yarn.
SPINNING: The process of drawing out and twisting short fibres, for example, wool, and thus making a thread or yarn.
SPRING: A natural flow of water from the ground.
STABILIzER: A chemical that, when added to other chemicals, prevents further reactions. For example, in soda lime glass the lime acts as a stabilizer for the silica.
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