Page 64 - Curriculum Visions Dynamic Book

STAPLE: A short fibre that has to be twisted with other fibres (spun) in order to make a long thread or yarn.
STARCHES: One form of carbohydrate. Starches can be used to make adhesives.
STATE OF MATTER: The physical form of matter. There are three states of matter: liquid, solid, and gas.
STEAM: Water vapour at the boiling point of water.
STONEWARE: Nonwhite pottery that has been fired at a high temperature until some of the clay has fused, a state called vitrified. Vitrification makes the pottery impervious to water. It is used for general tableware, often for breakfast crockery.
STRAND: When a number of yarns are twisted together, they make a strand. Strands twisted together make a rope.
SuBSTANCE: A type of material including mixtures.
SuLPHIDE: A compound that is composed only of metal and sulphur atoms, for example, PbS, the mineral galena.
SuPERCONDuCTORS: Materials that will conduct electricity with virtually
no resistance if they are cooled to temperatures close to absolute zero (–273°C).
SuRFACE TENSION: The force that operates on the surface of a liquid, and that makes it act as though it were covered with an invisible elastic film.
SuRFACTANT: A substance that acts on a surface, such as a detergent.
SuSPENDED, SuSPENSION: Tiny particles in a liquid or a gas that do not settle out with time.
SyNTHETIC: Something that does
not occur naturally but has to be manufactured. Synthetics are often produced from materials that do not
occur in nature, for example, from petrochemicals. (i) Dye – a synthetic dye is made from petrochemicals, as opposed to natural dyes that are made of extracts of plants. (ii) Fibre – synthetic is a subdivision of artificial. Although both polyester and rayon are artificial fibres, rayon is made from reconstituted natural cellulose fibres and so is not synthetic, while polyester
is made from petrochemicals and so is a synthetic fibre.
TANNIN: A group of pale-yellow or light- brown substances derived from plants that are used in dyeing fabric and making ink. Tannins are soluble in water and produce dark-blue or dark-green solutions when added to iron compounds.
TARNISH: A coating that develops as
a result of the reaction between a metal and the substances in the air. The most common form of tarnishing is a very thin transparent oxide coating, such as occurs on aluminium. Sulphur compounds in the air make silver tarnish black.
TEMPER: To moderate or to make stronger: used in the metal industry to describe softening hardened steel or cast iron by reheating at a lower temperature
or to describe hardening steel by reheating and cooling in oil; or in the glass industry, to describe toughening glass by first heating it and then slowly cooling it.
TEMPORARILy HARD WATER: Hard water that contains dissolved substances that can be removed by boiling.
TENSILE (PuLLING STRENGTH):
The greatest lengthwise (pulling) stress a substance can bear without tearing apart.
TENSION: A state of being pulled. Compare to compression.
TERRA COTTA: Red earth-coloured glazed or unglazed fired clay whose origins lie in the Mediterranean region of Europe.
THERMOPLASTIC: A plastic that will soften and can be moulded repeatedly into different shapes. It will then set into the moulded shape as it cools.
THERMOSET: A plastic that will set into a moulded shape as it first cools, but that cannot be made soft again by reheating.
THREAD: A long length of filament, group of filaments twisted together, or a long length of short fibres that have been spun and twisted together into a continuous strand.
TIMBER: A general term for wood suitable for building or for carpentry and consisting of roughcut planks.
Compare to LuMBER
TRANSITION METALS: Any of the group of metallic elements (for example, chromium and iron) that belong to the central part of the periodic table of the elements and whose oxides commonly occur in a variety of colours.
TRANSPARENT: Something that will readily let light through, for example, window glass. Compare to translucent, when only some light gets through but an image cannot be seen, for example, greaseproof paper.
TROPOSPHERE: The lower part of the atmosphere in which clouds form. In general, temperature decreases with height.
TRuNk: The main stem of a tree. VACuuM: Something from which all air
has been removed.
VAPOR: The gaseous phase of a substance that is a liquid or a solid at that temperature, for example, water vapour is the gaseous form of water.
VAPORISE: To change from a liquid to a gas, or vapour.
VENEER: A thin sheet of highly decorative wood that is applied to cheap wood or engineered wood products to improve their appearance and value.
VINyL: Often used as a general name for plastic. Strictly, vinyls are polymers derived
from ethylene by removal of one hydrogen atom, for example, PVC, polyvinylchloride.
VISCOSE: A yellow-brown solution
made by treating cellulose with alkali solution and carbon disulphide and used to make rayon.
VISCOuS, VISCOSITy: Sticky. Viscosity is a measure of the resistance of a liquid to flow. The higher the viscosity – the more viscous it is – the less easily it will flow.
VITREOuS CHINA: A translucent form of china or porcelain.
VITRIFICATION: To heat until a substance changes into a glassy form and fuses together.
VOLATILE: Readily forms a gas. Some parts of a liquid mixture are often volatile, as is the case for crude oil. This allows them to be separated by distillation.
WATER CyCLE: The continual interchange of water between the oceans, the air, clouds, rain, rivers, ice sheets, soil, and rocks.
WATER VAPOuR: The gaseous form of water.
WAVELENGTH: The distance between adjacent crests on a wave. Shorter wavelengths have smaller distances between crests than longer wavelengths.
WAx: Substances of animal, plant, mineral, or synthetic origin that are similar to fats but are less greasy and harder. They form hard films that can be polished.
WEAVING: A way of making a fabric by passing two sets of yarns through one another at right angles to make a kind of tight meshed net with no spaces between the yarns.
WELDING: Technique used for joining metal pieces through intense localized heat. Welding often involves the use of a joining metal such as a rod of steel used to attach steel pieces (arc welding).
WETTING: In adhesive spreading, a term that refers to the complete coverage of an adhesive over a surface.
WETTING AGENT: A substance that is able to cover a surface completely with a film of liquid. It is a substance with a very low surface tension.
WHITE GLASS: Also known as milk glass, it is an opaque white glass that was originally made in Venice and meant to look like porcelain.
WROuGHT IRON: A form of iron that is relatively soft and can be bent without breaking. It contains less than 0.1% carbon.
yARN: A strand of fibres twisted together and used to make textiles.
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