Page 61 - Curriculum Visions Dynamic Book

GROuNDWATER: Water that flows naturally through rocks as part of the water cycle.
GuM: Any natural adhesive of plant origin that consists of colloidal polysaccharide substances that are gelatinous when moist but harden on drying.
HARDWOOD: The wood from a nonconiferous tree.
HEARTWOOD: The old, hard, nonliving central wood of trees.
HEAT: The energy that is transferred when a substance is at a different temperature than that of its surroundings.
HEAT CAPACITy: The ratio of the heat supplied to a substance compared with the rise in temperature that is produced.
HOLOGRAM: A three-dimensional image reproduced from a split laser beam.
HyDRATION: The process of absorption of water by a substance. In some cases hydration makes a substance change colour, but in all cases there is a change in volume.
HyDROCARBON: A compound in which only hydrogen and carbon atoms are present. Most fuels are hydrocarbons, for example, methane.
HyDROFLuORIC ACID: An extremely corrosive acid that attacks silicate minerals such as glass. It is used to etch decoration onto glass and also to produce some forms of polished surface.
HyDROGEN BOND: A type of attractive force that holds one molecule to another. It is one of the weaker forms of intermolecular attractive force.
HyDROLySIS: A reversible process of decomposition of a substance in water.
HyDROPHILIC: Attracted to water. HyDROPHOBIC: Repelled by water.
IMMISCIBLE: Will not mix with another substance, for example, oil and water.
IMPuRITIES: Any substances that are found in small quantities, and that are not meant to be in the solution or mixture.
INCANDESCENT: Glowing with heat, for example, a tungsten filament in a light bulb.
INDuSTRIAL REVOLuTION: The time, which began in the 18th century and continued through into the 19th century, when materials began to be made with the use of power machines and mass production.
INERT: A material that does not react chemically.
INORGANIC: A substance that does not contain the element carbon (and usually hydrogen), for example, sodium chloride.
INSOLuBLE: A substance that will not dissolve, for example, gold in water.
INSuLATOR: A material that does not conduct electricity.
ION: An atom or group of atoms that has gained or lost one or more electrons and so developed an electrical charge.
IONIC BONDING: The form of bonding that occurs between two ions when the ions have opposite charges, for example, sodium ions bond with chloride ions to make sodium chloride. Ionic bonds are strong except in the presence of a solvent.
IONIzE: To change into ions. ISOTOPE: An atom that has the same
number of protons in its nucleus, but that has a different mass, for example, carbon 12 and carbon 14.
kAOLINITE: A form of clay mineral found concentrated as china clay. It is the result of the decomposition of the mineral feldspar.
kILN: An oven used to heat materials. Kilns at quite low temperatures are used to dry wood and at higher temperatures
to bake bricks and to fuse enamel onto the surfaces of other substances. They are a form of furnace.
kINETIC ENERGy: The energy due to movement. When a ball is thrown, it has kinetic energy.
kNOT: The changed pattern in rings in wood due to the former presence of a branch.
LAMINATE: An engineered wood product consisting of several wood layers bonded by a resin. Also applies to strips of paper stuck together with resins to make such things as “formica” worktops.
LATE WOOD: Wood produced during the summer part of the growing season.
LATENT HEAT: The amount of heat that is absorbed or released during the process of changing state between gas, liquid, or solid. For example, heat is absorbed when liquid changes to gas. Heat is given out again as the gas condenses back to a liquid.
LATEx: A general term for a colloidal suspension of rubber-type material in water. Originally for the milky white liquid emulsion found in the Para rubber tree, but also now any manufactured water emulsion containing synthetic rubber or plastic.
LATEx PAINT: A water emulsion of a synthetic rubber or plastic used as paint. See EMuLSION PAINT
LATHE: A tool consisting of a rotating spindle and cutters that is designed
to produce shaped objects that are symmetrical about the axis of rotation.
LATTICE: A regular geometric arrangement of objects in space.
LEHR: The oven used for annealing glassware. It is usually a very long tunnel through which glass passes on a conveyor belt.
LIGHTFAST: A colourant that does not fade when exposed to sunlight.
LIGNIN: A form of hard cellulose that forms the walls of cells.
LIquID: A form of matter that has a fixed volume but no fixed shape.
LuMBER: Timber that has been dressed for use in building or carpentry and consists of planed planks.
MALLEABLE: Capable of being hammered or rolled into a new shape without fracturing due to brittleness.
MANOMETER: A device for measuring liquid or gas pressure.
MASS: The amount of matter in an object. In common use the word weight is used instead (incorrectly) to mean mass.
MATERIAL: Anything made of matter. MATTED: Another word for felted.
See FELTED
MATTER: Anything that has mass and
takes up space.
MELT: The liquid glass produced when a batch of raw materials melts. Also used to describe molten metal.
MELTING POINT: The temperature at which a substance changes state from a solid phase to a liquid phase. It is the same as the freezing point.
METAL: A class of elements that is a good conductor of electricity and heat, has a metallic lustre, is malleable and ductile, and is formed as cations held together by a sea of electrons. A metal may also be an alloy of these elements and carbon.
METAL FATIGuE: The gradual weakening of a metal by constant bending until a crack develops.
MINERAL: A solid substance made of just one element or compound, for example, calcite minerals contain only calcium carbonate.
MISCIBLE: Capable of being mixed. MIxTuRE: A material that can be
separated into two or more substances using physical means, for example, air.
MOLECuLE: A group of two or more atoms held together by chemical bonds.
MONOMER: A small molecule and building block for larger chain molecules or polymers (mono means “one” and mer means “part”).
MORDANT: A chemical that is attracted to a dye and also to the surface that is to be dyed.
MOSAIC: A decorated surface made from a large number of small coloured pieces of glass, natural stone, or ceramic that are cemented together.
MOuLD: A containing shape made of wood, metal, or sand into which molten glass or metal is poured. In metalworking it produces a casting. In glassmaking the glass is often blown rather than poured when making, for example, light bulbs.
NATIVE METAL: A pure form of a metal not combined as a compound. Native
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