SCIENCE

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noble gases: Elements with zero valency. They form group 0 in the periodic table and are non-reactive.
gravity: The attraction that all bodies have for one another.
chemical (empirical) formula: The ratio of elements in a substance. For example: the chemical formula of common salt is NaCl, sodium and chlorine in a ratio of 1:1.
specific heat: The heat capacity of a body.
refraction: The deflection of a wave as it passes from one medium to another, eg through a lens.
elasticity: The ability of a body to regain its original shape after deformation.
resistance: Opposition to current flow in a conductor.
protons: Positively charged particles forming part of atomic nuclei. 3 quarkhadrons.
compound: A substance containing more than one element.
absolute zero: The lowest theoretical temperature (0K = -273.16°C) where all molecular activity ceases.
evolution: Natural selection, the survival of the fittest, is the driving force behind evolution and is measured by a species viability and fecundity.
viscosity: The internal friction of a fluid, thick fluids have a high viscosity and thin fluids low.
electrons: Negatively charged atomic particles.
simple harmonic motion: A repeating motion about a central equilibrium point (pendulum, weighted spring).
photo-synthesis: The conversion of water and carbon-dioxide by plants into glucose and oxygen. Light is used as an energy source.
alcohol: Organic compound used in gums, resins, dyes and perfumes. Fermentation produces ethanol not alcohol.
chemical reaction: The transformation of substances by the rearrangement of their atoms.
half-life: The time taken for the level of radioactivity in an element to halve.
isomeric structure: The shape of a molecule. The isomeric structure is determined by the order in which the atoms are bonded together.
organelles: Specialized organs within cells.
phase changes: Freezing or boiling.
atomic weight: The average weight of an atom.
fission: Splitting the nucleus of an atom into smaller units.
mesons: Two quarkhadrons, the product of radioactive decay.
chromosomes: DNAmolecules that contain the set of instructions required to build and maintain cells.
atoms: Composite particles of protons, neutrons and electrons. The smallest part of a substance that can take part in a chemical reaction. Click here for more information.
strain: The deformation of a body under an applied load.
valency: A measure of the reactivity of an element.
relative atomic mass (RAM): The mass of an atom relative to one atom of carbon. Carbon has a RAM of 12.
Laws of Themodynamics: 1. The amount of energy in the universe is fixed. It cannot be created or destroyed only changed from one state to another.
halogen: Highly reactive gases forming group 7 of the periodic table.
speciation: A group of organisms that are able to interbreed all belong to the same species. It follows then that organisms that are unable to interbreed belong to separate species.
resonance: A state where the natural frequency of a body equals an applied frequency.
evaporation: The change of state of a substance from a liquid to a gas below its boiling point.
fluid: A liquid or gas.
isomer: Chemical compounds with the same composition but different shapes.
moment: A rotating effect. See torque.
bond: A chemical link between atoms.
reactants: The substances that take part in a chemical reaction.
organic compounds: Substances that contain Carbon.
viability: The ability to survive to adulthood.
base: A compound that yields hydroxide (OH- ) ions when in aqueous solution. Bases have a bitter taste, feel greasy and turn red litmus blue.
monomers: Small molecules that link together to form a polymer.
kinetic energy: The energy possessed by a body in motion.
DNA: Deoxyribonucleic acid: Twisted helical polymer chains. See chromosomes.
exothermic reaction: A reaction from which heat is lost eg: combustion.
latent heat: The amount of energy required to change a solid to a liquid or liquid to a gas.
neutrons: Particles with zero charge forming part of an atomic nuclei. 3 quarkhadrons.
entropy: The state of disorder in a thermodynamic system: the more energy the higher the entropy.
proteins: Amino acid polymers with specific biological functions, especially the growth, regeneration and repair of cells.
temperature: How hot one body is when compared to another.
baryon: A three quark hadron. The most common baryons are protons and neutrons.
diffraction: The deviation in the path of a wave that encounters the edge of an obstacle.
crystal: Solid substance with a regular geometirc arrangement of atoms.
standard model: The organization and relationships between fundamental particles.
heat: The internal energy of a body (substance).
energy: The capacity to do work. Work is done by transferring energy from one form to another. For example the chemical energy in a fuel is converted to thermal energy as it burns. See also Laws of Thermodynamics.
boiling point: The temperature at which a liquid turns to a vapour.
pH Scale: The strength of acids and bases. Pure water has a pH value of 7, acids have a lower value and bases higher.
ionic bond: An bond formed by the electro-magnetic attraction between ions of opposite charge.
convection: Heat transfer through the movement of a fluid, eg: warm air rising.
weight: The gravitational force exerted on a mass.
capacitance: The ability to store an electric charge.
activation energy: The energy required to initiate a chemical reaction.
cytosol: Jelly-like substance within cells.
acceleration: Rate of change of velocity.
electromagnetic waves: Waves with both an electric and magnetic component. They are: radio, micro, infra-red, visible light, ultraviolet, X and gamma rays.
momentum: The product of mass times velocity. Momentum is conserved in any system of particles.
lens: Light modifier. Convex lenses focus and concave lens diffuse light waves.
field: A region in space that is defined by a vector function. Common fields are: gravitational, electric and magnetic.
photons: Fundamental quantum particles. It is the interaction of photons with other particles that drives the universe.
atomic number: The number of protons in an atom..
charge: The amount of unbalanced electricity in a system. Either positive or negative.
polymerisation: The repetitive bonding of small molecules (monomers) to produce large molecules (polymers).
inheritance: The features of an organism are determined by a set of chromosomes. These originate in the parents and are passed on to an offspring during fertilisation. It follows then that since chromosomes are inherited, all the features of an organism must be inherited.
respiration: The production of energy by the oxidisation of glucose.
magnet: A body which produces a magnetic field. All magnets are di-pole and follow the rule that like poles repel and unlike poles attract.
vector: A quantity that is determined by its magnitude and direction: forces and fields (see scalar).
metals: Elements characterised by their opacity, malleability and thermal and electrical conductivity.
chemical equation: The mathematical representation of a chemical reaction.
acid: A compound that yields hydrogen ions (H+) when in aqueous solution. Acids have a sour taste and turn blue litmus red.
products: The substances produced in a chemical reaction.
hadrons: Quark composites: mesons and baryons. Protons and neutrons are the most common hadrons.
gametes: Sex cells (spermatozoa or ova) that carry the genes donated by each parent.
carbohydrates: The major energy source within plants and animals: sugars, starches and glucose polymers.
amino acids: Carbon, hydrogen, oxygen and nitrogen compounds the composition of which are determined by genes.
velocity: The rate of change of distance with respect to time.
molecule: A group of atoms bonded together. It is the smallest part of a substance that retains the chemical properties of the whole.
allele: Gene variant
cation: A positive ion.
chain reaction: Polymerisation initiated by the bonding of a free radical with a monomer.
light: The visible part of the electromagnetic spectrum: red, orange, yellow, green, blue, indigo and violet. White light is a combination of all the above colours.
reproduction: Reproduction is the process by which a new organism is produced. The first stage in the production of any organism is the fertilisation of an ova by spermatozoa (or spores on the case of plants). Fertilisation produces a single cell called a zygote which contains all the information required to build the adult organism. The progression (growth) from zygote to adult is achieved through cell division.
biosynthesis: The production of cellular material.
molecular formula: The number and types of atom in a molecule. For example the molecular formula of methane is CH4, one atom of carbon and four atoms of hydrogen.
uncertainty: It is impossible to know exactly where something is and where it is going. This is a fundamental law of nature has a major effect on quantum theory.
electric current: A flow of electrons through a conductor, the size of the current is proportional to the rate of electron flow.
alkali: A base that is soluble in water.
gauge bosons: Particles that mediate the transfer of energy between other particles: protons, gravitons, W and Z particles.
potential difference: The voltage difference between two points. Electricity flows from a high to low level of potential.
alloy: A substance formed by the combination of two or more elements, at least one of which must be a metal.
isotope: An element that has more or less neutrons than normal. Many isotopes are radioactive.
ozone: An isotope of oxygen that blocks ultra-violet radiation. Normally found in the stratosphere.
relativity: The relative values of time, motion, mass and energy of a body in motion.
fecundity: The ability to breed.
density: The mass per unit volume in a substance.
torque: The tendency of a body to rotate under an applied force..
genome: The collective noun for a set of genes. The human genome contains 100 000 genes.
nucleus: 1. Organelle containing the chromosomes. 2. That part of an atom containing the protons and neutrons.
special relativity: The observable effects on a body in motion. As velocity increases, time slows down, mass increases and lengths contract.
radioactivity: The spontaneous release of energy from atomic nuclei.
free radical: A highly reactive molecule used to start the production of a polymer chain.
mass: The quantity of matter in a body.
stress: The measure of the force acting on a body.
cell: The smallest independent part of an organism.
friction: The interaction between surfaces: a measure of the resistance felt when sliding one body over another.
coulomb attraction: Electrostatic attraction between bodies of opposite charge
ideal gas: One which obeys the ideal gas law. At low pressures, real gases behave like ideas gases.
catalyst: A substance that reduces the activation energy of a reaction.
enzymes: Biological catalysts, proteins that control specific processes within the body.
polymers: Long chain molecules such as PVC, nylon or DNA produced by the polymerisation of monomers.
gene: A unit of inheritance. A section of DNA. comprising a sequence of four bases: adenine, guanine, cytosine and thymine.
equilibrium: A stable situation in which products and reactants are balanced.
potential energy: Amount of useable energy within a body at rest.
fats: Molecules of fatty acids or glycerol. Used as a food store, insulation and for shock absorption.
carbon: The basic element in all organic compounds.
zygote: A fertilised egg, the fusion of a male and female gamete.
covalent bond: A bond formed between atoms that share electrons.
quarks: Fundamental particles, incapable of independent existence, that combine to form particles such as protons and neutrons.
radiation: 1. Transfer of heat between bodies without a change in the temperature of the intervening medium. 2. Any release of energy from its source.
hydrocarbon: Compounds containing only hydrogen and carbon atoms.
ion: Atom with an unbalanced electrical charge caused by the loss or gain of one or more electrons.
anion: A negative ion.
diffusion: The random movement of molecules within a fluid.
conduction: Heat or electricity transfer through molecular interaction, eg: heat passing along a metal bar.
mitochondria: Organelles that convert glucose into energy.
atomic symbol: The letters representing each of the elements.
quantum theory: The theory that energy can only be absorbed or radiated in discrete values or quanta. All particles are subject to quantum theory.
leptons: Fundamental particles that are relatively non-reactive and capable of an independent existence: electrons, muons, tau particles and neutrinos.
scalar: A quantity that is defined by its magnitude only (ie energy, temperature).
allotrope: Element with more than one natural form.
force: An action (transfer of energy) that will accelerate a body in the direction of the applied force. See Newtons Laws of Motion.
fusion: 1. Change of state of a substance from a solid to a liquid. 2. The joining together of two atomic nuclei.
power: Amount of work done per second.
element: A substance composed of atoms all with the same atomic number. A substance that cannot be split chemically into smaller substances.
inertia: Tendency of a body to remain at rest or move in straight line.
Newtons Laws of Motion: Classical laws which enable the prediction of the path of any object from a grain of sand to entire galaxies.
endothermic reaction: A reaction in which heat is absorbed ie: melting or boiling.
neutralization: A reaction in which the characteristics of an acid or base disappear.
work: The amount of energy transferred to a system.
fundamental particles: Those particles that are not known to contain any smaller components: leptons, quarks and gauge bosons.
electrolyte: An ion solution that is an electrical conductior.

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