Glossary of terms you may come across in Science – Part 2
Atom
The smallest part of an element. All atoms contain
protons and electrons.
Chemical Change
A change which makes a new substance, e.g. coal
burning.
Combustion
The reaction occurring when a substance burns in
Oxygen, giving out heat energy.
Compound
A substance made when 2 or more elements join
together chemically, e.g. Oxygen and Hydrogen
combining to form water.
Conduction
The process by which heat transfers through the
atoms of a solid.
Convection
The process by which heat is carried around a gas or
liquid by energetic atoms, making convection currents.
Remember ‘hot air rises’.
Displacement
When one element takes the place (‘displaces’)
another in a chemical reaction.
Distillation
A method of separating liquids, by boiling them off at
different temperatures.
Electrolysis
Process which uses electricity to break down
compounds.
Electron
A tiny particle with a negative charge.
Element
A substance made of only one type of atom.
Equation (chemical)
A short, accurate way of describing the changes
taking place in a chemical reaction.
Filtration
A process used to separate un-dissolved solids from
liquids.
Fossil Fuels
Energy resources made millions of years ago from the
remains of animals or plants.
Coal, Oil, Gas, Peat.
Gas
A substance that is light and easily squashed. Its
particles move quickly in all directions (‘diffuse’), and
it fills the shape of its container.
Heat
Form of energy that causes atoms to vibrate or move.
Liquid
Substance whose particles are free to move around.
It fills the shape of its container.
Metal
An element which is normally shiny and a good
conductor of heat and electricity. E.g. Copper, Iron,
Gold. About 75% of all elements are metals.
Mixture
A substance made when some elements or compounds
are mixed (not joined) together.
Molecule
A group of atoms joined together.
Noble Gases
A group of 6 gases which do not react with other
elements to form compounds.
Non Metal
An element which is not a metal, and generally does
not conduct electricity, e.g. Oxygen, Silicon, Iodine.
About 25% of elements are non-metals.
Non Renewable Energy
Energy sources that, once they are used, will not be
Resources
replaced, e.g. fossil fuels (coal, oil, gas).
Oxidation
A reaction where Oxygen is added to a substance.
Periodic Table of
A chart showing all known elements and their
Elements
properties. First put together by Dmitri Mendeleev.
Currently 112 elements have been discovered,
Physical Change
A change where no new substance is made, the
substance just changes state e.g. water freezing to
become ice.
Product
A substance made as a result of a chemical reaction.
Radiation
Energy being transferred around by rays of light, X
Rays, Infra-Red etc. Can travel through a vacuum.
Reaction
A chemical change which makes a new substance.
Reactivity Series
A list of elements in order of their reactivity (how
easily they react with other substances). Most
reactive is at the top of the list.
Reduction
A reaction where oxygen is removed, e.g. Copper
Oxide is reduced to Copper.
Renewable Energy
Energy sources that do not get used up, e.g. solar,
Resources
wind, hydro etc.
Temperature
How hot or cold something is. A measure of the heat
energy contained within it, measured using a
thermometer, in degrees Celsius (˚C)
Thermal Energy
Another name for heat energy