A

Absorber - an absorber does not reflect or transmit particles or radiation that hit it. Aluminium foil is an absorber of alpha particles.  A dark, dull surface is an absorber of infra-red radiation.

Accuracy - is a term that refers to the properties of a measuring instrument. 

Acid - is a substance that disolves in water to form a solution with a pH below 7.  An acid contains hydrogen which can be replaced by a metal to form a salt.  When an acid dissolves in water H+(aq) ions are formed.  A strong acid completely ionises in water and a weak acid only partly ionises.  Common strong acids include hydochloric acid, HCl, sulphuric acid, H2SO4 and nitric acid, HNO3.  A common weak acid is ethanoic acid, CH3COOH.

Acid rain - Sulphur and nitrogen oxides are produced from the burning of fossil fuels.  When they escape into the atmosphe, they form sulphuric and nitric acids.  Thes acids cna have effects on our environment, e.g. erode stonework, lower the pH of lakes and rivers killing our wildlife, and cause damage to trees. 

Air - is a mixture of gases.

Alkali - is a metal oxide or hydroxide (base) that dissolves in water to form a solution iwth a pH greater than 7.  An alkali is neutralised by an acid to form a salt and water.  Common alkalis include sodium hydroxide, NaOH, potassium hydroxide, KOH, calcium hydroxide, Ca(OH)2 and ammonium hydroxide, NH4OH.

Alloy - is a metal made by mixing two or more metals together, e.g. brass ins a mixture of copper and zinc.

Atom - is the smallest particle of an element which can exist.

B

Battery - a battery consists of a number of electrical cells.  These cells are usually connected in series to give a highter voltage than that from a sinlge cell.

C

Circuit - is one or more conducting paths between the two electrodes of a cell or battery of cells.

Concave - describes the shape of a lens or other object where the center is thinner than the outside.

Corrosion - is the wearing away of the surface of a metal by chemical reactions with oxygen and water.  Rusting is one example of corrosion.

Current - is a flow of electric charge.  The current is a metallic conductor is due to a flow of negatively charged electrons. 

D

Dissolving - is the process that occurs when a solute is added to a solvent and the solute disappears.  The particles of the solute fit between the particles of the solvent.  The solute can be recovered by the evaporation process.

E

Earth - is the planet that we inhabit.  In electricity, the term refers to an electrical connection to the Earth.

Ecosystem - is the sum total of all the living organisms and non-living factors in an environment and the way they interact.

Element - is a pur substance made of one kind of atom.  It cannot be split up into anything simpler without losing its characteristics. 

Erode - is to wear away.

Erosion - is the process where rocks are worn away.

Evaporation - is the process in which a liquid changes to a vapour, due to particles leaving the surface of the liquid. 

Explosion - is a very rapid reaction accompanied by a large expansion in gases.

F

G

H

I

Indicator - is a chemical that can show if a substance is acidic or alkaline by changing color.  :ot,is tirms red om acids and blue in alkali.

J

K

L

M

Magnetic - applies to any object or material that is repelled or attracted by a magnet.  Magnetic materials include iron, steel, cobalt and nickel.

Magnetic field - is an area where a magnetic material experiences a force.  Magnetic fields exist around permanent magnets, electromagnets and electric currents.

Melting - is when a solid changes to a liquid at the melting point.

N

Neutron - is an atomic particle found in the nucleus.  It is similar in mass to a proton buth has no charge.

O

P

Planet - is a large body that orbits a star.

Plates - are huge sections of the Earth's crust which float on the mantle.

Pole - in magnetism, the strongest part of a magnet. The pole of a magnet that points towards magnetic North is calle dits North seeking pole.

Proton - is an atomic particle found in the nucleus.  It is similar in mass to the neutron but has a positive charge.

Q

R

Reaction Time - is the time that elapses between an event occurring and aperson responding to the event.

Reflection - is the change in direction when light or other wavemotion rebounds at a boundary between two materials.

Refraction - is the change in speed when light or other wave motions passes from one material into another. The change in speed causes a change in wavelength and may cause a change in direction.

Rusting - is an oxidation process of iron and steel.   Iron and steel rust in the presence of oxygen (air) and water.   Rust is hydrated iron(III) oxide.  Rust damages metal parts so it is important to try to prevent it.  One way is to alloy the iron and steel with other metals which resist rust.  Stainless steel is an alloy of iron wiht other metals such as chromium and nickel.  Tpresence of these other metals protects the stainless steel from corrosion and allows these metals to be used as kitchen sinks and cutlery.

S

Solar System - is a star and all the objects that orbit it.

Solution - is the mixture formed when a solute dissoves in a solvent.

Star - is an astronomical object that generates energy due to nuclear fusion.  A star gives out light and/or other forms of electromagnetic radiation.

Static Electricity - is an unbalanced charge that is not moving.  A common cause of static electricit is the transfer of electrons when two objects are rubbed together.  The object that gains electrons becomes charged negatively while the object that loses electrons becomes charged positively.

Sun - is the Earth's star.

T

Temperature - is a measure of how hot an object is.

U

Universe - is everything that exists.

V

W

X

Y

Z

 

 

 

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