9.1-9.4 Science Yearly

current

The rate of the flow of charges. Measured in amperes (A)

amperes

Unit for current (A)

power

A measure of how much energy is used per second. Has the units watts (W) or joules/second (J/s)

watt

Unit for power (W)

voltage

The amount of electrical potential energy that "pushes" the charges around a circuit. Measured in volts (V)

potential difference

Another name for voltage

resistance

How much a substance impedes the flow of charge. Measured in ohms (Ω)

ohms

Unit for resistance (Ω)

circuit

Group of components joined together to create a closed pathway for the flow of charges.

parallel

Type of circuit where there is more than one pathway for the charge

series

Type of circuit where there is only one path for the charges to flow

rheostat

Another name for a variable resistor (a circuit component that can provide varying resistance)

ammeter

Measuring device that is placed in series in a circuit and measures current

voltmeter

Measuring device that is placed in parallel in a circuit and measures potential difference or voltage

multimeter

Device that has more than one meter incorporated in a single unit

battery

Converts chemical potential energy to electrical potential energy (via chemical reactions). Creates direct current (DC).

solar

Pertaining to our Sun (more correctly the star Sol)

fuse

Device that burns out when the current gets too high in order to protect connected devices

switch

Component that can be used to turn a circuit on or off

alternating

Type of current where the electrons oscillate back and forth.

direct

Type of current where the electrons only flow in one direction.

electrical energy

The ability to do electrical work

transformer rectifier

Commonly known as a power pack. Can transform voltages and rectify AC to DC

efficiency

The ratio of the energy output to the energy input. Usually expressed as a percentage.

alternate energy

energy derived from sources that do not use up natural resources or harm the environment e.g. solar, wind etc.

Atomic number

An integer that identifies an element uniquely; equal to the number of protons in an atom's nucleus

Mass number

The sum of the number of neutrons and protons in an atomic nucleus

Element

A substance that cannot be broken down into simpler substances by chemical means

Molecule

A particle consisting of two or more atoms chemically combined

Compound

A substance consisting of two or more different elements chemically combined in a fixed ratio

Proton

A particle in the nucleus of an atom that has a positive charge

Neutron

A particle in the nucleus of an atom that has a neutral charge

Electron

Negatively charged particle that orbits the nucleus of an atom

Nucleus

The small, dense, central region of an atom consisting of protons and neutrons

Group

A vertical column of the Periodic Table where each element has similar chemical properties

Period

A horizontal row of the Periodic Table

Alkali metal

The elements found in Group I of the Periodic Table

Alkaline earth metal

The elements found in Group II of the Periodic Table

Halogen

The elements found in Group VII of the Periodic Table

Noble/inert gas

The gases in Group VIII of the Periodic Table. They are not chemically reactive as they have a full outer shell of electrons

Ion

A charged particle formed by the loss or gain of electrons

Polyatomic ion

A charged particle consisting of many atoms

Valency

A measure of the combining power of a particle with other atoms when it forms chemical compounds or molecules

Electron configuration

A shorthand form of describing the ordered arrangement of a particle's electrons into defined energy levels (shells).

Covalent bond

A type of chemical bond that involves the sharing of electron pairs between atoms

Ionic bond

A type of chemical bond that involves the electrostatic attraction between oppositely charged ions

mono

1

di

2

tri

3

tetra

4

penta

5

hexa

6

hepta

7

octa

8

nona

9

deca

10

Isotope

Atoms with the same number of protons in the nucleus, but a different number of neutrons in the nucleus (different mass numbers)

Transition Metals

A group of metals between Group 3 and 4 of the Periodic Table

Reactants

A substance that takes part in and undergoes a chemical change during a reaction

Products

The substance formed as a result of a chemical reaction

Combustion

A chemical reaction where a fuel combines with oxygen quickly releasing large amounts of energy and forming an oxide of the fuel

Corrosion

A slow chemical reaction where a refined metal reacts with oxygen to form a more stable metal oxide

Precipitation

A chemical reaction where two or more dissolved ionic compounds react to form a solid ionic compound

Neutralisation

A chemical reaction where an acid reacts with a base to form neutral products

Insoluble

Unable to dissolve in a named solvent

Soluble

Able to dissolve in a named solvent

Interference

when two or more waves occupy the same space and combine to create a single resulting wave.

Electromagnetic spectrum

the range of waves that exist in the electric and magnetic fields. These include visible light, radio waves, UV waves, etc.

Transverse

a type of wave where the medium oscillates perpendicular to the direction of the wave's movement.

Diverging

to move away from each other.

Velocity

the combination of an object's change in position and direction.

Rarefaction

the opposite of compression, an area in a longitudinal wave where the average distance between the particles increases.

Ultrasound

the range of sounds that have frequency above human hearing. These are used for imaging for medical uses.

Longitudinal

a type of wave where the medium oscillates parallel to the direction of the wave's movement.

Converging

to move towards each other.

Compression

An area in a longitudinal wave when the average distance between particles is decreased.

Frequency

how many waves pass a point in one second OR how many complete vibrations there are in one second. Measured in Hertz (Hz).

Period

how long it takes for one complete wave to pass. Measured in seconds (s).

Reflection

the bouncing of waves from a surface.

Refraction

the bending of waves as they pass from one medium to another.

Dispersion

the splitting of light into its colours.

Amplitude

the distance from the centre of a wave to the crest (or the centre to the trough)

Wavelength

the distance from crest to crest (or two similar points)

Concave

a lens that dips inwards. This causes light to diverge.

Convex

a lens that bows outwards. This causes light to converge.

Atomic number

An integer that identifies an element uniquely; equal to the number of protons in an atom's nucleus

Mass number

The sum of the number of neutrons and protons in an atomic nucleus

Proton

A particle in the nucleus of an atom that has a positive charge

Neutron

A particle in the nucleus of an atom that has a neutral charge

Electron

Negatively charged particle that orbits the nucleus of an atom

Nucleus

The small, dense, central region of an atom consisting of protons and neutrons

Nuclei

Plural of nucleus

Nuclear

Relating to the atomic nucleus

Nucleon

Any particle found inside the nucleus i.e. protons and neutrons

Isotope

Atoms of the same element containing different numbers of neutrons

Radioactive

A substance that undergoes decay by a nuclear reaction to become more stable

Radioisotope

An isotope of an element that has an unstable nucleus and emits radiation during its decay to a stable form

Alpha (α) particle

A particle consisting of two protons and two neutrons bound together; identical to a helium nucleus

Beta (β) particle

A high energy electron ejected from the nucleus during β radioactive decay. This electron is formed by the decay of a neutron into a proton and an electron.

Gamma (γ) radiation

The highest energy radiation on the electromagnetic spectrum. Released by some radioactive nuclei after alpha or beta decay has already occurred.