Glossary

A

alloy
Alloys, often mistakenly called metals, are mixtures that contain at least one metal.

atmosphere
the atmosphere is the layer of gases that rise from the ground to the edge of space.
B

biodegradable
Materials that can be broken down by sun light, bacteria, fungus, water or animals. Non-biodegradable is the opposite.

boiling
When a liquid is heated and becomes a gas.

boiling point
This is the temperature at which a liquid becomes a gas. It is the same temperature that a gas condenses to a liquid.

brittle
Can break easily.
C

caustic
Caustic is another name for alkali. It is the opposite of acid. It is damaging to skin and some materials.

chemical resistant
Materials that are not changed by being with other chemicals e.g. gold does not corrode when put in water.

clear
Light can pass through. See-through, transparent.

colourless
Having no colour.

condensing
When a gas or vapour cools and becomes a liquid.

conduct
A material conducts when either heat or electricity passes through it.

conductor
A conductor lets either heat or electricity passes through it.

conductor of electricity
Conductors are materials that let heat or electricity through them. Electrical conductors.

conductor of heat
Conductors are materials that let heat through them. They are also known as thermal conductor.

conducts
A material conducts when either heat or electricity passes through it.

corrode
Materials corrode when they change due to water and air being present.

corrodes
A material corrodes when they change due to water and air being present

corrosion
Corrosion occurs when a material changes due to water or air being present. Rusting is a form of corrosion.

corrosive
Examples of corrosive materials are chemicals such as acid and caustic soda. They are reactive. They can also damage eyes, skin and other materials.
D

dense
Small volumes of dense materials are heavy. Metals like lead are very dense. Gases, like air, are not very dense. Dense materials have a lot of ‘stuff’ in very small space/volume.

density
Density is a way of calculating how much space heavy or light materials take up. Dense materials are heavy when there is not much of them. Low density materials do not weigh a great deal when there is a lot of it.

discolour
A material discolours when the colour changes to something else, the colour fades or the colour is lost.

dissolve
When a material such as salt is mixed with water until it cannot be seen the salt is said to dissolve.

ductile
Ductile materials can be easily? forced and made into pipes/tubes or thinner rods. e.g. a metal like copper can be hammered/drawn into a thin wire.

durable
Long lasting.
E

electrical insulator
Materials that do not let electricity pass through them.

elements
An element is a simple chemical. All elements are listed on the periodic table.

evaporating
When a liquid turns to a vapour/gas.

evaporation
Evaporation is when a liquid dries up and becomes a vapour.

exothermic
exothermic describes heat being produced when a material reacts becoming something else.
F

flammable
Flammable materials burn. Flammable is the same as inflammable.

flexible
Bendy.

freezing
When a liquid cools and becomes a solid.
G

gas
Particles in a gas are far apart so they are easy to walk through. Gases are low density. Gases are made by heating liquids above their boiling point.
H

hardness
Hard materials are hard to scratch.
I

insoluble
Insoluble materials do not dissolve when mixed with water.

insulator
Materials that do not let heat or electricity easily pass through them.

irreversible
Irreversible changes do not change back to the way they were.
L

lightweight
Lightweight materials are low density. Low density material does not weigh a great deal when there is a lot of it.

liquid
Particles in a liquid are close together and stick weakly to each other. Walking through a liquid like water is harder than walking through air.
M

malleable
Can be shaped when a force is applied eg like squeezing modelling clay.

melting
When a solid is heated and it becomes a liquid.

melting point
The temperature at which a solid become a liquid or a liquid becomes a solid.

metal
Metals are solids that easily conduct electricity. They can be shiny. Alloys such as bronze, brass and steel are often mistakenly called metals.

mixture
A mixture is made when two or more materials are mixed up but do not change. Sand and salt can make a mixture.

molten
Molten materials are solids which have been heated until they become a liquid. e.g. molten iron is iron that is so hot it is a liquid.
N

non-conductor
A non-conductor does not let heat or electricity through it. Insulator is another word for non-conductor.
O

odourless
Having no smell.

opalescence
The property of something having a milky brightness when lit.

opaque
Not able: to be seen through. Not transparent. Not see-through.
P

plastic
A group of materials that are insulators. They can be coloured. There are thousands of different plastics. The scientific name for plastics is polymer.

polymer
The scientific name for a plastic.

porous
Porous materials contain tiny holes and so would soak up water. A sponge is porous.

powder
Powders are made when a solid is finely ground up into very small pieces.
R

reflect
When light bounces off an object the object is said to reflect. Mirrors and shiny metals reflect light.

resistant
Is not affected by force. See also chemically (above says 'resistant').

reversible
When things change back. E.g. Water freezes to ice and ice melts to become liquid water.

rust
Rust is formed when iron or steel changes and becomes weaker because of air and water.

rusting
When iron corrodes it is called rusting. Only iron and steel - will rust? Other metals are said to corrode.
S

see through
Light can pass throgh. Examples include glass. It is not the same as colourless.

shatter
Shatter means breaks into pieces.

shatter resistant
Does not easily break or shatter when hit.

shiny
Materials that reflect light.

solid
Particles in a solid are close together and stuck well to each other. Walking through a solid is impossible. Solids when heated can turn into liquids.

solution
A solution is made when water dissolves something. Salt dissolving in water makes a solution of salt called saltwater.

sonorous
Materials that make a noise when hit.

state changes
These are when a solid becomes a liquid, a liquid becomes a gas, a gas becomes a liquid and liquid becomes a solid.

strength
Strength is a measure of how strong something is. A high strength material would be hard to break.

stretchy
Returns to original shape once force is released.

strong
Strong materials are hard to break.
T

tasteless
Having no taste.

thermal Insulator
Materials that do not let heat pass through them.

tough
Hard wearing: Not easily cut or worn down.

translucent
Letting some but not all, light through.

transparent
Letting all light through. Clear and see-through.
V

vapour
Another name for gas but one that is cooler than the boiling point.
W

waterproof
Materials that are not affected by water or do not let water in. Also called water-resistant