THE SUBSTANCE OF THE UNIVERSE
WARM UP
• In your opinion, which of the following things are ’matter’ or ’non-matter’?
air • clouds • energy • gravity • heat • iron • love • Mars • microwaves • person • rainbow • reflections • rock • sound • spider • the Sun • sunlight • time • tree • water
Definition of matter
Everything that has mass and takes up space is matter1; however, there are some things that do not consist of matter. All substances consist of matter but any type of energy or any abstract concept is something that is not matter.
The basic chemical building blocks of matter are elements. A chemical element is a material which cannot be broken down or changed into another substance using chemical means.
DO
1 Look up in the dictionary and find two more meanings of the word ‘matter’.
States of matter
Four states of matter can be observed in everyday life: solid, liquid, gas and plasma. The different states of matter have different physical properties.
A solid has a rigid shape and a fixed volume that does not change much with temperature.
A liquid has a fixed volume but no rigid shape and it takes the shape of its container. Its volume may alter with changes in temperature and pressure. Liquids, like solids, cannot be compressed.
A gas has neither definite volume nor shape as it expands to fill its container completely. Its volume is very sensitive to temperature and pressure.
Plasma consists of highly-charged particles with extremely high kinetic energy. While plasma is not a common state of matter on Earth, man-made plasmas are everywhere.
Many other states of matter are known to exist only in extreme environments, such as BEC (Bose-Einstein Condensates)1, referred to as 'the fifth state of matter'.
MORE
1 Of the five states matter can be in, the Bose-Einstein condensates are perhaps the most mysterious. They weren't created in the laboratory until the 1990s. Plasma was identified by William Crookes in 1879.
Phase changes
When specific physical conditions – such as temperature, pressure, and other physical forces – change, matter can move from one phase to another:
- solids may melt into liquids (fusion / melting)
- solids may sublimate into gases (sublimation)
- liquids may vaporise into gases (vaporisation / boiling)
- liquids may freeze into solids (freezing)
- gases may condense into liquids (condensation)
- gases may deposit into solids (deposition).
