Solids, liquids and gases
The The use of the arrangement and movement of particles to describe solids, liquids and gases. of Sub-atomic particles and anything made from them, such as atoms and molecules, are matter. Energy and forces are not matter. is a model that describes the arrangement, movement and The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. of A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules. in a substance. The model is used to explain the A description of the appearance of a substance or how it acts without involving chemical reactions. For example, state, melting point, conductivity, etc. of solids, liquids and gases.
Learn more on states of matter in this podcast.
Listen to the full series on BBC Sounds.
Particle arrangement and movement
The table below shows a comparison of the same substance in three different states.
In terms of relative energy, gas particles have the most energy, solid particles have the least energy and liquid particles are somewhere in between. (All compared at the same temperature.)
The particles in the diagrams could be The smallest part of an element that can exist. or A collection of two or more atoms held together by chemical bonds. or Electrically charged particle, formed when an atom or molecule gains or loses electrons., depending on the type of substance, eg ionic compounds, simple molecules, giant molecules and metals.
Explaining properties
Solids:
- have a fixed volume and a fixed shape
- cannot flow, because their particles cannot move from place to place
- cannot be Made smaller by squeezing together., because their particles are close together and have no space to move into
Liquids:
- have a fixed volume but no fixed shape
- can flow and take the shape of their container, because their particles can move around each other
- cannot be easily compressed, because their particles are close together and have no space to move into
Gases:
- have no fixed shape or volume
- can flow and completely fill their container, because their particles can move quickly in all directions
- can be compressed, because their particles are far apart and have space to move into
