Topic Menu

Cyber-chess a chess instruction site

Physics 8463 - 4.3 Particle model of matter

4.3.1 Changes of state and the particle model

Helpful pages
4.3.1.1 Density of materials

The density of a material is defined by the equation:

density = mass/volume

ρ = m /V

This equation is NOT given on the Physics equation sheet - you need to know it, what the letters mean and are measured in!

ρ = density, in kilograms per metre cubed, kg/m3

m = mass, in kilograms, kg

V = volume, in metres cubed, m3

The particle model can be used to explain

the different states of matter

differences in density.

You should be able to recognise/draw simple diagrams to model the difference between solids, liquids and gases.

You should be able to explain the differences in density between the different states of matter in terms of the arrangement of atoms or molecules.

Required practical activity 5:

Use appropriate apparatus to make and record the measurements needed to determine the densities of regular and irregular solid objects and liquids.

Volume should be determined from the dimensions of regularly shaped objects, and by a displacement technique for irregularly shaped objects.

Dimensions to be measured using appropriate apparatus such as a ruler, micrometer or Vernier callipers.

 
4.3.1.2 Changes of state

Students should be able to describe how, when substances change state (melt, freeze, boil, evaporate, condense or sublimate), mass is conserved.

Changes of state are physical changes which differ from chemical changes because the material recovers its original properties if the change is reversed.