Kinetic theory of matter
Explaining the behaviour of matter using the idea of particles is a powerful and accurate theory however it is known to cause some conceptual challenges for some students. Being able to describe macroscopic behaviours in terms of a microscopic model that cannot be seen and moving between these two domains is not intuitive. You may wish to use the terms macro and micro and signpost which world you are in when teaching this subject until these ideas become established in the students’ minds and ways of working.
They need to know that kinetic theory of matter assumes all matter is made of small particles which are in random motion. By making simple assumptions about these particles a lot about the physical properties of matter and how it behaves can be explained. They need to identify three main phases of matter, solid, liquid and gas as well as to differentiate them by the different behaviours of the particles in each phase.
Gases are particularly well modelled this way and the behaviour of the particles allows us to deduce empirical relationships between the pressure, volume and temperature of the gas and to make testable predictions.
Similarly the meaning of density can be discussed for all three phases using kinetic theory, as well as to be able to consider the pressure exerted by a fluid such as water due to the height or depth of the fluid. Applying the formulae relating the quantities of mass, volume, density, pressure, depth of fluid and gravitational field strength; exploring how changes in these are inter-related revisits math skills.
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.