- molecular kinetic theory
- ideal gases; pV = NkT
- absolute zero
- relationship between temperature and average molecular kinetic energy
- internal energy
- energy required for temperature change = mcΔθ
For most classes, the equation linking a thermal store of energy to the temperature change is a good place to start. This will be familiar from their GCSE specification, if for no other reason than the fact it is one of the only equations they cannot rearrange using the 'triangle method'. Although not required, comparing this with the equations for latent heat reminds students of the fact that heat supplied can cause two kinds of change in a substance. This then allows you to gauge their understanding off the subtleties of molecular arrangements in various states of matter. Those who study chemistry will probably have a lot to offer in discussions here.
The size of your class will determine how many of the practicals can be done by students, perhaps in a circus, and which you demonstrate yourself. This is a great opportunity for data analysis and best fit lines which do not go through the origin - until the numbers lead to the concept of an actual, meaningful or 'absolute' zero. The individual relationships - each of which can be predicted by discussion and thought experiment - can be combined to give the ideal gas equation. At this point many pupils will appreciate some practice with problems requiring them to simplify from this to a straightforward relationship before solving numerically (different specifications may require different levels of recall for the derivation).
Past exam specifications and questions have often asked students to be clear about the assumptions and limitations of the ideal gas model. In fact, students are often surprised by just how good the results of the equations are when they realize what we must ignore.
The expressions for internal energy and how this relates to particles can be challenging for many students to visualise. In particular it is worth spending a little time on the relevance of the 'root mean square' speed. Those students studying a statistics module in maths can often make good suggestions for this.
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 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.