Scientific theories are constructs (models) that we use to explain our observations. They are different from scientific laws, which are rules that have to be obeyed and which can be applied across a wide variety of situations. The best known example is the Big Bang Theory but we'll be looking at a theory that relates … Continue reading Kinetic Theory
Thawing a frozen balloon
The pressure, volume and temperature of a gas are all linked so it makes sense to keep one of them constant when investigating the interdependence of the other two. But we didn't do that when we watched the effect of liquid nitrogen on a partially-inflated balloon - as shown in the animation below. Before viewing … Continue reading Thawing a frozen balloon
Phase-change diagrams
The concepts of specific heat capacity and specific latent heat are nicely illustrated in phase-change diagrams. But how realistic are the diagrams that are commonly seen online? The answer, perhaps surprisingly, is "not very". The phase-change diagram shown below is useful in terms of the amount of information it provides but, in common with many … Continue reading Phase-change diagrams
Absolute Zero
Where does the idea of "absolute zero" come from? In part it stems from a need to avoid negative temperatures but a better explanation can be found by thinking about the kinetic theory of gases. When a gas is heated, its particles gain kinetic energy. This in turn means that the particles have a higher … Continue reading Absolute Zero
Under(water) Pressure
Pressure explains why an applied force makes a drawing pin goes into the noticeboard and not your thumb: it also explains why a sharp knife is safer than a blunt one when practising culinary skills. There is also another aspect of pressure that relates to forces within a fluid (liquid or gas) and that is … Continue reading Under(water) Pressure
Specific Heat Capacity
Heating a substance can cause either an increase in temperature or a change of state. This is not completely obvious, so let me put it another way; sometimes when we "heat up" a substance it doesn't actually get any hotter. The reason for this is that the energy supplied is being used to break bonds … Continue reading Specific Heat Capacity
SP8-9 Forces Doing Work (mini-test)
The first module of Y11 is now complete and to help you prepare for the assessment I have created a mini-test, complete with mark scheme and explanation. You can access the test by clicking here and the mark scheme is here. Work through the questions then check your answers to spot any errors or misconceptions … Continue reading SP8-9 Forces Doing Work (mini-test)
All about Springs
The facts and understanding that you need to have about springs is less detailed than it is for some other GCSE Physics courses. It is therefore important to use learning resources that are matched to this particular course. If you start reading about ultimate tensile stress, for example, then you are learning too much! The … Continue reading All about Springs
Mr Tarrant's physbang 'blog 