Asking questions about test tubes
November is a busy time for ASE events. These are great networking opportunities and a good way of finding out about current developments and great ideas for teaching. At the West of England event I shared some ideas about GCSE questions on the new specifications relating to practical investigations and this seemed to generate some interest.
My starting point was the sample assessment materials from the exam boards. These include questions based on stipulated practicals. What is interesting to explore is the extent to which these questions assess recall of specific procedures. In other words, if students have learned those experiments well, does that give them access to the available marks?
Well, it depends. One of the questions I used was on investigating factors affecting the rate of photosynthesis. If you’d done the experiment and understood the design, you’d be OK. Another was on reaction times, but then asked how the (flawed) procedure could be improved (stating one improvement would get you a maximum of two out of the six marks available). Then there was an interesting one on enzymes which asked how the action of chymosin could be investigated. This particular enzyme isn’t mentioned in the specification but, of course, the idea is that if students understand enzyme action they can apply it to this. Another question was about analysing a graph showing results from four different groups of students who had investigated the loading of elastic bands. Candidates were asked to suggest reasons for variation in the results, sources of error and ways in which a particular group could extend their investigation to show plastic deformation.
The point from this is, of course, that ‘learning the protocols’ won’t be enough. One of the boards has included in their spec a list of question stems that could be used as a basis for questions around the stipulated practicals. The next step in the workshop was for participants to suggest which of these skills could be best explored in which expected investigation. Some contexts are better ways of exploring, say, management of safety and others work well regarding the management of variables.
Although this makes the teaching of lessons more challenging it ultimately saves the stipulated practicals from becoming another artificial procedure (“sorry guys, you’ve just got to memorise this list of experiments – yes, I know you’ll forget them straight after the exam but try and hold on to them until then”).
Now, there’s a sizeable health warning to be attached here. The draft specifications and sample assessment materials have all been rejected. However, this doesn’t alter either the requirement for there to be questions based on these experiments or for these questions to be split between knowledge & understanding, application and interpretation & evaluation.
It’s worth having a look at the sample questions and it’s worth thinking about how to prepare students effectively. It’s also worth seeing if you can get to an ASE event; the annual conference is at Birmingham University from January 7th to 9th. I defy anyone to come to an event like this and not come away with anything of value.