One of our science technicians told a story a few days ago about her youngest child. He is one of the first years at school (I’ve just realised as I type this I’m not really sure how it works in the mysterious, swirling mist-drenched realms of early Primary school; is it reception years, or do they start at Year 1?) and they had apparently been studying castles. Mum was asking him various mum questions about castles and so on, and he said that he thought castles would have been very warm places. She pushed further (what a wonderful example of pushing questions to assess knowledge etc. etc.) to find out why he thought this.
‘Because they didn’t have radiators’ was the answer.
At some point, the teacher had made the entirely true statement about castles, ancient ones at least. In his head however, the reason castles did not have radiators was because they didn’t need them, not because they weren’t invented yet. This is a great example of a child’s thinking – when there is missing information (in this case a chronology of plumbing and associated central heating systems) the brain will start to fill in reasons based on what it does know. This also neatly shows one of the great dangers of teaching science (not to life and limb, although that does sometimes occur). I’m talking about what we don’t teach because we assume it is already understood. These are the known unknowns. We understand that our students have holes in their knowledge, but we are not so good and identifying those gaps.
Ah, this is when good questioning techniques become so valuable calls out somebody from the back of the room nodding with recognition, a slight smile curving up on one side of their mouth. Well, yes and no. No denying it is important to know what the students really know, but there is a problem of how deep down the rabbit hole you are prepared to go. An example that grinds my gears is one used to explain circuits using the model of a central heating system (see, how that tied together?). So I can explain the flow of an electric current by explaining how it is like water flowing through the pipes and radiators, and a pump is like a battery providing energy to move the current. But unpacking this explanation shows that a student would need to know what a central heating system is, that there is water in it, what a pump does, why the water needs to be moved around anyway, possibly what the boiler is doing and what a boiler is and so on and on…
Each of these statements requires more and more unpacking, an explanation Inception. What the other 29 students are doing while you draw detailed blueprints of the geothermal network keeping Winterfell warm throughout the never ending winters is anyone’s guess. At some point you have move on with things and try the best you can to take the students with you. There are going to be some gaps in student’s knowledge, and they will build their own misconceptions around them. You will probably not be aware of them unless they turn up in a test answer. It’s often surprising to find out how much students know when they come to secondary school, but it is also surprising to find out what they don’t know that you would assume is either obvious or must have been covered. Nor is the knowledge evenly distributed across a class. The best defence may be to know what the main misconceptions are and be on the lookout for them, being careful of the examples and models you use, and things that the students are familiar with. It’s an endless source of frustration to me that I can’t use examples from popular culture to explain and model things in my classes because my cultural touchstones* (Star Wars for example. Well, let’s be honest, that’s pretty much all you need) are no longer the same as those of the students. Though of course, it’s the students who are wrong in such matters.
*I do still use this when teaching purine-pyrimidine bonds A=T is a double bond, in other words an even number like the AT AT walkers. I also explain that TUC are pyrimidines by remembering that Tuc biscuits come in a yellow wrapper which looks a bit like desert sands and hence ‘pyramids’. Yeah, I do.