Beyond ‘human error’… What would happen if…?

Blog post as part of #ASEslowchat

So we are in ‘new’ GCSE land…. I am lucky, I have already been in this land for a while, 5 years in fact. At my school we have been teaching the AQA iGCSE L1/2 certificate chemistry, a linear GCSE with no ‘coursework’ e.g., controlled assessment/ISA etc. This specification has now been cancelled, I suspect because the new ‘home’ AQA GCSE is so similar to it.

In this post for #ASEslowchat I want to discuss approaches for helping pupils to answer the practically focused questions in the examination. One key feature of the iGCSE was the paper 2 which was made up of mostly practically focused questions. A recurring question across a number of topics is –

  • ‘what caused the anomalous result?’
  • ‘why did the pupils get a lower result than expected?’

The first line of defence for pupils when faced with these questions is ‘human error’. This is always insuffient and pupils need to be encouraged to think of other reasons. This can be really difficult for them.

Because of this I have introduced carefully designed questions to go alongside practical work, starting as early as Year 8. Pupils are presented with things that could possibly have happened during the experiment and are asked to consider what the effect on the result would be. In the example below we were in the topic of metals and non metals and one of our big focuses of the year has been the law of conservation of mass.

Section of a worksheet used wth Y8 pupils to expose them to different lab scenarios and get them to think about the consequences.

The ‘tick box’ nature of the question makes it accessible for younger age groups and I then get them to explain it when we are going through the answers so I can hear their reasoning. This is then followed up in their assessments where they will be asked to give a written answer and explanation. So far, results are encouraging, it seems to be helping boys to think more deeply about their practical work and how results can be influenced by the action of the experimenter or the apparatus.


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