Keith S. Taber
The term 'reaction' is used in at least two different technical senses in school science: in studying forces as one of the components of a interaction between two bodies such that they each experience a force ('action-reaction'), and as a chemical change which leads to a transformation of matter leading to a new substance(s).
Lomash was a participant in the Understanding Science project. Y7 student 'Lomash' reported that he had been heating materials in a Bunsen flame in his science lessons: "We were burning … coal and copper and things like that, metals."
When he heated copper "It went black…because the flame was too hot, and – it just went black , like paper." The copper stayed black after being removed form the flame, and this was because "it's something else, it's a reaction."
Lomash was using the term 'reaction' in the context of a chemical change – the copper had changed to 'something else', suggesting that he had acquired something of the technical meaning of the term as it is used in chemistry. However 'reaction' is used with a much more general meaning in everyday life, and on further questioning it seemed Lomash has not appreciated the special meaning given to the word in chemistry:
I: So what's a reaction?
L: It's like, a reaction is something that happens.
I: Okay, so if I fell off this stool, would that be a reaction?
L: Yeah.
I: And if you laughed at me falling off the stool, would that be a reaction?
L: Yeah.
I: Oh I see. So that's just another name for something that happens is it?
L: Yeah.
Where students already have meanings for words they come across in school science, they are unlikely to spontanously appreciate how the word is used in a specialised, nuanced way in this particular context. Perhaps Lomash's teacher had emphasised that in heating the copper 'something else' was produced, making the observed change a 'reaction'. Certainly Lomash happily accepted this was a reaction, but apparently only in his existing vague everyday sense of the term. His existing linguistic association for the term 'reaction' appeared to act as an associative learning impediment.
Read about learners' alternative conceptions
