Bert Suggests Chemical Bonding Evolved
Keith S. Taber
Bert was a participant in the Understanding Science Project. During one interview he reported that he had just completed a topic of alkanes and alkenes in his chemistry classes. He explained that a carbon atom has "to have four bonds", so if a carbon atom had "only got one two carbons on one side and one hydrogen then it'll make a double bond, to have four bonds". So I asked him what he understood a bond to be:
I: …what's a bond?
B: A bond is erm, it just, it's something to hold, hold two atoms together.
I: So what might you use to hold two atoms together?
B: Erm, So they can be kept, so that they're not too, I think it's just to make, so it can make big lines so it can erm, oh, so they, so not every, so because solids they have erm, I guess a lot of bonds, to keep it all, all together, I'm guessing. And erm like gas has a lot less bonds because it's a lot more free.
I: That makes sense [Bert], I'm just wondering what you would use to bond two atoms together. … I'm just wondering what kind of thing you use to bond two atoms together.
B: Erm • • I'm not sure. I guess, I guess they were just, when er, they're made with it I guess.
I: Yeah. Do you think it's made of adhesive? … is it made of a glue do you think?
B: No, I don't think so. I think it was like, I don't know, it could have been like evolution, like.
I: Ah.
B: Yeah, the atoms evolved so that they could hold on to each other.
I: Oh I love that. • • • The atoms evolved so that they could hold on to each other?
B: I guess so. That's how the world was made.
In this interview segment Bert seems not to have considered the nature of the bonds between atoms, but just to have accepted what he has learnt about valency. When asked about the nature of the bond he could offer no mechanism for bonding, but instead suggested that chemical bonds had evolved as "that's how the world was made". Here Bert is drawing upon a general explanation considered to be universal in the domain of living things, but applying his learning from biology to explain a physical phenomena.
This seems to be a creative association drawing upon prior learning, but the idea of evolution is being used outside is canonical range of application, leading to a potential associative learning impediment. Potentially, Bert's thinking about evolution as explaining how atoms can bond (a potential explanation about origins, though inappropriate if evolution is understood as natural selection) could stand in place of seeking a physical explanation for the nature of bonding.
