Yesterday, my elementary class made a model starch molecule as part of their unit on food chemistry.
The model starch molecule is the pink construction paper chain that you see the children holding here. The children loved creating this model molecule – they were thrilled by the idea that starch could simultaneously be a large molecule and be completely microscopic. The cutting, taping, and stapling was pretty fun, too.
From a pedagogical point of view, I am somewhat dubious about the value of introducing specific information about atoms and molecules at the elementary level. There is a very good argument to be made that molecules are too abstract to be developmentally appropriate for this age. On the other hand, the kids have all heard about atoms and molecules and they bring the words up in conversation, so it seems reasonable to provide them with a simple model that is more accurate than what many of them are currently imagining.
As this unit continues, we will build a model of a protein (that will be a long, multi-colored chain, with the different colors representing different amino acids), a model of glucose (a single pink link, identical to the ones in the starch chain in the photo), a model of a fat (three long paper chains linked together at one end). If we’re feeling ambitious, we might make a fiber molecule… or we might not, since it would have to be much bigger than the starch molecule.
At the end of our study of food chemistry, I’ll be doing some assessments to find out how what the children have learned about the molecular structure of food molecules and how they conceptualize molecules. I’m very interested in the results – I wish I had more classes so I could do some controlled experiments to throw light on the effect of different approaches to teaching this topic.