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Each year as we begin our discussion of energy transfer in biological systems, my Middle School students tell me that plants need food. For many years, I have discussed with them the title of plant food given to the boxes of fertilizer they see in the supermarket. I ask them to describe what food means to them; they list corn chips, salad, pizza, tacos, hummus, and other foods they eat. For an assighment, I ask them to keep a three day diary of all the food from plants that they eat and list the part of the plant from which it comes, root, stem, leaf, flower, or seed. At the end of the three days, the students are surprised at how much they depend on plants for food. Then we discuss how plants become food using the story of photosynthesis. Students tell one another the story, they manipulate papaer atoms to play out the chemical process and then use ball and stick chemical models to reinforce the process.  They engage in many experiments to support the story. Still, at the end of the year, an occasional student will announce during class discussion that plants need food.

Paul suggested that the story, plants need food, may be a one from the unconscious brain. His observation started me thinking that the story of absorbing nutrients is a powerful one for survival. The villi in the small intestine are responsible to absorb the digested nutrients we use for building blocks for growth, replacement, and repair. These nutrients yield energy stored in their chemical bonds for cellular work. The unconscious brain directs the search, ingestion, digestion, absorption, and distribution of new matter to the cells of our body. If humans need food, why shouldn't other living things? Paul's comment offered me valuable input to rethink how I will initiate the conversation of energy transfer in biologically systems. I will start out with the same approach and engage the students in conversation, experimention, and reflection. This year I will ask the students more pointedly to explain from what source the matter comes for the sugar molecules produced as a result of the photosynthetic process. I thought manipulating the ball and stick models was enough for them to understand that the carbon for the sugar comes from carbon dioxide, but I understand that to revise the story in their unconscious, some students will have to also verbalize the connection. Perhaps, I will assign them to write a story about how sugar is made by plant and also ask how plants obtain the other matter needed to make other compunds such as proteins. In this way, I will not be inhibiting them from drawing on the knowledge and experience of thier unconscious brains. Of course, this will take time, so some other less interesting topic will be abandoned for the moment.

Note: This is my third Institute, and as I become a better teacher, I find that I teach less content and teach more an approach to learning.