Many years ago I had the opportunity to help pilot test a new biology lab curriculum for nonmajors. It is through this experience that I came to see the many ways people learn. It is also how I came to appreciate the Herculean effort required to design, write, implement, evaluate and fine-tune a curriculum. I think of this experience often, especially when I read about activities such as the leaf-building activity that is the focus of this week’s column.
We’ve learned how describing a concept with words and how visualizing words can make invisible processes easier to understand.
Today we go 3-D and consider model-making. The leaf-building exercise we’re going to learn about was created by science teacher Patty Littlejohn. She describes the model-building process and how she uses the models to enhance student understanding of photosynthesis in Building Leaves and an Understanding of Photosynthesis.
Littlejohn (2007) makes photosynthesis easier to think about by making the process of photosynthesis larger than life.
To help her middle school students see, feel and experience photosynthesis, she has them build a model of a leaf, a plant cell and an animal cell. Students build leaves with veins, chloroplasts, stomata and an epidermis. Their plant and animal cells have cell membranes and organelles. Littlejohn says students benefit from the model-building exercise because it requires them to “see and manipulate the reactants and products of photosynthesis and cellular respiration” (Littlejohn, 2007).
In addition to their leaf and cell models, students also create reactants and products (i.e., carbon dioxide, oxygen, water, energy, glucose) and combine reactants to simulate the chemical reactions occurring within plant and animal cells. By engaging students in the construction of both cell types, Littlejohn (2007) is able to show students how energy is transferred between organisms.
Littlejohn (2007) includes detailed instructions and material lists in her article so that teachers can bring this same experience to their classroom or program. Littlejohn’s article can be purchased online for 99¢. You can also look for her article at your local college library.
Littlejohn, Patty. 2007. Building leaves and an understanding of photosynthesis. Science Scope. 8(30): 22-25