"By fourth grade, it seems that students' creativity and curiosity are often squelched," reports Easton, ME, teacher Vaughn Martin. "To counter that shift, I always seek ways to spark their interest and bring learning to life," he adds.
Vaughn keeps his GrowLab plant investigations student-centered and involving by challenging students to figure out how to grow and maintain different plants, rather than giving them all the details up front. For instance, after his students observe plants indoors and out, Vaughn challenges them to figure out how people grow different types of plants. When a student says, "I've seen my mother grow houseplant cuttings in water," for instance, the class brainstorms a variety of other approaches, then small groups experiment to test different strategies. Each student keeps a log of the study, then creates graphs to help organize the data. "It takes a while for fourth graders to understand the idea of variables and controls, so we apply the concept early on to our group experiments, so students can use it on their own later in the year," says Vaughn.
Before studying soils and other growing media, Vaughn invites pairs of students to bring in 12 different media they think they can use to germinate seeds, then challenges them to test their ideas using egg cartons as germinating chambers. "Students found, for instance, that cotton balls work great, but that a paste made from flour didn't, which prompted a discussion about the qualities of a good germinating media," says Vaughn. They then examined synthetic soilless mix and compared it with outdoor soil. "Once the students have tried to find their own answers -- such as which growing medium works best -- we visit a real greenhouse to learn how 'experts' do it," says Vaughn.