"During a unit on herbs last fall, my high school students became interested in collecting plants around the school, then making herbarium samples (see below) and using books and online resources to research what they'd found," reports Roxbury, MA, teacher Gabrielle deBear Paye.
As students began to realize the range of ways herbs were used throughout history, they started interviewing family members about how different plants were used in their own cultures. From this, ideas emerged for "testing" traditional lore, and a range of plant-based science fair projects were born. "I make it very clear that students could only use plants sold in food stores as herbs, teas, and so on, and that they had to clear choices with me," notes Gabrielle.
One student who learned that chamomile tea is used to promote sleep wondered if it would help her younger sister fall asleep faster. The student set up an experiment in which she gave her sister either chamomile or a placebo tea each night, then counted the minutes until she dropped off.
Another student heard from a parent that raspberry leaves can help ease menstrual cramps. Female teachers and students were recruited to participate in her investigation, with sufferers receiving either raspberry tea or a placebo of plain tea. The student devised a questionnaire asking 20 subjects to rate from one to ten the amount of relief they felt, then tallied results. "Students reviewed their experiments and findings, in some cases deciding to use bigger sample sizes or to do further research," reports Gabrielle. "Although by no means conclusive, these investigations engaged the kids in making cultural links, testing claims like scientists do, and appreciating the impact of plants on our lives," she continues.
If your students are growing or gathering herbs, they may want to press and save herbarium samples, much like botanists do in the field. They can then use the pressed specimens to create a field guide, illustrate a cookbook, send to other classrooms, or reference in their science journals.
To preserve samples of leaves and other plant parts (roots, stems, or flowers), you'll need cardboard squares, paper towel or newsprint, and your plant specimen. Place a cardboard square on a table, followed by a square of paper towel or newsprint, a leaf or other plant part, another piece of absorbant towel or newsprint, and finally another cardboard square.
Continue adding to this stack in the same order until you've pressed all your plant material. Put a rubber band tightly around the stack or place a heavy object on the pile. In a week or so, carefully remove your pressed plant parts, put each on a white paper square, and peel and place a piece of clear contact paper over the specimen.