With the cornucopia of smells coming from the kitchen, the cool breezes, and the sound of crisp fall leaves under foot, fall has always been my favorite time of the year. Perhaps because we have relocated and the ecology is so different from the coast (where I grew up), the Willamette Valley (where I attended University), and Central Oregon (where I began my adult life) … the current nature challenges at Handbook of Nature Study have inspired me more than ever.
We have avidly been exploring the area and journaling about our observations and discoveries. Lessons on leaves have been sprinkled throughout our outings and we’ve enjoyed looking for and getting to know the plants whose range does not extend into Oregon (at least not naturally).
After collecting and pressing a number of autumn leaves, we sat down together with a dichtomous key and walked through it to identify the numerous samples of leaves that we had collected.
A dichotomous key is a method for determining the identity of something (like the name of a a plant, an insect, or a rock) by going through a series of choices that leads the user to the correct name of the item. Dichotomous means “divided in two parts”. At each step of the process of using the key, the user is given two choices; each alternative leads to another question until the item is identified.
For example, a question in a dichotomous key for trees might be something like, “Are the leaves flat or needle-like?” If the answer was “needle-like,” then the next question might be something like, “Are the needles in a bunch or are they spread along the branch?” Eventually, when enough questions have been answered, the identity of the tree is revealed.
Many of the leaves we had collected we already knew, but it was a good opportunity to review vocabulary and focus on some of the smaller details or distinguishing characteristics of leaves.
Another day, I provided each of the kids with a page of clip art leaves and asked that they use chalk pastels to show the colors of fall. They didn’t show much color value so we opted to do this a second time using water colors.
An expanded version of this lesson is available in the Science Logic curriculum
Life Logic: Plenty O’Plants.