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Simple Stem Experiment for Grades K-3
Materials: Two or three medium sized celery stalks—preferably with leaves; glass or jar, blue food color, water Easy Instructions: Cut the bases off your celery stalks. Stand them in a glass or jar filled with two or three inches of water, colored a dark, bright blue with ordinary food color. Suggestion: Add some small, clean stones to the bottom of your glass for ballast. Blue food color works better than the traditional red. Before you prepare your experiment, ASK students if they can describe how plants move water from roots to leaves. BRAINSTORM some answers. ASK how you might go about discovering an answer to the question. Students may come up with the food color experiment by themselves or with some gentle guidance from you. Prepare the experiment so that students can see what you're doing. ASK what is likely to happen. Let students GUESS or PREDICT as many different possibilities as they can. After 24 hours, remove one stalk from the glass of blue water and cut it an inch or two above its base. You should see blue dots, which are cross sections of xylem (zi´lum), the "pipelines" that transport water through trunks, stems, and twigs to leaves and flowers. You'll also see tiny veins in the celery leaves, clearly marked by the food color. What would happen if you put a white flower in a glass of blue water? Or—for St. Patrick's Day—in a glass of green water! Older students may be interested to know that xylem consist of strings of long cells, tubes, and woody fibers that pass water through permeable cell walls. Complementary phloem (flow´um) move nutrients (sugars) manufactured in leaves down through the plant to stems, trunks, and roots. |
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