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Sprout & Measure Seedlings for Grades K-4
Materials: Zip lock sandwich bags, paper towels, seeds (raw sunflower seeds, popcorn, black eyed peas, beans—from the grocery store), scissors, tape, labels (optional); rulers Easy Instructions: Cut a paper towel in half, fold it to fit your sandwich bag, soak it with water, and place in bag. Add about six sunflower seeds, popcorn, alfalfa seeds—or peas or beans that have been soaked overnight. Close bags securely. Label with kind of seed and date. Tape to the inside of a sunny window or in cold climates in a warm place where bags can get some sunlight. Start a class discussion by asking the same kinds of questions you asked in activities 1 and 2. Be sure to check your seeds two or three times a day. What are they doing? How are they changing? Peas and beans sprout most quickly—followed by sunflowers, and popcorn. How fast will your sprouts grow? How big will they get? The first leaves to appear from a sprouting seed are called the cotyledons (kot´l ēd´n). Help students learn to pronounce this "scientific term" and ask them to let you know when they see the first cotyledons appear. Use a magnifying glass to get a good look at what emerges from your seeds. COUNT the seeds that sprout and those that don't. Figure our your sprouting "success rate" by figuring the percentage of seeds that sprout. Use standard or metric rulers to MEASURE sprout length day by day (with plenty of light and warmth, sprouts will grow quickly enough to measure more than once a day). Figure out rate of growth by adding the amounts sprouts have grown and dividing by the number of days you observed them. COMPARE your seeds to the narcissus bulb. What is the same? What is different. If you sprouted different kinds of seeds, how were they the same? How were they different? ASK MORE QUESTIONS: Do your sprouts need light? How do seeds germinate underground? Do sprouts need water? How do sprouts germinate in the desert? Where does the embryo—the tiny baby plant—come from; is it inside the seed? CREATE EXPERIMENTS to answer your questions. Ask students to think of ways to answer questions through observation. Try growing some sprouts in the dark—or in a cold place. Do your seeds germinate? Are the sprouts different from those you grew in sunlight? Cut open a bean or a peanut that you've soaked overnight and put in the sun for a day (one that hasn't sprouted). Can you see a tiny plant inside? (HINT: in a large, soft seed ready to sprout, you can usually spot the embryo—a tiny root-stem and two cotelydon. Use a magnifying glass to look for the teensy cotyledons.) BRAINSTORM together to think of more questions and experiments. Can you find some seeds outdoors? What can you do with these? What would happen if you planted your sprouts in a pot of dirt? Bring in lots more seeds from your kitchen (peas, lentils, all kinds of beans, dill seed, anise seed, fennel, pumpkin, squash, melon, apple, orange, grapefruit, tomato, chili, raw nuts). Cut some of them open. Can you find the teensy, tiny baby plants inside? Use a magnifying glass to explore seeds. If you're growing a narcissus, ASK students if they think the plant embryo was contained in the bulb. Is a bulb a seed? (HINT: A bulb is a short, basal stem covered by leaf scales. A healthy bulb contains the entire adult plant in embryo form—flowers and all.) |
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