They are the beginning and the end, minuscule miracles that contain all the information needed to produce a sunflower, coconut, or great oak. They have sustained humans throughout history.
These amazing adaptations of evolution can lay dormant and withstand a host of environmental rigors until conditions suit them. They can be as large as coconuts or as fine and ephemeral as dust. Some are bare and others surrounded by fruit. They can be hairy, smooth, ridged, winged, or tufted. In school, they can capture imaginations and spark science investigations far beyond the bean in the paper cup. Read on to learn how seeds can intrigue and inspire your classroom gardeners and scientists.
"My middle school students had been fascinated by the incredible diversity of textures, colors, and patterns revealed when they explored seemingly dull seeds under magnifiers," reports Seattle, WA, teacher Sarah Carlson.
"After looking at seeds from nasturtiums, daisies, morning glories, and other plants we had grown or discovered, we decided to do a more in-depth study with sunflower seeds -- the favorites of our classroom birds."
With an eye toward exploring the relationship between form and function, Sarah's students used an approach to observing and thinking by analogy detailed in materials from The Private Eye Project. Each student began by drawing a circular frame using a petri dish as a template, then chose a sunflower seed to inspect. Using "jeweler's loupe" magnifiers, students then got up close and personal with their seeds. "The simple jeweler's loupe is better than a hand lens because it cuts out other distractions so kids can more fully explore previously unseen worlds," explains Sarah. "I started by reviewing some drawing techniques with the kids, such as drawing the seed larger-than-life, trying to fill the frame, and focusing on basic shapes and patterns of light and dark," she adds.
As students observed their seeds at five and ten times magnification, Sarah had them identify at least five things their seeds reminded them of or looked like, then write down the analogies: The sunflower seed reminds me of a zebra ... a tree branch ... a butterfly cocoon. Next, students asked, Why does it remind me of that? "We followed up by discussing whether we can create theories about the function of what we observe based on what it reminds us of," explains Sarah. "That is, if it reminds us of something, it might function in a similar way," she adds. For instance, If a seed coat resembles a shield, might it in any way act like a shield for the seed inside? If it resembles a cocoon, how might it help the seed if it also acts like a cocoon? The class discussed how they might test their theories or hypotheses, for instance, by trying to "damage" seed coats (by freezing, burning, pounding, and so on), then seeing if seeds would still sprout.
To prepare to explore the mystery of seed germination, students sandwiched seeds between paper towels in petri dishes, then moistened them with a sprayer. They stored the dishes out of the sun and daily opened them to let in air. "As the tiny roots and shoots emerged in only three days, students were delighted to see what had seemed 'dead' spring to life," says Sarah. Again, students were inspired to look closely and think in analogies: The roots remind me of blood vessels or a map because the roots are like roads going off from the main road. "These descriptions provided fertile ground for more discussions about how the structures of many living and nonliving things have similarities that reflect their functions," she explains.
As a culminating activity, students created accordion-shaped books that featured their artistic depictions of seedling stages along with their edited analogies and descriptions of what their vigilant inspection revealed. "These and other up-close seed and plant part investigations really helped students see the connections between the form and function of living things, appreciate their diversity and similarities, and develop a more intimate view of nature," notes Sarah. "What's more, as they honed their observational skills and ability to focus, they produced some simply amazing art!" she adds.