In a sea of green vegetation, you’ll find reds, yellows, oranges, blues, and purples—a beautiful range of colors that pop out, saying to insects and other pollinators, “visit me, visit me, no, not that one…. me!” Flower colors have evolved to attract certain kinds of insects and birds, which ensures they can propagate the next generation of pinks, daisies, and other vegetative offspring.
How do they do it? With such pigments as porphyrins, carotenoids, anthocyanins and betalains. In addition to making flowers attractive to specific pollinators, these compounds also help plants sustain photosynthesis by gathering wavelengths of light not readily absorbed by chlorophyll.
We have reached the 14th week of the weekly, online, video series “Chemistry Now,” and chemistry returns to nature as a source of interesting video and lessons. As we’ve written before, please view the video, try the lessons, and let us know what you think.
Photo: T. Brown
Through the Chemistry Now series, NSTA and NBC Learn have teamed up with the National Science Foundation (NSF) to create lessons related to common, physical objects in our world and the changes they undergo every day. The series also looks at the lives and work of scientists on the frontiers of 21st century chemistry.
Video: Roses are red; violets are…well, violet – but why? “The Chemistry of Flower Color” explains how pigment molecules – carotenoids and anthocyanins – give flowers the colors we see. Also in this collection: news stories from the archives of NBC News and Scientific American on desert wild flowers, pollination, the cut-flower industry, and why flowers have scents.
Middle school lesson: In What Color Is Your Flower? (middle school), students separate the pigments in red flower petals and determine if all red flowers contain the same pigments.
High school lesson: Students go a step further in What Color Is Your Flower? (high school) and determine which of the pigments they separate out exhibit acid–base indicator properties.
For another great pollination activity, see “Please Pass the Pollen,” through which your students learn the sorts of pollinators that visit plants around your school and which flowers are most often visited, and then they return to the classroom and report their findings.
You can use the following form to e-mail us edited versions of the lesson plans:
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