Autumn is here! Fall's colors provide the perfect motivation for teaching about photosynthesis across the grades.
Included: We've raked up a pile of activities for you to "leaf" through!
It's fall! That means shorter days and cooler nights. And, in many parts
of the United States, it means that trees will soon shed their leaves
after a final colorful salute to summer.
Trees that drop their leaves each fall are called deciduous
trees. You might ask your students why they think dentists refer to baby
teeth as "deciduous teeth"? See if your students can figure out the connection!
And here's another question for your students: Did you know that a tree's
leaves are orange and yellow -- even in summer? Most leaves include the
pigments of all three colors. It's just that the pigment chlorophyll (the
pigment that makes the leaves green) is a much stronger pigment than the
others. It covers the yellow (xanthophyll) and orange (carotene) pigments
that are natural to a tree's leaves. But, come fall, a tree's leaves produce
less chlorophyll. Now the other colors can show through. And that they
do -- in brilliant explosions of color!
Another pigment (anthocyanin), which produces reds and purples,
isn't present all year long in most green leaves. It only shows up as
the nights get cooler.
Fall is a great time of year for teaching about the process that gives
life to trees. This process is called photosynthesis, which translated
means "putting together with light." As winter nears, less sunlight and
less water -- elements essential to the process of photosynthesis -- will
be available to trees. That means less food for deciduous trees! Soon
the tree's photosynthesis (food-making) "factory" will shut down and the
tree will rest until spring when water and light again awaken the process.
On the Web, you'll find a wide variety of sites for teaching about the
arrival of fall's colors. The Internet is full of valuable resources for
you and your students. Some sites are scientific in their orientation
-- and others are just full of pretty pictures.
If it's pretty pictures you're looking for, check out New
England Foliage. Here you'll find all kinds of clickable pictures.
(Just click on the picture to see a larger, full-screen version of the
image.) Check out the fall colors all across the United States at the
Fall
Foliage on the Web site. See colorful images from the eastern U.S.
as well as from California, Michigan, Wisconsin, and more.
If it's a simple explanation of why some trees' leaves turn color each
fall, check out Why
Leaves Change Color from the College of Environmental Science and
Forestry of the State University of New York. For a more detailed explanation
(including an "I Can Read" version written just for young students), and
for a handful of hands-on science activities that teach about fall's colors,
see Simply Science's Why
Do Leaves Change Color in the Fall? One really cool experiment at
this site involves the use of rubbing alcohol, so it might be appropriate
only for older students. Also, check out the Fun Fact question (What
do autumn leaves and ripening bananas have in common?), which will
help teachers of all grades to teach an important leaf-color concept.
Looking for simple explanations and activities? Newton's Apple, the
PBS science series for kids, offers Photosynthesis.
The site includes a discussion of the process, vocabulary, resources,
and activities.
Check out a simple
lesson plan from ERIC. The lesson's objectives include observing the
effect of light on plants and understanding how green plants use the sun's
energy to produce food through photosynthesis.
The U.S. Forest Service provides a bunch of links to fall foliage sites.
If you're interested, check out the Follow
Fall Colors by Telephone page.
And, for more advanced information about synthesis there are a ton of
sites. Check out the ASU
Photosynthesis Center. From Arizona State University, the site includes
links to many other sites.
Read aloud. Top Secret by John Reynolds Gardiner (author
of Stone Fox) is a great read-aloud book for the elementary/middle
school grades. Written at about a fourth grade level, the book tells the
story of a boy who decides to solve the mystery of photosynthesis for
a school science project. Students learn all about photosynthesis from
the book.
Science/study skills. Collect a variety of leaves and challenge
students to use a tree guide from the library to identify the kind of
tree from which each leaf comes. To protect the leaves, you might laminate
them. You might even join a listserv and post a message asking teachers
in other regions to join in a leaf exchange. You're bound to meet up with
a teacher willing to share native leaves.
Preserving leaves. Collect samples of colorful leaves and place
the leaves between sheets of wax paper. Set the iron to a hot setting.
Cover the layers of wax paper with a couple sheets of newspaper and iron
them.
Hands-on science. Students can observe the effects of light on
the color of leaves. When leaves on a tree are still green, invite each
student to cover part of a leaf with aluminum foil. (Choose a tree that
you know will turn bright colors.) Use masking tape to tape the foil to
the leaf. Students can sign their name on the masking tape. Wait until
the leaves on the tree change color. Then remove the foil and see the
colors that were in the leaf all summer!
Graphing. Let students work in teams to take a census of the
trees in your school yard, an area of a nearby park, or another defined
area. Students can use the survey data to create bar graphs that show
the numbers of trees of different species.
Spelling. Invite students to unscramble some fall-related words.
Spelling counts! Choose appropriate words for your grade level. Possible
words: llaf, veales, pinkump, rogane, Sbermpete, tamuun, tempgin, phlorlochyl,
lowley (fall, leaves, pumpkin, orange, September, autumn, pigment,
chlorophyll, yellow)
Art. Leaf rubbing is a fun art project. Students first place
a leaf flat on the table. Then place a sheet of tracing paper over the
leaf. Use a soft pencil or a crayon and gently rub over the tracing paper
until the outline of the leaf shows through. Add additional leaves and
use different colors for a nice effect.
Article by Gary Hopkins
Education World® Editor-in-Chief
Copyright © 2005 Education World
- How and Why the Leaves Fall: A Story Sketch by Bert Horwood
and Bob Henderson, Pathways: The Ontario Journal of Outdoor Education,
July-August 1995. A short story compares an old man's tale of why the
woodland animals prepare for winter and why the leaves change colors
with a teacher's science-based explanations. Commentary distinguishes
inquiry of wonder (why) and inquiry of power (how), and suggests ways
to record the story for oral retelling and adapt it for use with young,
older, and university audiences.
- Hands-On Whole Science: A Leaf Sampler by Lynne Kepler, Instructor,
October 1991. Two activities to help elementary students learn about
autumn. The activities use autumn leaves to teach that each type of
tree has its own distinctive type of leaf. One activity involves tracing,
drawing, and writing about leaves; the other involves making a quilt
using leaf designs.
- Fall for Science, Learning, October 1992. Presents a
collection of inexpensive autumn science activities for elementary students.
A full moon activity encourages observational and critical thinking
skills. A pumpkin activity teaches physics. A spider activity teaches
biology and alleviates unnecessary fears. A student page has children
create a bookmark that shows faces in the full moon.
* Source: ERIC
Links Last Updated 09/12/2007
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