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|In Living Color: Fall Leaves|
Fall is the season when the leaves change colors from green to shades bright red, orange and yellow. This unit's lessons will take you on a "leafy" exploration of this colorful time of year!
As the summer days grow shorter and cooler, we prepare for fall, the common name for autumn season. Fall begins at the autumnal equinox, the time when the sun crosses the equator. In the Northern Hemisphere, north of the equator, fall usually begins on September 22 or 23 and lasts until mid December. In the Southern Hemisphere, south of the equator, autumn lasts from March until early June.
Why Leaves Change Colors
In addition to green pigment from chlorophyll, leaves also contain yellow pigments from xanthophyll and orange pigments from carotene, the same chemicals that give colors to foods such as bananas and carrots. For much of the year, those colors are hidden by the large amounts of green pigment in leaves. In fall, fewer hours of sunlight and cooler temperatures cause leaves to gradually stop making food, the green color disappears and the yellow and orange hues become visible.
During the fall, other chemical changes cause the formation of red and purple colors in leaves from anthocyanin pigments. These pigments are common in flowers and foods such as apples and grapes. The amount of pigment mixture determines the range of colors in the leaves.
Weather conditions -- amount of sunlight, temperature, and water -- play a significant factor in the intensity and length of fall colors. The vivid red colors need warm, sunny days and cool nights above freezing. Trees that are protected by shade are often yellow. An early frost and too little rain will reduce the depth of the colors.
Do All Trees Lose Their Leaves in Fall?
Deciduous trees, such as oaks and maples, growing in temperate climates shed their leaves in the fall.
Why Leaves Fall Off Trees
Native American Legends About Fall
Native Americans in North America held great respect for the bear. One legend tells of the slaying of the Great Bear by celestial hunters. The blood from the bear rained from the sky onto the forests, coloring the some of the leaves red. As the hunters cooked the bear, the fat from the fires splashed out of the kettle and onto the trees, coloring the other leaves yellow.
This ancient legend comes from the Cherokee nation. There was a time when only plants and animals lived on the Earth. The Great Spirit told the plants and animals that they would receive great powers if they could stay awake for seven days and seven nights. Only a few creatures fulfilled the request and were granted these gifts: eternal color and the power of night. Trees such as pine and cedar were allowed to stay green. Other trees had to shed their leaves and sleep during the winter. Animals such as owls and mountain lions were permitted to wander at night.
Fall Fun Online
Maas, Robert, When Autumn Comes, Owlet, 1992
Maestro, Betsy, Why do Leaves Change Color?, HarperTrophy, 1994
Robbins, Ken, Autumn Leaves, Scholastic trade, 1998
Schnur, Steven, Autumn: An Alphabet Acrostic, Clarion Books, 1997
Silverstein, Shel, The Giving Tree, Harpercollins Juvenile Books, 1986
Sohi, Morteza E., Look What I Did With A Leaf, Walker & Co, 1993
Have students scroll through the Autumn Leaf Scrapbook to view pictures of leaves. If you have a color printer, print the pictures from the list.
Take the students on a walk through a park, forest, or preserve in your area. Bring notebooks with you. Collect several different kinds of leaves. Have students note the characteristics of the leaves in their notes. Ask students to identify as many of the leaves as they can. Upon return, have students make a scrapbook of the leaves. You might use an old photo album with clear stick pages or have students make scrapbooks using different colored tagboard or construction paper, binder rings, markers, scissors and clear contact paper. Have students label each leaf with the following information: type of leaf, date found, location found.
After discussion, have the children complete the activities from the Fall Haiku Lesson Plan.
Pose these questions:
Print out an outline map of the United States. Have students label each state and list the states that have areas of fall color. Use the Normal Peak Times for Fall Colors Map for reference. Students may use our blank worksheet or a sheet of paper for their list.
Projects To Do Together (Grades 3-12)
Photosynthesis (Grades 3-8)
Photosynthetic Pictures Are Worth More Than a Thousand Words (Grades 9-12)
I. Autumn Windows
II. Autumn Wreath
Try other neat fall leaf projects from the sites listed below.
Article by Louis Lewis, HLN Curriculum Development
|Last Updated on Monday, 20 February 2012 19:01|