Do Trees Really Die in the Wintertime?

An Internet Web quest for 3rd grade. By Anthony DelCotto and Julie Saccente

 

Introduction:  All summer, with the long hours of sunlight and a good supply of liquid water, plants are busy making and storing food, and growing. But what about wintertime? The winter months are cold and the ground is frozen. Do the trees that look bare actually die or is something else at work? Have you noticed anything different about the trees as they prepare for winter?

 

List some ideas about how trees may prepare for winter: __________________________________________________________________________________________________________________________________________________________________________________

 

 

Trees in the summer are bright green and look very lush. For months and months the warm temperatures and abundant rainfall create a wonderful environment for the tree to prosper. In the fall, the leaves miraculously change their color. Why does this happen? We need to find out how and why this green leaf

 

  begins to change color!   During autumn, green

 

 

leaves like this begin to look like this:

 

And some even become yellow, red, and orange!!

 

Task:  It is September and you are a tree that needs to begin to prepare for winter.  You notice that many other trees start to change color.  You want to do this as well, but are unsure as to what processes will be involved to change the color of your leaves. In order to find out, please research the following questions to determine why leaves change color:

·        Why do leaves have a green color?

·        What factors are involved in changing the color of a leaf?

·        What processes inside the leaf breakdown in the fall?

·        What kinds of trees lose their leaves in the wintertime?

·        What process does a plant use to make food?

·        When you have finished researching about trees and why they change color, let the teacher know you are ready to begin the next exercise.

 

These are websites that you should use to complete the task above:

 

http://www.sciencemadesimple.com/leaves.html

 

http://www.dnr.state.wi.us/org/caer/ce/eek/veg/trees/treestruecolor.htm

 

http://mt.essortment.com/leaveschanging_resv.htm

 

http://www.pbs.org/americanfieldguide/topics/plants/#

            Look for the movie “Why Leaves Change Color”

 

Conclusion: Once the task is completed you will understand why trees prepare for winter. You will understand the processes involved and the factors that cause a tree to change the color of and lose its leaves. You will also have a better understanding of the complexities involved within the chemical actions of a leaf. Lastly, you will know whether or not a tree is alive or not in wintertime.

 

 As a follow up activity, here is a project that can show students that green leaves have certain “ingredients” in them that help the leaves change color.

 

PROJECT  - Separate Colors in a Green Leaf using Chromatography  

NOTE:  Only the teacher should be handling the hot water and alcohol.

What you need:

leaves, small jars (baby food jars work well)

covers for jars or aluminum foil or plastic wrap

rubbing alcohol, paper coffee filters

shallow pan, hot tap water, tape, pen

plastic knife or spoon, clock or timer.

What you do:

  1. Collect 2-3 large leaves from several different trees. Tear or chop the leaves into very small pieces and put them into small jars labeled with the name or location of the tree.
  2. Add enough rubbing alcohol to each jar to cover the leaves. Using a plastic knife or spoon, carefully chop and grind the leaves in the alcohol.
    SAFETY NOTE: Isopropyl rubbing alcohol can be harmful if mishandled or misused. Read and carefully follow all warnings on the alcohol bottle.
  3. Cover the jars very loosely with lids or plastic wrap or aluminum foil. Place the jars carefully into a shallow tray containing 1 inch of hot tap water.
    SAFETY NOTE: Hot water above 150 F can quickly cause severe burns. Experts recommend setting your water heater thermostat no higher than 125 F.
  4. Keep the jars in the water for at least a half-hour, longer if needed, until the alcohol has become colored (the darker the better). Twirl each jar gently about every five minutes. Replace the hot water if it cools off.
  5. Cut a long thin strip of coffee filter paper for each of the jars and label it.
  6. Remove jars from water and uncover. Place a strip of filter paper into each jar so that one end is in the alcohol. Bend the other end over the top of the jar and secure it with tape.
  7. The alcohol will travel up the paper, bringing the colors with it. After 30-90 minutes (or longer), the colors will travel different distances up the paper as the alcohol evaporates. You should be able to see different shades of green, and possibly some yellow, orange or red, depending on the type of leaf.
  8.  Remove the strips of paper, let them dry and then tape them to a piece of plain paper.

Conclusion:  Once the project is completed you will know what color your leaves will turn to prepare for winter. 

 

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