Download Take Home Lab - Dickinson ISD

Take Home Lab
Scientist:_____________________
Teacher:______________________
Due Date:_____________________
Forcing Fall
Background Information
Consider a hamburger. It contains meat that was once a part of a
cow. Where did the cow get the energy to make the muscle that
became meat? A cow must take in food, such as plants, that already
contain chemical energy. So where do plants get this chemical
energy? The SUN, through the process of photosynthesis which
translated means "putting together with light."!
Photosynthesis is a process in which green plants use energy from the sun to transform water, carbon
dioxide, and minerals into oxygen and energy (glucose). It is one example of how people and plants are
dependent on each other in sustaining life.
Photosynthesis happens when water is absorbed by the roots of green plants and is carried to the leaves
by the xylem, and carbon dioxide is obtained from air that enters the leaves through the stomata and
diffuses to the cells containing chlorophyll. The green pigment chlorophyll is converts the active energy of
light into a form that can be stored (in food) and used when needed.
Photosynthesis provides us with most of the oxygen we need in order to breathe. We, in turn, exhale the
carbon dioxide needed by plants. Plants are also crucial to human life because we rely on them as a
source of food for ourselves and for the animals that we eat.
Problem: Is sunlight necessary for leafs to be green?
Hypothesis: If a leaf receives no sunlight, then _______________________________________
_______________ because ________________________________________________________.
Design an experiment to prove or disprove your hypothesis. Be careful, you must have a control
group and have only one variable. Record your experiment in your journal per Lab Sheet
instructions.
Why do leaves turn colors in the fall?________________________________________________
________________________________________________________________________________
Why do you think some trees and other plants lose all their leaves in the winter?____________
_________________________________________________________________________________
EXTENSION(OPTIONAL): Find out why some plants are not green.
Additional Information on Photosynthesis to be added to Photosynthesis Lab at conclusion.
Did you know that a tree's leaves are green, orange and yellow -- even in summer? Most leaves include
the pigments of all three colors. It's just that the pigment chlorophyll. It covers the yellow and orange
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,
which produces reds and purples, isn't present all year long in most green leaves. It only shows up as the
nights get cooler.
As winter nears, less sunlight and less water 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.
Extra help for students in need:
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!