Plant Actions

Angelica Wright                Robert Fulton
6131 S. Campbell               5300 S. Hermitage
Chicago IL 60629               Chicago IL 60609
(773) 436-2149                 (773) 535-9000

Part A-Photosynthesis
Objectives:

To define the term photosynthesis. 
To practice iodine test for the presence of starch in leaves.
To compare the results of iodine test of two leaves one that has been exposed to 
   sunlight and one that has not. 

Materials needed:

CAUTION! This activity uses heat and requires safety training and supervision! 

small dish     iodine     eye dropper     plant      sauce pan     alcohol     
beaker     tweezers     black plastic     tape     scissors 

Strategy:

1. Tape plastic around some of the leaves of a geranium plant.  Place the plant 
in a light place for two days.  Then pick a wrapped leaf, and one is not 
wrapped. 

2. Heat water in a sauce pan, warm alcohol in a beaker.  Dip both leaves in hot
water and then leave them in the alcohol.  When the leaves are almost white, add
iodine to them.

Results:

The leaf that was not wrapped turns a dark color, but the leaf that was wrapped 
remains the same.  The fact that the wrapped leaf did not change color shows 
that it did not have any starch.  The change in color in the unwrapped leaf 
indicates the presence of starch.  The difference between the leaves is the 
exposure to sunlight.  It goes to show that sunlight is necessary for the 
manufacture of plant food.  This process in which plants use sunlight and other 
natural resources to make their food is called photosynthesis.  The green color 
or pigment is called chlorophyll.  The light is absorbed by the chlorophyll 
which also transfers the energy thus derived and in some brings about the 
photosynthetic reactions. 

Part B-Water Transport
Objectives:

To show hands-on how water is transported through the stem to other parts of the 
plant. 

Materials needed:

     glasses     food coloring     fresh carnations or celery with leaves

Strategy:

Pour five to seven drops of food coloring to each glass then add some water to 
each glass.  Trim the flowers or celery stem so that the tubes will be freshly 
open and not clogged.  Split the stem of one of the flowers.  Put the split stem 
goes into each of the two glasses that hold two different colors.  Put the 
unsplit flower into one of the glasses with colored water.  Leave flowers at 
room temperature for an hour so. 

Results:

The flowers will slowly and gradually change color.  The flowers in each glass 
change to the color of the food coloring in the glass.  The flower with the 
split stem will change into two different colors, one each side of the flower.  
This process shows that the stem of a plant not only holds the plant or tree in 
an upright position, but it also helps in the transportation of foods and 
liquids from one part of the plant to other. 

Performance Assessment:

Findings can be judged by the science journal entries, or by oral or written 
reports.  These activities are PASS/FAIL only.