Lesson LEAFlet

Teaching/Learning Resources

Subject Area: Chemistry
Grade Level: Fourth Grade
Curriculum Integration: This lesson integrates leaves and chemistry.

Lesson Objectives:
1.  The students will know that leaves contain colored pigments.
2.  The students will know which leaves contain the most pigments.
3.  The students will collect a variety of green leaves in order ot separate their pigments through paper chromatography.
4.  The students will place their leaves on filter paper and roll a coin over them to extract pigments.
5.  The students will lower each peice of filter paper into a beaker of fingernail polish remover, which contains mostly acetone, that will separate pigments.
6.  The students will watch as the fingernail polish remover ascends carrying the pigments to different heights on the filter paper.
7.  The students will look at the pigments that have been separated.
8.  The students will draw their green leaves and then they will draw them with the colors they might be in autumn based on the pigment strips.
9.  The students will look at leaves differently when autumn arrives, understanding that the change colors because they have pigments in them.
 

Materials Required:  A variety of green leaves, strips of filter paper cut 3/4 inches by 4 inches, coins, tape, pencil/stick, beakers, non-oily fingernail polish remover (contains acetone), construction paper, and
                                 crayons.
 

Lesson Outline:
1.  The teacher will hold up one green leaf and one multi-colored leaf for the students to see. The teacher will ask the students if they have ever wondered what makes green leaves change color in the fall.
2.  The teacher will tell the students that green leaves are filled with various pigments that cause them to change color in the fall.
3.  The teacher will tell the students that we are going to look at a variety of green leaves in a chemical called acetone that will allow us to see their different pigments.
4.  The teacher will explain what paper chromatography is.
5.  The teacher will have the students work in groups of two or three (they should already have collected a variety of green leaves from home).
6.  The teacher will pass out the strips of 3/4 by 4 inch filter paper.
7.  The students will place their leaves on the filter paper and roll a coin over it to crush the leaf tissue.
8.  The students will repeat this several times, rolling the coin on a fresh peice of the leaf over the same place on the paper.  There should be one strip of filter paper for each leaf collected.
9.  The students will tape the strips of filter paper to a pencil or a stick and lower them into non-oily finger nail polish remover (containing acetone) to bring out the pigments in the leaves.
10.  The students will watch as the acetone in the fingernail polish remover causes the pigments on the filter paper to rise.
11.  After the strips of filter paper have dried, the students will look at the pigments that have been separated.
12.  The students will match the strips of filter paper up with the leaves that they came from.
13.  The students will draw a picture of their green leaves and then, using the filter paper with pigment on it, they will draw a picture of what their leaves might look like in autumn when they have changed
        colors.
 
 
 

Extension Activities:
 
 

Submitted by:  Nina Bish, Ed McMahan, Theresa Tssario, and Brent Vargo
 

For:
Lake Erie Arboretum at Frontier Park

Send plans to:

Dr. Charles Elliott, Director
       Educational Technology
       Gannon University
       109 University Square
       Erie, PA   16541