Every year we see the leaves change color in the fall. Yet, why does this happen? Even further, what causes leaves to look vibrant in some areas and not so vivid in others? This fall lesson plan for science teachers will help both you and your students discover the answers to these questions?
The objective of this lesson is for students too learn how to make a hypothesis and investigate to find the answer. At the end of the lesson, students will learn why leaves change color?
Students need to have some knowledge of the terms photosynthesis and chlorophyll. A lesson on photosynthesis prior to this lesson is necessary. Also, giving kids a review on plant vocabulary might be good too.
Students will need hypothesis and investigation sheets. Try out one of these from homeschooling.about.com. Other materials include butcher paper or poster board, various fall leaves, plastic wrap, rubbing alcohol, cotton paper, shallow pan, hot tap water, tape, pen, plastic utensil and a timer.
Teachers should ask students: Why do leaves change colors in the fall? Students should write down answers on their hypothesis sheet. Also, this question should be written on a big piece of butcher paper. After students have had time to think, write down students’ answers on one side of the paper. Leave the other side blank for the end of the lesson.
Allow students to see a PowerPoint or read a selection about photosynthesis and falling leaves. Here is a good powerpoint on the subject by Meryl Spierenburg. For younger children, consider reading the book Why Do Leaves Change Color? by Betsy Maestro. Stop and pause to point out important words and discuss the main points.
Next, complete the chromatography experiment from miniscience.com. This lesson involves breaking up fall leaves in jars, covering it with rubbing alcohol and then using absorbent cotton paper to draw out the colors of leaves. Kids can really see how leaves contain many different colors. Depending on the grade level, the teacher should use his or her discretion when using rubbing alcohol. For younger children, this is better done whole group or small groups with several adults. Since it can take some time for the colors to be absorbed by the paper, it would be a good idea to do this before lunch or PE and then do the wrap up afterwards.
Wrapping it up
At the end, ask students to share why leaves change color in the fall? Students should complete the what I learned segment on their science experiment form. Chart answers on butcher paper to keep up on the wall so students can revisit the concept throughout the week. Possible answers may include that there is not enough light or water for photosynthesis to take place. Other important ideas are that the trees stop making chlorophyll and the other colors show more. To reinforce the process, allow kids to see this colorful animated page of why leaves change colors from tooter4kids.com.
For an extension for older students, have them look into when leaves change color in different parts of the world.
Beverly Hernandez Science Report Forms homeschooling.about.com
Meryl Spierenburg The Changing Leaves of Autumn slideshare.net
Betsy Maestro Why Do Leaves Change Color? September 1994