Why Do Leaves Change Color?
Lesson 3 of 6
Objective: Students will be able to describe how chlorophyll makes leaves green by doing an experiment that pulls the chlorophyll out of a leaf.
I ask students to sit on the meeting place rug to listen to a book called Why Do Leaves Change Color? by Betsy Maestro and Loretta Krupinski.
I chose to read this book because the pictures and content do a great job of simplifying the process and vocabulary for kindergarten students. This book is still well above a kindergarten reading level so there will still need to be clarification on certain terms and processes as needed.
Guided Practice - Experiment
After reading the book, I ask students to come to the front of the room to participate in an experiment to see what colors are in certain types of leaves.
I have already set up the materials for the experiment. (see list of materials)
I go through each material and tell the students what each things is. Students are most likely to not know what rubbing alcohol is. I also explain why using a coffee filter for soaking up the alcohol is important as it is more fibrous and can soak up liquids as paper cannot.
Then, we proceed to go through the steps of the experiment. As I model a step, I use turn taking sticks to pull a name for a student helper. I remind students that sometimes when we use the sticks, not every student will get a turn. This helps eliminate the thought that they will all get to help do something and feelings aren't hurt.
First, we take the three differnt types of leaves and cut them into tiny bit into a glass. I have three helpers do this for me.
I ask, "Why do you think we are cutting the leaves into small bits?" I wait for responses and record them on the board.
Then we pour rubbing alcohol into each glass to cover the pieces of leaves. I have one helper for this and the helper wears safety goggles. I remind students that whenever we are working with chemicals, we need to stay safe.
The next step is to cut coffee filters into strip and to place one strip into each glass. I will have two helpers with this step.
I then explain to the students that we need to let the glasses sit for about an hour and then we can come back and see what has happened.
After getting the experiment set up, I ask the students to go back to their seats. While we wait for the experiment to work, we will work on writing a sentence that states what we think will happen with the experiment.
I have a sentence stem in the pocket chart to get the students started on the writing.
I pass out lined paper to each student.
Sentence stem: "I think that the filter paper will _________________________."
Since students need to wait the hour to see the results, I plan this lesson around a recess or a "special" class such as PE or Music. This is a great way to break up that time so that students are not waiting around for so long.
When the filter paper has been in the mixture for about an hour, I call the students back to the floor at the front of the room to see the results.
I pull the filter paper out of each glass and put it on a paper plate in front of the glass. I invite the students to come up and look at each filter paper.
To close the lesson, I ask the students to draw a picture of what they saw on each filter paper in their science journals.
Then, we talk about the results of the experiment. I also ask the students to compare their writing from earlier to what really happened on the filter paper to see if they were accurate.