Not All Leaves are Equal

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Objective

SWBAT observe leaf specimens and discuss plant adaptations for survival.

Big Idea

Students see leaves on trees and do not take time to wonder why the leaf is designed the way it is. This lesson allows students to look closely at two different types of leaves and make comparisons with those observations.

Setting the Stage

5 minutes

Many lessons in my curriculum focus on animal adaptations and survival, this lesson focuses on how plants adapt in order to survive in the wild.  I have two specific reasons why I teach this lesson. 

My first goal is to use local foliage for the students to observe, sketch (SP2) and measure (SP5). It will lead into a class conversation comparing our local plants to plants we know of in the jungles and construct explanations as to why the plant leaves are structured differently for survival purposes (SP6). 

Secondly, I want to provide the students with a hands on experience that will enable them the opportunity to observe in a more scientific way with the skills they have learned through out the course of the school year.  The students have used all the skills of sketching and measurement earlier in many lessons, however, this particular lesson will release much of my direction and allow them to lead their own direction in skills. 

I use leaves from plants in my own backyard and laminate them.  They laminate beautifully and make it much easier for students to measure and sketch what they are observing.  I am careful to choose two plants that have very distinctive leaf shapes in order to make the differences more obvious.  

Engage

5 minutes

I ask the children to gather on the rug with me.  When all the children are comfortable and sitting nicely, I begin my conversation with them by asking; "Does anyone remember when we talked about leaves and trees back in the Alpine unit?"  I am sure that most of the children will remember what I am referring to. My expectation will be that they will reference the deciduous trees we talked about. 

I ask them if they have ever looked at leaves on deciduous trees very closely.  

  • "What did you notice when you observed those leaves?"
  • "Did you notice any thing unusual and different about them?"   

After hearing any connections or thoughts the children share, I explain that we are going to make some observations of leaves.  I bring out a few of the laminated leaves and show them to the children.  

I explain to them that these leaves came from plants in my backyard.  I want them to realize that they will not be leaves from the jungles that we are observing.  

Explore

15 minutes

I pass out the leaf samples to the children. I am careful to make sure that the leaf samples are mixed up among the students.  I want to do this so to encourage any dialogue that may come up while they are making their observations will offer them strong examples to discuss.

At first, I don't offer anything other than the leaf itself.  I allow the children a couple of minutes to observe and wait. I am sure that someone will ask if they could use a tool to make some more detailed observations.  I probe a bit further to see what they might like to use to make that observation.  I anticipate a jeweler's loop will the be suggestion.  

I pass these out for the children to use and again will allow time for them to make their observations. As the children are making their observations, I am circulating and asking simple "what do you see?" questions.....

Inevitably, I know someone will ask, "Could we measure these leaves?" "Of course," I respond. "What would you like to use to measure....a standard tool or perhaps a more scientific one?"  Because we have now measured in many ways at this point of the school year, my expectation will be the students will answer, they would like to use rulers.  

The students find their rulers in their math tool boxes and begin to take any measurements they feel are necessary.  During all this work and exploration, I am very careful to only be observing and asking very simple questions.  I am doing this specifically because I want to see where the students will take this lesson without any guidance.  

Extending

15 minutes

This lesson is a really interesting one, in that there is really no explanation from me during the actual lesson.  It is, in my opinion one of those truly inquiry based lessons that is completely directed by the students themselves.  

When the students appear to have done all the observing and measuring they can to explore and discover the leaves, I ask one question to continue to encourage any suggestions the  students may have...."Could you do anything with this information you have just gathered?" I know without a doubt that someone will suggest they sketch their observations.  

When this suggestion is made, I hand out the small papers we use for sketching in our science lessons and the black pens.  We use black pens at the suggestion of a visiting scientist who shared with the children that she always sketches in her own journal in black pen. She shared with the students that sketching is not about having your sketch be exact in nature, but rather what you see and observe is what you sketch.  If it is in pen, you are not going to erase, you go with your instinct.  For this reason, we use black pens.  

Again, the children work on for another ten minutes.  I am continuing to observe the students and be a guide if need be.  However, the students truly are engaged and really do not need me in any way.  

Evaluate

10 minutes

After all the investigative work is completed, I become more involved.  I do this because I want to guide the work the children have just completed back to the original question that began the activity.  

I ask the children to look a their leaves and think about the weather we have in our area of the world. We live in an geographic region that is fortunate to experience all four seasons; each one distinctly.  I ask them to think about the leaves they observed and think about how those leaves survive in our weather? 

I anticipate they will share ideas or concepts about the leaves shapes and how they fall from the plants during the fall and cooler weather.  

I follow up with a question about the leaves we have read about during our reading lessons in the canopies of the jungles.  

  • "Are the leaves in the jungles similar to these leaves?"
  • "How are they different?"
  • "Does the size of the leaves help them in anyway?" 
  • "Why do you believe the leaves are so much bigger than our leaves here?"

All the questions are open ended questions and offer opportunities for the students to share their own thinking and even bring in any evidence from past learning or personal inferences they may have that support their thinking.  

Based upon the conversation that the class has and the ideas the students share, I know if they have been able to take the learning from the activity and mold it into an explanation.