Photosynthesis...How it All Works

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SWBAT explore the concept of photosynthesis.

Big Idea

Leaves and plants are essential to the world, but just how do they work? This lesson demonstrates for students the process in a simple way.

Setting the Stage

5 minutes

This lesson follows the lesson on leaf observations. Both lessons fall in the unit on the Rain Forests and Jungles of the world.  In fact, the lessons within this unit focus on concepts that relate to plants and foliage within biomes.  The catalyst of the Rain Forest plants is simply a vehicle to bring out the plant learning.  

I specifically taught the lesson on observations before coming to this lesson because I wanted the students to observe the leaf up close and make the connection that all leaves can be different, but play the same role in the world of nature.  Demonstrating that all plants need water and light to grow (2-LS2-1). 

It should be noted, that in no way do I expect my students to completely and absolutely grasp this concept to a mastery level.  I want to introduce this topic and concept and hope that it will establish background knowledge for later learning.  


5 minutes

I prepare the children by asking them to look at the screen.  My Power Point is ready and prepared for the children. I use power points in almost all of my teaching lessons. They help me to keep the children focused on an element that can bring in many factors: photographs, language, vocabulary, and technology.  All of these, help students in all categories of learning.  

Slide one is the title slide that introduces the lesson...The title is Plant Survival.  I could have used the word photosynthesis as the title, however, I really want to make it simple. I also do not want to introduce the word too early. I want to carefully build up the learning and help the children to construct their own meaning of the process; constructively. 

Slide two poses a question I want the children to think about and ponder. The photographs on the slide are all pictures of plants that survive in the jungles. After posing the question and allowing the children a minute or two of quiet thinking time, I move to slide three.  Slide three explains it is time to share in a team.  I use team talk often in my classroom. It is a powerful teaching tool in eliciting classroom discourse and dialogue between students. 


15 minutes

I move to slide four which has a statement that "Humans and animals need food to survive." Then moves into another question for the students to puzzle through. "How do humans and animals get food to survive?" I allow the children a couple of minutes to think this through. Moving on to the last question, "How do plants get food to survive?" 

Because this concept is a challenging one, I opt to guide the children through the exploration phase with a class discussion.  I believe that it is more appropriate to do have this conversation than to construct an investigation that may loose the power in the lesson because it could take too long with time to demonstrate the effects.  

The children have many theories and I listen and allow them time to share their ideas.  Many of them even have a beginning concept of what the process looks like. I ask them to watch the video clip of a venus flytrap eating an insect.  I do this because it is a plant eating and I want to demonstrate for the students that not all plants get food in this manner.  There must be other ways.  

Of course, the video clip is awesome and the it creates some excitement when the children watch the venus flytrap. When the excitement dies down, I ask the children, "If all plants cannot eat like this, how can they survive?" 


After this, I move to slide six which explains, simply that plants do not eat like this.  At this point, I introduce the word photosynthesis. 




15 minutes

This is a big question and has a complicated answer.  It is important that children have a basic understanding of how this process works in nature.  I am concerned with my own explanation and the possibility that I could easily mislead or confuse a student if I do not carefully and accurately explain the process correctly.  For this reason, I opt to read a children's book that is recommended by NSTA (National Science Teachers Association) Living Sunlight.  It is a beautiful book and really explains the process well.  

I read the book to the children, reminding them that we will read it through completely and then go back and discuss what we learned from the writing.

As I finish, the children have many questions. I explain that I would like them to look at the screen one more time.  I share with them, that I believe what we will see on the screen will explain many of their questions.  

Slide seven has just the words, "Let's talk..." (My power point has slide 7-12 timed to add each element as I click.  I have separated this for teachers to use in a PDF and get the same effect simply by changing slides.  Each slide will add the new element as you click).  

It begins with the word "photo" explaining it's meaning.  I include a picture clue along with the language.  This is for the visual students who need that extra trigger.  I proceed through the same process adding each element to explain what the word photosynthesis means.  

I use slides 14-16 to slowly and carefully continue to explain the process.  Many of the children will make references back to the book we read earlier.  



20 minutes

I want to see how much the students are able to take the new (and complicated) information and apply it in a simplified way.  I bring to each child a blank picture that has only a tree and the sun on it. I explain to the children that I would like them to color the picture.  I provide them with about ten minutes to color their pages.  

When the coloring is finished, I pass out the second page. Explaining that I would like them to cut out the labels and place them on their papers where they believe they would best go.  I remind them not to glue any labels, just place them on the page.  

I want to offer the children a chance to apply the learning we have just completed.  Keeping in mind that this concept if very hard to understand.  My hope is that they will get some of the labels placed in the correct placement of the process. 


10 minutes

After all the children have completed the coloring, cutting and organizing. I circulate throughout the classroom observing their work.  

I ask questions about placement.  Most of the children correctly place the labels for the sunlight and water.  The other labels are bit trickery. They know they must be on the page, but they are still not solid in where the placement should go.  

I offer them one more opportunity to check their work by showing them slide 19.  I explain why each element is placed on the diagram where it is one more time.  Again, this concept is very difficult and I am not expecting mastery.