Photosynthesis - Plants' Greatest Gift

123 teachers like this lesson
Print Lesson

Objective

SWBAT to identify products and reactants of photosynthesis.

Big Idea

Engaging lesson that explores photosynthesis.

Engage

5 minutes

To engage students as we begin this lesson, I show this video on how dinosaurs became extinct. 

 

The reason I show this video is that most students have a  fascination with dinosaurs which will create automatic excitement and interest to beginning of lesson.  

After the video, I ask students to explain the reason why the dinosaurs that survived the meteor strike still ended up dying.  The answer that will connect to the lesson objective is - that due to the huge dust cloud, plants weren't able to go through photosynthesis which impacted food chain.

This is how I am building student understanding that plants are critical to life - during the age of dinosaurs and our own existence today.

Next, students create a First Word acrostic.  This goal of this strategy is to activate student connections to any knowledge of photosynthesis.  Students write the word PHOTOSYNTHESIS vertically, and are told to write full sentences, not single words or short phrases, building off of this first letter.  You may want to model this with a word/concept they have studied before.

Plants make their own food (example).

H

O

T

O

S

N

T

H

E

S

I

S

You will revisit this acrostic at the end of the lesson to assess if students have added to their prior knowledge.

Explore

20 minutes

In the explore stage of the lesson I conduct a teacher demonstration (Starch Test).  This demonstration has two objectives: 1) To show students that light is necessary for photosynthesis and 2) Demonstrate that plants produce food (starch) during photosynthesis. (MSLS-1-6).

Starch Demonstration Video by Jordan Mifsud:

Note:  The demonstration requires the plant to be in a dark location for 24 hours, to de-starch leaves.

During the video, students are required to take notes/observations and write down steps in their interactive notebook. It is important that students have a task related to a video, to insure that they will engage intellectually with it.  The notes should contain a description of the steps and the observations of the two different leaves.

Explain

20 minutes

After conducting the demonstration, I show students the following introduction to photosynthesis video. 

Following the video, students visit cK-12 where they read text on photosynthesis in conjunction with videos that visually represent the information.

Elaborate

10 minutes

To Elaborate, I extend students' understanding through this fascinating video on how we can "grow" fresher air in our own homes.  The intent is that this video reveals photosynthesis, which is a process that is invisible and abstract for us, real.

Evaluate

5 minutes

In this last section of lesson I assess student learning by revisiting the First Word activity we did at the beginning of unit.  This time they create a Last Word with the same word "PHOTOSYNTHESIS".  The Last Word provides a metacognitive opportunity for students to examine where they were in their thinking at the beginning of the lesson and reflect on how their present understanding extended or modified their initial understanding.

Plants produce glucose and oxygen during photosynthesis (example)

H

O

T

O

S

Y

N

T

H

E

S

S

Teacher Notes:  Once students complete word acrosstic I have them compare it with the one they completed at the start of the lesson.  The majority of students complete the acrosstic faster the second time because they have more knowledge to access than at the beginning.  I compare the results to assess how much students have learned during lesson.  

In the video below students discuss what they have learned during lesson and give a scientific explanation for photosynthesis (SP6).