Photosynthesis Model

We can use objects and ideas to model the processes of photosynthesis and respiration.  

In each model, the key part is for us to know how it is like photosynthesis or respiration.  

We connect our models to the real-world.

Part 1: Race to the Sun Challenge

The goal of this challenge is to model that plants can only photosynthesize when light is present, and that chlorophyll is the part of the plant that works the hardest.

• One student, the sun, stands at one side of a playing field and at their feet is a collection of playing chips. Each chip will represent an amount of solar energy.

• The rest of the class is divided into teams that are at the opposite end of the field. In those teams, two students are chosen to be runners (one will be 'Chlora' and the other is 'Phil'... get it... together they make chlorophyll... ha...).

• Okay, the runner's job is to relay back and forth to the bucket to collect the solar energy. Chlora and Phil take turns running.  Each time they bring a chip back, their group gets to move one step closer to the sun (to model that the plant is growing with the solar energy).

• Every time the sun turns her/his back, it is night and everyone rests, then when the sun faces forward again, play continues. 

• The first team to reach the sun wins. 

Debrief questions:

1. What part of your team worked the hardest to help you photosynthesize? 

2. What time of day can you photosynthesize? 

3. How might the other pieces of the plant rely on the chlorophyll?

4. How did you rely on Chlora and Phil? 

Ideas for modification:

  --maybe instead of reaching the sun we could adapt it so that the plant grows to some amount that more closely models the real world... like a blossom stage? 

 --play a few rounds so we can disperse roles and be more inclusive

 --have sun distribute one energy packet to individual "Chloras" and "Phils," then have measuring tapes or football field hash marks to be able to quantify the steps forward.

Part 2: Equation Model

Set the cards out first to show photosynthesis, then to show respiration.

Have the teacher check each equation before you move on.

Card Inventory (you need all 11 of the following to be back in the envelope):

• 1 6CO2

• 1 6H2O

• 1 C6H12O6

• 1 O2

• 3 "+" signs

• 1 "->" sign

• 1 "Chlorophyll"

• 1 "Energy"

• 1 "Enzymes"

Part 3: Gummy Bear Model

You will use gummy bears and toothpicks to model photosynthesis and respiration.

First, observe the molecular diagrams of photosynthesis and respiration:

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Respiration:

         C6H12O6    +    6O2 ---(enzymes)---> 6CO2    +    6H2O    (energy is released)

Before doing the model, answer these questions in your journal:

1) In photosynthesis and respiration, are any atoms created or destroyed?  ____

2) Are photosynthesis and respiration chemical or physical changes?  _____________ How do you know?_______________________________

3) You will get colored gummy bears to represent the following atoms:

 * Carbon = green   * Oxygen = red/orange   * Hydrogen = white/yellow

You also get toothpicks. What do the toothpicks represent? _______________

4) In sugar, the energy is stored in the __________________________________

Get:

• 6 green (carbon)

• 18 red/orange (oxygen)

• 12 white/yellow (hydrogen)

• 24 short toothpicks

• 7 long toothpicks

Do:

1. Make 6 CO2 and 6 H2O – have teacher check, then do photosynthesis.

2. Have teacher check, then do respiration - have teacher check after.

3. Clean up (put gummy bears and toothpicks back in bags and check to make sure all items have been returned to the bag). Then answer questions 5-7.

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Respiration:

         C6H12O6    +    6O2 ---(enzymes)---> 6CO2    +    6H2O    (energy is released)