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Photosynthesis - A Simple Experiment

Photosynthesis - A Simple Experiment

Goals: Students now know that for photosynthesis to occur, a plant needs sunlight, water and carbon dioxide. In the experiment, students will observe if plants can thrive without all three of the essential elements for photosynthesis – water, sunlight and carbon dioxide.


  • three empty, peeled 2-liter bottles
  • scissor
  • scotch tape
  • pitcher with water
  • box in which the planter can fit (and a closet or dark cabinet in which to put bottle 3)

1. Cut the tops off the plastic bottles.
2. Dig up three small plants (about the same size) from the schoolyard with their surrounding dirt.
3. Place each into one of the 2-liter bottles.
4. Place two of the planters in the sunlight and one under a box in a closet, (so that it gets no sunlight).
6. One of the planters in the light will be Bottle 1 – the control bottle receiving water daily and sunlight.
     Bottle 2 (in the sunlight) gets no water. Bottle 3 (in the dark), gets watered every day, but receives no sunlight.
7. After 10 days, look at the terrariums side by side. 

Observation: Can you see any differences between the plants?

Thinking Moment: Is this the result you expected? Explain and Discuss.


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