Yakir Starosta

IB Bio 12

Photosynthesis Lab

Research Question: Investigate the rate of photosynthesis of an elodea plant by measuring the amount of oxygen that is produced by it.

Variable:

Independent Variable:

The Independent variables are the different colors of cellophane paper that are wrapped around the 15 test tubes. The 5 different colors are green, blue, red, yellow and one without any cellophane paper.

Dependent Variable:

The dependent variable is the elodea plant as we are measuring the amount of oxygen that is produced by it through photosynthesis.

Controlled Variables:

  • Amount of water that is put into the test tubes – (This is going to be controlled by carefully filling up the whole test tube and carefully flipping it into the beaker with the water).
  • Amount of water in Beakers – (This is going to be controlled as the beakers are measurement beakers and I can determine when I have 200ml of water by looking at the side of the beaker)
  • Amount of cellophane paper around test tubes – (This is going to be controlled by using the same amount of cellophane paper to wrap around each test tube {12.2 X 7.4 cm each} )
  • The time that the test tubes are kept under the light – (I am going to control this by keeping the test tubes under the light for 8 days)
  • The length of the Elodea plant – (I am going to control this by using a ruler to measure out 11.3 cm of the Elodea plant for each trial)
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Apparatus:

  • 15 test tubes (15ml each)
  • Ruler
  • Scissors
  • Water
  • 5 beakers (250ml)
  • Elodea plant (15 pieces of 11.3cm each)
  • Masking tape
  • Light and light bulb of 100 watt
  • Cellophane paper (15 pieces of 12.2 X  7.4cm each)

Method (procedure):

  1. I gathered all my apparatus
  2. I then measured the test tubes and figured out home much cellophane paper I need in order to wrap each test tube (12.2 x  7.4 cm for each one)
  3. I took 4 ...

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