our science experiment

This experiment served to determine the affects of light intensity on the rate of photosynthesis in the underwater plant elodea. It was found that the rate of photosynthesis in the plant was accelerated when placed in


closer proximity to a constant light source. The rate of photosynthesis was measured by counting the amount of oxygen, a product of photosynthesis, generated by the plant. When the plant placed closer to the light source in a given time it generated more bubbles than when it was placed farther away from the light source.



Introduction:

Purpose: to determine the effects of light intensity to rate of photosynthesis.

Photosynthesis can be described by the following chemical reaction

Light + 6CO2 + 6 H2O -> Glucose + 6O2

With this in mind, the efficiency of photosynthesis during a specified time period can be calculated by measuring the amount of product formed from the above reaction. The plants tested in this experiment were underwater plants (Elodea) and the rate of photosynthesis was measured by the amount of oxygen produced by the plant through photosynthesis. The amount of oxygen produced was measured by counting of the number of bubbles that formed and floated to the surface from the submerged plant. The affects of different light intensities was determined by the amount of bubbles produced from various intensities of light.

Hypothesis: If photosynthesis is more efficient in stronger light, then more products will be formed faster in photosynthetic reactions.

Materials

1) Aquatic plant (Elodea)

2) Test tubes

3) Watch

4) Water (at room temperature)

5) Lamp (light source)

6) Knife/Scissors

7) Ruler



Procedure:

1) A segment of plant of approximately 8cm was cut with scissors.

2) The end of the stem at the site of incision was gently crushed.

3) The plant was fully submerged into a test tube filled with room temperature water.


4) That tube was set on a test tube stand.

5) A light source was placed 50 cm away facing the test tube.

6) The light source was powered on and observations were made.