# Rayan Lamp2) Pond-weed3) Meter StickStep by Step:1)Rayan Lamp2) Pond-weed3) Meter StickStep by Step:1)

Rayan Shafeek 9/11/2017 Teacher: Mrs. WilliamsAim:The aim of the investigation was to find out how different light intensities affects the rate of photosynthesis in Elodia (Pondweed).Introduction:Photosynthesis is the process used by plants to respire and convert light energy into chemical energy. Light is the catalyst for the photosynthesis reaction. The reactants in the chemical reaction for photosynthesis are Carbon Dioxide and Water. The products are Glucose + Oxygen + (Energy).Hypothesis:My hypothesis for the experiment was that the rate of photosynthesis will increase until it reaches a peak where the rate of photosynthesis can’t increase further acting in the same way maximum velocity would. I believe this as the rate of photosynthesis shouldn’t be able to increase continuously forever as the light gets closer as this is unreasonable and there should be a limit on the rate of photosynthesis from where a plant cannot photosynthesize faster.Method:Equipment/Apparatus:1) Lamp2) Pond-weed3) Meter StickStep by Step:1) Choose a starting distance (50 cm for us), and a common difference of which you will adjust the distance in this case (10 cm) and what your closest distance will be (10 cm).2) Then, place the pondweed in a beaker of water where a test tube is suspended on top, ensure it is in a dark room as we want to have maximum control over the amount of light that it receives.3) Afterwards, place the lamp from the farthest distance you have decided4) Watch how many bubbles arise during a certain time period as rate is found out by amount/time.5) After counting how many bubbles had risen, record it down in a data table.6) Move the lamp closer to the beaker by the common difference you had decided in step 1.7)Repeat steps 4-58)Repeat steps 6-7 until you finish recording how many bubbles rose at the closest distance.Variables:Independent Variables: Distance of light from ElodeaDependent Variables: No of Bubbles/ Rate of PhotosynthesisControl Variables: Amount of light from other sources, temperature of the roomRisk Assessment:Some of the possible dangers of this experiment were light harming the eyes due to the powerful lamps, to prevent this we wore goggles to help stop any harmful rays. There was also a possibility of glass being shattered which could result in major injuries. To stop this from being a possibility we had to ensure to handle all fragile items with care and sensibility. If anything were to accidentally be ingested the mouth would have to be rinsed straight away.Diagram:Data Table:Distance of Lamp from Elodea (cm) Number of bubbles in 5 minutes Rate of bubbles per minute10 12 2.420 10 230 7 1.440 6 1.250 4 0.8Graph:Conclusion:The data shows that as the distance of the lamp from the elodea increases, the rate of photosynthesis decreases. This suggests that the stronger the light intensity, the faster the rate of photosynthesis. This somewhat agrees with my hypothesis, if we were to move the lamp even closer, there is a possibility that it may have reached a maximum. The data from the experiment has provided proof of my hypothesis.Evaluation:Despite the test giving the expected outcome there were still many improvements that could be included to further add credibility to this test. The first improvement that could be made was to surround the beaker in water to stop heat from the lamp affecting the rate of photosynthesis, furthermore, we could have done several repetitions and worked out the average to prevent any anomalies that may occur and to check our data. Our test raises the question: How does temperature affect the rate of Photosynthesis? As we couldn’t completely