• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Factors Affecting the Rate of Photosynthesis Lab

Extracts from this document...


Factors Affecting the Rate of Photosynthesis Research Question: How does light intensity affect the number of bubbles produced by a branch of elodea in 400mL of sodium hydrogen carbonate (4g) solution in 30 seconds? Variables: * Independent: light intensity * Dependent: number of bubbles produced in a 30-second period * Control: availability/amount of water (I will assume that the elodea has a consistent volume of water available at all points on its surface), type of plant (I will be using a piece of elodea), size of elodea (the sample of elodea is a branch from a larger piece of elodea, about the same size as other branches from it), availability of carbon dioxide (the elodea is in a 400mL solution of 4g of sodium hydrogen carbonate), mass of plant (I will be using one piece of elodea for all my trials), type/color of light source (I will be using a single 40W bulb that emits what I will assume to be white light for all of my tests), angle/position of light (I am going to let the bulb rest in one spot, and for each test I do, I will move the beaker containing elodea and sodium hydrogen carbonate solution closer to or further away from the light source), amount of outside light (the ...read more.


I can tell that they are significantly different because the result (the comparison of the means of the two light intensities) of the t-test showed was higher than 2.78. So, it is with 95% confidence that I can say that the lowest-light-intensity-tested results were significantly different than the highest-light-intensity-tested results. As shown in the graph above, the rate of reaction increases steadily, until the light intensity reaches somewhere above 300 lux, at which point there is a much steeper slope in the graph. Also, as shown by the tests at 420 lux and 640 lux, the graph begins to plateau very quickly after the previous steep incline. This means that at a point around 300 lux, the photosynthetic reactions are very responsive to increased light intensities but at some point before 400 lux, increased light intensity bears less response. This means that the maximum photosynthetic rates were reached, or more likely, that some other factor limited the rate of reaction. Evaluation: Though I believe I had a successful experiment and obtained accurate results that supported my hypothesis and my knowledge of photosynthesis, there were numerous limitations and improvements that could be made to this experiment. ...read more.


If this happened, the results I obtained would be a little bit distorted. A solution to this limitation would be to do all the experimenting behind a poster board that blocks out as much ambient/background light as possible and to have students do experimenting in different rooms or areas. Oxygen used in plant respiration or dissolved into water Some of the oxygen produced may be used for other processes, including respiration or dissolving into the water. This would have only a very small effect on my experimenting and is impossible to control in an experiment where the plant is submerged in water. Replication In my experimenting, the time constraints and continuous modification of my experiments allowed me only to obtain three trials per light intensity and to do 5 different light intensity tests. The impact this has is that because of the relatively low amount of replication, the results are not extremely convincing, though there is evidence of support of my hypothesis. To help get rid of any anomalies and extend the range of data tested, this experiment could have been done with a wider range of light intensities and more trials per light intensity could have been performed. Kyle Hovey ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Biology essays

  1. Biology HL IA - Photosynthesis of elodea lab report

    Test tube with the Elodea was put into the beaker filled with water in order to prevent the change in temperature due to the heat of light lamp. Thermometer was placed into beaker to measure changes in temperature. The photosynthometer was set up like shown in Figure 1 (below).

  2. The effect of light intensity on cyclosis on Elodea leaf cells

    18.06 12.46 130 5.93 7.20 10.43 22.47 15.62 12.27 130 5.79 8.32 10.59 Cinys results: 18.59 12.31 No entry 130 6.99 10.56 No entry 12.13 12.42 No entry 130 10.72 10.47 No entry 14.84 10.08 No entry

  1. Investigating an enzyme-controlled reaction: catalase and hydrogen peroxide concentration

    The reasons for this are that there are number of variables that influence the decomposition of hydrogen peroxide in the presence of Catalase. Some of which can be classified as limiting factors i.e. the reaction is dependant or "limited" by their availability, to be able to function effectively; these include enzyme concentration, temperature and substrate concentration.

  2. Experiment - Influencing the Rate of Photosynthesis with Light Intensity and Carbon Dioxide Concentration

    A 5 cm was measured for the distance between the plant and the lamp. For 5 minutes, recorded with a stop watch, the test tube was observed for bubbles which were counted. The data was recorded. This same procedure was done again for a second trial.

  1. Environmental Factors affecting plant growth

    tube holders to hold all the tubes, markers to mark the tubes, graph paper to measure surface area of leaves, pipettes to mix solutions and flasks to mix solutions in. The following diagram explains how the experiment was set up and also the method used to carry out the experiment.

  2. Bio lab - Oxygen Consumption in germinating and non-germinating seeds

    Temperature (�C�1�C) Time (min) Control (Beads) ml�0.01ml Germinating Seeds ml�0.01ml Non-germinating Seeds ml�0.01ml 21 0 0.925 0.805 0.91 5 0.89 0.71 0.89 10 0.865 0.36 0.875 15 0.84 0.25 0.855 20 0.83 0.22 0.84 25 0.815 0.19 0.83 30 0.79 0.15 0.815 Raw Data Table 8: The volume of the water level

  1. affect of light intensity on rate of photosynthesis

    2 4 6 8 pH 11 11 11.5 12 Table2 shows the pH taken from beaker B, which was at 40 Cm distance from the lamp at the time interval 2, 4, 6 and 8 minutes. Graph 2 Graph 2 shows the result from table 2 on graph Table 3 60 cm from the lamp Time (min)

  2. Plan for an experiment - How does temperature affect the rate of photosynthesis?

    Below 10°c and above 35°c, I expect the volume of oxygen to decrease, as there isn’t enough energy for the enzymes to collide below 10°c and the enzymes active sites would start to denature around and above 35°c. Independent Variable: Temperature between 5 – 40 degrees in intervals of 5 (°c)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work