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

Investigate a factor that affects the rate of photosynthesis.

Extracts from this document...


Aim: To investigate a factor that affects the rate of photosynthesis. Introduction: A measured piece of pondweed will be cut and placed into a beaker containing measured amounts of water and sodium hydrogen carbonate. A lamp will be shined on to the pondweed and the amount of bubbles that are produced from the plant will be counted. The lamp will be adjusted to different distances from the plant to try and obtain differing results. The point of this experiment is to find out how light intensity affects the rate of photosynthesis. The equation for photosynthesis is: 6CO2 + 6H2O = C6H12O6 + 6O2 Carbon Dioxide + Water (light energy) Glucose + Oxygen Light intensity will be the controlled variable looked at in this investigation. Increasing or decreasing the distance from the light source to the plant varies the light intensity. Fixed Variables Why the rate of photosynthesis increases or decreased from the amount of light energy absorbed is what is being investigated in this experiment. Pigments in the leaf such as chlorophyll absorb light energy. Chlorophyll easily absorbs blue light, in the 400-450 nm range, and also easily absorbs red light in the 650-700 nm range. ...read more.


But since the circle is expanding, the circumference increases and the same light energy is distributed along a greater surface. Preliminary investigation Before carrying out the real experiment, we carried out a preliminary investigation to see which factors we can improve to increase the effectiveness of the experiment. The most effective length of elodea was 10cm. This was because there is a larger surface area for photosynthesis to occur. The best light intensities were 5cm, 10cm, 15cm, 20cm and 25cm. This gave a wide range but not so wide that they would produce unreliable results. We also worked out that turning a measuring cylinder full of water upside down and put it over the top of the elodea in a beaker, better results were attained because less bubble escaped. Clipping the elodea to the bottom of the measuring cylinder helped to keep it from rising and therefore difficult to read the measurements. Method 1) Set up the apparatus as shown (in the diagram on separate paper) but leaving out the pondweed, measuring cylinder, test tube, water, and the sodium hydrogen carbonate. 2) Fill the beaker with 200 cm3 of water and 50 cm3 of NaHCO3. ...read more.


The CO2 content probably would not have affected the results further as we put much NaHCO3 into the water. Evaluation I think that the results we obtained were very reliable. There was only one anomaly showing that results were accurately recorded. I think that my method of carrying out the experiment was thorough but if I carried out this investigation again then I would carry out more preliminary work to ascertain why the results that our class gathered were unreliable and why our pondweed did not photosynthesise effectively, causing us to rely on secondary results. To extend this investigation, I would look at other limiting factors of photosynthesis and try to understand the link between the all. I could also attempt to look at the effects of different colours in light and see which colours worked more effectively than others. To improve the experiment, I could of attempted to block out foreign light better, as this may have affected my results. I could also look at better ways of controlling the temperature, maybe by using a beaker of water, as this would absorb heat but also is transparent. I would have to analyse this carefully however, as water can refract light and this would take me further into the effects of different light and light colours. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms 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 GCSE Green Plants as Organisms essays

  1. Marked by a teacher

    How the molar concentration of NaHCO3 (Sodium Hydrogen Carbonate) affects the rate of photosynthesis ...

    5 star(s)

    results, for instance ten large bubbles could have easily be counted as seventy small bubbles).

  2. This experiment involves using a photosynthometer to investigate how temperature affects the rate of ...

    I believe using a water bath would have allowed me to maintain the temperatures more precisely and save time as oppose to using a kettle. I recall whilst doing the experiment that the elodea specimen was placed somewhat close to the window.

  1. Experiment to Investigate the Effect of Temperature on the Rate of Photosynthesis in Elodea.

    Cyclic photophosphorylation only involves photosystem I. Light is absorbed by photosystem I and is passed to chlorophyll a (P700). An electron in the chlorophyll a molecule is excited to a higher energy level and is emitted from the chlorophyll molecule.

  2. Investigation To Find The Effect Of Temperature On The Rate Of Photosynthesis Of Elodea.

    d = ? ?(1000 ?5)? ? 15?14.90711985 Thus, one could predict that at distances less than ~15 cm (and therefore light intensities greater than ~4.5) the number of bubbles of CO2 produced by an Elodea specimen would be approximately uniform. When it comes to the slightly anomalous result shown on the LI vs.

  1. How temperature affects the rate of photosynthesis.

    The regeneration of RuBP also requires ATP, at the end of which ADP is reformed to be used in the light stage again. At the end of the light independent reactions, carbohydrates (products of photosynthesis) are formed. The most important raw material for these reactions is carbon dioxide.


    heatproof mat will need to be placed under all this to keep the Bunsen burner on something safe and also so that it remains stable and there is less risk of it falling over.goggles and a laboratory coat at all times to ensure safety and reduce the risk of any accidents.

  1. The aim of my investigation was to determine how limiting factors would affect the ...

    Sclerenchyma is found in stems and also in leaf veins. It also makes up the hard outer covering of seeds and nuts. Collenchyma: the cells have thick walls that are especially thick at their corners. These cells provide mechanical support for the plant.

  2. Aim: To investigate a factor that affects the rate of photosynthesis

    Plant- Different species plants have different photosynthetic rates due to the different leaf structures of the plants. Even plants of the same species may have slightly different rates of photosynthesis since there may be more or less chlorophyll in the leaves to absorb light.

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