• 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...

Introduction

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.

Middle

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.

Conclusion

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)

    I will then repeat steps 3-4 for this concentration, until I have finished recording the number of bubbles that appear for all the concentrations I will use.

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

    alters the shape of the active site, thus a better more tight fit. Once the products have been released, the enzyme and active site returns to its original shape. Enzymes work on the basis of kinetic theory. In order that enzyme and substrate molecules bind, they must collide with the right amount of energy and at the correct angle.

  1. How temperature affects the rate of photosynthesis.

    which reacts with water to form carbon dioxide. This would make it available in excess for the plant to use. Also carboxylation requires the action of an enzyme (Rubisco). Again temperature will have a direct affect on the functioning of the enzyme Rubisco and therefore the rate at which photosynthesis occurs.

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

    This explains why graphs cover a small temperature range. When light intensity is varied and all other factors remain constant, the rate of photosynthesis increases linearly with increased light intensity over a range of low intensities. The light intensity is said to be the limiting factor.

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

    As the amount of CO2 available increases, the rate of p/s increases, until the plant is photosynthesising as fast as it can - the CSP - CO2 Saturation Point. If both CO2 and light supply are increased together, the rate of p/s will level out.

  2. Absorption Spectrum of Chlorophyll.

    This is the same thing that happened with the spinach. The first three extracts had blue absorbance maxima of (430 ? 3) nm while the fourth extract had a maximum of (428 ? 3) nm. The red absorbance maximum ranged from (662 ?

  1. An Investigation into Species Diversity with distance along a Pingo.

    The oxygen is then reduced to water. The transfer of electrons down the transport chain makes energy available, which is used to convert ADP+Pi into ATP. Below are predicted graphs for the change in light intensity and water content with distance from the top of the pingo.

  2. INVESTIGATING HOW TEMPERATURE AFFECTS THE

    When using the colour meter I will measure the absorbency of the distilled water and then compare this to the different beetroot concentrations. I will then need to measure the solutions against a colorimeter I will use a colorimeter rather than a chart as the sensor is sensitive to light

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