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

Photosynthetic rate and light intensity.

Extracts from this document...


Biology Coursework-Photosynthetic Rate and Light Intensity PLAN Aim - to investigate the effect of light intensity on the rate of photosynthesis in a plant. Prediction - Plant cells use light to help them to make food by photosynthesis. They trap the energy in the sunlight and use it to convert carbon dioxide and water into sugars. The chemical reaction that takes place is: Light energy 6 CO2 + 6 H2O C6 H12 O6 + 6 O2 (from air (from soil Chlorophyll in sugar via stomata) via root hairs Chloroplasts and xylem) Substrates Products All plants need light to photosynthesise otherwise they will die. The photosynthetic rate is affected by the light intensity because when the light falls on to the chloroplasts on the leaf, it is trapped by the chlorophyll and therefore makes energy available for chemical reactions in the plant. So as the light from the bulb shines on to the plant, more energy is absorbed and is available for chemical reactions, more photosynthesis takes place. From this information, I predict that as I increase the light intensity from the bulb, the photosynthetic rate will also increase at a directly proportional rate until it reaches a point where increasing the light intensity will no longer affect the photosynthetic rate. ...read more.


In this experiment, I am investigating why the rate of photosynthesis increases or decreases with the amount of light energy absorbed. I will keep this constant by using the same lamp during the experiment. ==>Carbon Dioxide-This can affect the photosynthetic rate because the more of it in the air, the more that can diffuse into the Elodea. To keep this variable constant, I need to put a fixed amount of sodium hydrogen carbonate into the boiling tube along with the water and the plant. OBTAINING EVIDENCE I carried out my plan to the best of my ability and these are the results I came up with: Independent Variable (Distance - mm) 1st Dependant Variable reading (O2 bubbles) 2nd Dependant Variable reading (O2 bubbles) 3rd Dependant Variable reading (O2 bubbles) Average Dependant Variable 20 10 12 11 11 40 8 7 8 7.67 60 5 5 6 5.33 80 3 5 5 4.33 100 1 3 3 2.33 I used my three sets of results, which are in the centre three boxes, to create average results in the column on the far right. I am going to use theses results to draw my graphs. ...read more.


I did not really allow time for the elodea to equilibrate to the light intensity and so the number of O2 bubbles was probably less than expected. I was also unsure as to when to start my timing, whether it be as soon as I see a bubble produced or just at a random point but whatever I did, I would have to keep constant to make my results reliable. I decided upon doing when I see a bubble rise so then I would know that the Elodea has at least equilibrated a little bit. To improve the quality of the data, I could perform the experiment using a syringe and capillary tube, so that the bubbles form one bubble and then I can measure the volume of the bubble. I can do this because I know the size of the tube so it just depends on the length. This is how it would be set up: If I was to do this again, I would make sure I give the plant the time it needs to equilibrate and use the improvements I suggested. I would maybe also extend my range of results to a further distance, although the reason I didn't this time was because the number of oxygen bubbles produced was so low I didn't think anymore would be produced at a lower light intensity. ...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. Experiment to Investigate the Effect of Temperature on the Rate of Photosynthesis in Elodea.

    achieve reliable results, each reading should be repeated preferably 3 times, with the results averaged.

  2. Mangrove Soil Analysis

    37.60 21.45 31.00 24.74 22.59 25.56 4. Mass of Evaporating Dish and Soil After Strong Heating 86.14 60.83 77.94 66.34 69.67 70.53 5. Mass of Heated Soil (4 - 1) 36.52 19.21 29.85 22.83 21.45 25.22 6. Mass of Organic Matter (3 - 5) 1.08 2.24 1.15 1.91 1.14 0.34 7.

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

    Fill the beaker with 450 cm3 of water and 50 cm3 of NaHCO3. 3. Select 1 or 2 pieces of pond weed each roughly 5-10 cm long and cut off the stems. 4. Place the pond weed in the beaker and secure the funnel upside down over (on top of)

  2. Investigating the effect of Light Intensity on Elodea.

    26 26 60 17 18 16 17 From this we can see that there is a definite correlation. As the distance from the plant increases the number of bubbles decreases. For my final experiment I intend to record results from the following distances: 50, 45, 40, 35, 30, 25, 20, 15, 10, 5.

  1. Investigate the effect of light intensity and the colour of light on the rate ...

    Connect the end of the pondweed to the apparatus. Insert a thermometer into the beaker, and record the temperature at the beginning and end of each experiment, merely as a safety measure against an important rise in temperature, which is not expected.

  2. How temperature affects the rate of photosynthesis.

    Group Class Average of Average rate of O2 released (mm3/min) 1 2 3 4 5 6 7 8 9 10 11 12 13 0 0.40 0.10 0.07 0.10 0.13 0.08 0.10 0.10 0.10 0.40 0.13 0.27 0.40 0.18 15 10.59 3.72 8.20 4.32 1.61 2.71 3.12 13.04 1.91 5.50 2.01

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

    The 'water table' is the level at which there is naturally occurring water in the soil. The higher up the pingo you go, the smaller the amount of water because the soil and bedrock have been lifted up and away from the water table.

  2. The aim of this experiment is the effect of temperature on the rate of ...

    From A2 level we learnt about the two different types of photosynthesis and how they occur. The first type of photosynthesis is the LIGHT-DEPENDENT REACTIONS, whereby the plant needs light to be able to carry out photosynthesis to form a carbohydrate and oxygen.

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