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

Investigate the factors that affect the rate of photosynthesis.

Extracts from this document...

Introduction

Introduction Photosynthesis is the chemical process, which takes place in every green plant to produce food in the form of glucose. Oxygen is also produced as waste. I am going to investigate the factors that affect the rate of photosynthesis. The factor I have chosen to investigate is light intensity. Does varying degrees of light intensity affect the rate of photosynthesis in a green plant. Canadian pondweed (Elodea) will be used for this experiment, as when placed in water it gives of bubbles of oxygen from the cut end. This factor makes it ideal for observing the amount of oxygen given off when placed under varied light intensities. Aim The aim of this experiment is to determine whether the intensity of light affects the rate of photosynthesis in plants. Background Knowledge Photosynthesis occurs only in the presence of light. It is a chemical process used to turn inorganic compounds, carbon dioxide and water into organic compounds, carbohydrates. Photosynthesis occurs in chloroplasts, which are tiny membrane-bound bodies containing the light-trapping pigment chlorophyll. The equation for photosynthesis is: Stephanie Ellis Aby Chlorophyll Carbon dioxide + Water > Sunlight > Glucose + Oxygen Chlorophyll 6CO2 + 6H2O > Sunlight > C6H12O6 + 6O2 There have been many experiments proving that all plants need light in order to photosynthesise. The reason that light intensity does effect the rate of photosynthesis is because as light falls on the chloroplasts in a ...read more.

Middle

Varying the distance the lamp is from the beaker changes the light intensity, this happens because, the further a beam of light travels, the wider the beam becomes, when the beam hits a surface the light is spread over the surface, but if the surface was closer the beam would not be as wide and therefore more intense. Next I cut the bottom of the stem of the Elodea and placed in to the water upside down. I left the Elodea for one minute before I started to time the amount of oxygen bubble in the three minutes. I did this because as I am using the same piece of Elodea for each experiment, therefore I can make sure that photosynthesis was not taking place. After the one minute, I started the stopwatch and counted the amount of oxygen bubbles released by the plant. I recorded my results on my result table. I then changed the water and repeated the experiment measuring the lamp 4cms away. Next I repeated the experiment with the lamp 6cms away, then 8cm away, and final 10cms away. When I looked at my results I notices an anomalous result for 6cms distance, therefore I repeated this distance. Results table Distance away from Elodea (cms) Frequency of oxygen bubbles (in 3 min period) ...read more.

Conclusion

The retest experiment produced 39 oxygen bubble following the pattern that I predicted, and the pattern other experiments. The anomalous result has been added in my graph. If I were to do this experiment again I would change my method using a measuring cylinder as described above. My experiment is more than adequate to use in schools, with limited equipment. But the amount of errors in my method was not reliable enough for top scientist to use. This is because of the high level of errors which where beyond my control. A top scientist would have the equipment need to produce an experiment to the highest degree of accuracy. To extend this investigation further I would change the variables for example the type of plant I was using. I would try different types of plant and see if the results are similar for each type of plant. Also I could investigate the rate of photosynthesis when I changed the in take of Carbon dioxide or change the temperature. If I was to change the variable of my experiment. Eg. Temperature. I would still more or less follow my method, only using a hot water bath and a thermometer to record the temperature and the number of oxygen bubbles produced. I would record the number of oxygen bubbles given off at 20oC, 30oC, 40oC, 50Oc and 60oC. If I decide to investigate this variable I predict that as the temperature increased the cells would be killed therefore decreasing the rate of photosynthesis. ...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

    An investigation into the effect of light intensity on the rate of photosynthesis of ...

    5 star(s)

    bubbles, it is quite hard for someone to concentrate on counting fast moving bubbles for a long period of time. So in the main experiment, I will try to make the distance between 10cm and 30cm. This will give me accurate results and also the bubbles will not be produced very fast.

  2. Marked by a teacher

    Investigating Factors Affecting the Rate of Photosynthesis.

    5 star(s)

    This should boil the ethanol) * When all the chlorophyll (green colour) is removed and the cuticle is broken down, take the leaf out and dry on white board. * Put iodine on leaf * Where there is starch produced by photosynthesis, it will turn blue/black but if there's no starch, it will just stay white.

  1. Marked by a teacher

    Factors That Affect the Rate of Photosynthesis

    3 star(s)

    (For example: For a distance of 5mm, we will begin taking results when the plant starts photosynthesizing, therefore it'll have bubbles coming out of the stem at constant speed. We will take this for one minute then take restart and repeat this procedure two more times).

  2. Investigating the effect of temperature on the rate of photosynthesis

    Discussion By looking at the class average graph and our group graph they both follow the same trend. On graph 1 (group average) the curve increases rapidly from 0oC to around 22oC, where the average rate of oxygen released rises from 0.6mm3/min to 12mm3/min.

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

    * Water availability - Water is essential in photosynthesis to keep the stomata open. If there is not enough water, the stomata will close up, depriving the plant of the carbon dioxide it needs for photosynthesis. Water is involved in photolysis, therefore the more water there is, the greater the amount of hydrogen ions produced from the photolysis of water.

  2. Three separate experiments which are to be carried out to investigate a plant's unique ...

    This again is essential. I would say that the experiment is accurate and efficient, but only the set up instructions are followed accurately. The set up has to be 100% correct to obtain accurate results. When the stopwatch is started, and the two minute mark comes up (every 2 minutes being the time when a reading has to be taken)

  1. Investigate the factors, which affect photosynthesis.

    This means when the leaves change and adapt to their surrounding such as climate, etc. Evergreen plant has chlorophyll present in it. Chlorophyll is a green substance, which contains chloroplasts and makes the leaves green. Chlorophyll is important for photosynthesis. Magnesium is a green element, which is found in chlorophyll.

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

    There was enough evidence to draw a suitable conclusion. The equipment used was more reliable than counting bubbles but there were still inaccuracies in the experiment. Sometimes the air given off from the elodea, did not go into the funnel and is not recorded in the experiment.

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