The Affects of Light Intensity on the Rate of Photosynthesis

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The Affects of Light Intensity on the Rate of Photosynthesis

Variables:

  1. Independent: light intensity
  2. Dependent: the rate of photosynthesis, and the number of oxygen bubbles produced.
  3. Controlled:
  • The same type of plant must be used.
  • The time in which the oxygen bubbles are counted must be the same (five minutes, measured using a stopwatch).
  • The time taken for the plant to adapt in its new environment must be kept the same (two minutes measured with a stopwatch).

Apparatus:

  • A Green plant
  • A Test tube
  • Some Water
  • Stop-watch
  •  A pair Scissors
  • Table of results
  • Two lamps

Method:

  1. Gather the apparatus listed above.
  2. Cut the plant from both ends using the pair of scissors.
  3. Fill the test tube with water, and put the plant in the tube.
  4. Make sure that the plant, which was put in the test tube fully, sinks in the water.
  5. You need to wait two minutes before you can start counting the oxygen bubbles.
  6. Make sure that you use the same plant for every experiment.
  7. Make sure that the temperature is the same, for accurate readings.
  8. As soon as the two minutes is over, you start the oxygen bubbles.
  9. After the second five minutes are over, turn on of the lamps on, and wait for wait another two minutes. And when the two minutes are over start the count again.
  10. Redo the whole experiment again with tow lamps. And make sure you keep the temperature and plant the same.
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Data Collection:

Table showing the number of oxygen bubbles produced when certain numbers of lamps are turned on

Data Processing and Presentation:

Conclusion:

With a greater light intensity the rate of photosynthesis increases, because with more light there are more photons which are taken in by the plant leaves. This will increase the rate at which light dependent phase takes place. In the light dependent phase, the photosynthetic organism converts the light energy (photon) into energy carried by electrons. In photosynthesis the ...

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There are a few grammatical and spelling errors that should have been picked up during the reviewing process as, reviewing what you have written before you hand it in is essential for any piece of coursework. The technical terms used are basic in places and good in others, proving that the student has the potential to fulfil the expectations at this level.

The student should had started with a hypothesis as this would have helped them later on in the essay, this only need to be a sentence max about what you think is going to happen in the experiment. The student has identified which are the independent and dependant variables in this experiment and which are the other variables that need to be controlled; this is a good skill to have as throughout scientific education you are expected to do this. To make this section better the student could have said why the other variables needed to be controlled and how they were going to be controlled. The apparatus list is basic, stating what is needed and not why it is needed, this is a skill that will prove to examiners that you have a higher level of understanding about the experiment you are carrying out; phrases such as ‘Some Water’ should not be used instead say water or state a volume of water that you will be using as ‘some water’ is not scientifically correct. The conclusion is good explaining the concepts behind the results. The evaluation is also basic using words such as ‘tricky’ instead use words such as difficult as tricky as it does not show the examiner that you have good understanding of what is required for a experiment write up. All of the advice I have given I would not have known at GCSE it is only from doing about one write up a week for As Biology that I have gained all of the skills so do not worry about not doing them this time just remember them for next time!

The response could have been more explicit for example, a hypothesis could have been stated at the beginning as this would had given the student more to talk about when it came to the conclusions and evaluation sections. The question set has been answered and the appropriate evidence e.g. method has been given to support the answer