• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9

How light intensity affects the rate of photosynthesis.

Extracts from this document...

Introduction

HOW LIGHT INTENSITY AFFECTS THE RATE OF PHOTOSYNTHESIS. Photosynthesis is the process in which plants make their own food using light. To make the food they also require Carbon Dioxide, Chlorophyll and water. This can be shown in an equation: Carbon + Water light Glucose + Oxygen. Dioxide Chlorophyll The balanced word equation for this is: 6CO2 + 6H2O C6H12O6 + 6O2 The plant takes in light energy from the sun, using the palisade cells, which are situated in the leaf. The cells contain Chlorophyll, which is the green substance inside the leaf, and also chloroplasts, which trap the sun's energy. This then reacts with the water. The plant uses light energy to separate 1 hydrogen atom from the water. This gives the OH - ion, which is hydroxyl, and the H+ ion that is hydrogen. These are then unsatisfied bonds so they join together to form 2 water molecules, 1 oxygen and 4 hydrogen molecules. (The hydrogen ions are turned into glucose), this means that the more light there is, the more water is split and hence there is more oxygen. This is all part of the light stage. The light stage involves this splitting of water and also the production of ATP, this is a source of energy which is later used in the dark stage. The light stage traps the sunlight and converts it into chemical energy. Oxygen produced in the light stage is evolved as oxygen gas, and the hydrogen reduces the carbon dioxide to carbohydrate. ...read more.

Middle

Add a spatula of sodium hydrogen carbonate to the boiling tube. 3) Place the beaker on 0cm, switch the lamp on and wait until tiny bubbles appear. When this occurs begin timing the experiment for 1 minute, record your results. 4) Move the beaker to 5cm and repeat the experiment. Keep moving the beaker up 5 cm each time. Use the stirring rod to stir the water in the beaker throughout the experiment so that the heat is evenly spread. 5) When you have a full table of results, repeat the whole experiment again so that your experiment is more accurate and work out the average. To make sure my experiment is a fair test I will keep certain things the same, I will do the experiment twice to make sure it is accurate, I will only have 1 variable throughout the experiment, this will be the distance of the light source. The temperature will be approximately 23 degrees (room temp.) because more oxygen will be produced. I will use the same piece of pondweed, the same lamp and the same amount of water each time. I will be changing the light intensity in my experiment, as this is what my investigation is based on. I will do this by moving the pondweed further away each time. In my investigation I will measure how many bubbles of oxygen are given off in one minute. ...read more.

Conclusion

As the plant bubbled very quickly near the start, it is possible that I did not manage to count all of the bubbles or I could have miscounted. These could all cause 1 result to be out. I could make my experiment better by making sure I used the same piece of pondweed each time, the same size, the same light - incase the 1 bulb was stronger than the other, the same amount of water each time. I could also repeat my experiment a few more times using different lengths to get more results and hence a more accurate graph. I think my experiment was good enough to give the conclusion that light intensity affects the rate of photosynthesis because my experiment was as fair as possible and I didn't make many errors. My graph also proves this because it is a curved line, which shows the light intensity, and rate of photosynthesis are proportional to one another. There are some other experiments I could carry out to extend my investigation such as, investigating the other limiting factors (carbon dioxide concentration and temperature) which affect photosynthesis rate. I could also extend the light intensity experiment by using different types of lights such as fluorescent or halogen lights. I could also investigate how different coloured pigments absorb the light more, for example black absorbs light and white reflects it, and chlorophyll is a green substance so maybe a green pigment would affect 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. What is the effect on the rate of respiration of yeast cells with glucose ...

    The precision and reliability of the results is shown by length of the error bars. Long error bars indicate a great range within the results, which corresponds to a large uncertainty, or error within the results making them unreliable. Shorter error bars indicate a small range within the results, which

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

    but also less transpiration would occur and so plants would not have to be as adapted to water shortage and would not have to have xerophytic adaptations to survive there. Zones 5 and 8 saw a decrease in SDI. This could be because parallel to these two zones were two trees growing.

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

    The sum of the figures calculated in steps 3 and 4 = 1.360749506 x 10-3 + 2.120994181= 2.122354931. 6. The square root of the figure calculated in step 5 = 1.45683044. 7. The difference between the two means (step 2)

  2. The investigation is aiming to look at transpiration.

    and accurate as this would give me a better range and average to work with. EVALUATION The experiment was useful in testing my hypothesis. The results prove that my predictions were correct. there were not many sources of error, the little involved are listed below: The type of plant used

  1. An experiment to see how light intensity affects the photosynthesis of a plant.

    by the plant won't be sufficient enough for it to become the limiting factor. If my experiment were to be drawn out over a long period of time, then I would need to add something like sodium hydrogen carbonate to the water so that there would be a large enough supply of carbon dioxide.

  2. An Investigation to find out how Light Intensity affects Photosynthesis in Pondweed.

    I shall maintain this by simply using the same piece of pondweed for each set of results. This may however cause the pondweed to slightly loose it's efficiency at photosynthesis. Though this inaccuracy would be lesser than that caused by using different pieces of pondweed for each set of results,

  1. How temperature affects the rate of photosynthesis.

    The light independent reactions of photosynthesis: This stage is known as the Calvin cycle or the Dark stage as light is not required here and it takes place in the stoma region of the chloroplast. Carbon dioxide from the atmosphere is the raw material required to carry out these reactions.

  2. INVESTIGATING HOW TEMPERATURE AFFECTS THE

    I have decided to carry out the investigation this way so that I can get the required temperature the most quickly (from room temp) so I do not have to wait too long. For the temperatures above room temperature i.e.

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