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

Investigating the affect light intensity has on photosynthesis

Extracts from this document...


Biology Coursework Investigating the affect light intensity has on photosynthesis Plan All living organisms need food. They need it as a source of raw materials to build new cells and tissues as they grow. They also need food as a source of energy. Food is a 'fuel', which drives essential living processes and brings about chemical changes. Animals take in food, digest it, and use the products to build their tissues or to produce energy, but plants, apart from a few insect-eating species, do not appear to take in food. This is because plants find food sources in water and the air. This is known as photosynthesis. Chlorophyll is a green substance found in the chloroplasts of plant cells. It absorbs sunlight and makes the energy from sunlight available for chemical reactions. Thus, chlorophyll converts light energy to chemical energy. Therefore photosynthesis is the building-up of food compounds from carbon dioxide and water by green plants using energy from sunlight, which is absorbed by chlorophyll. The products of photosynthesis are glucose and oxygen. There are many factors, which affect the rate of photosynthesis, including light intensity, temperature and carbon dioxide concentration. The maximum rate of photosynthesis will be constrained by a limiting factor. ...read more.


Preliminary I completed a preliminary investigation to test my basic idea and equipment. I placed the pondweed 5cm away from the lamp. At first no bubbles were given off and so I decided to increase the temperature of the water from around 17�C to 25�C. The pondweed started to give off bubbles and I collected 17 in a minute. I then moved the lamp 10cm away from the equipment and collected 9 bubbles in a minute. After completing my preliminary investigations I decided that the water I use in my experiments should be at 25�C to encourage photosynthesis. Therefore all the water I use must be at 25�C to ensure a fair test. I didn't experience any other problems with the equipment used in my preliminary investigation and so I decided I was ready to begin my experiments. Practical - Obtaining my evidence Aim: To discover what effect light intensity has on the rate of photosynthesis. Apparatus: Canadian pondweed, funnel, supports, a test tube, a beaker, water at 25�C, a lamp, a ruler and a bung. Method: 1) Fill a beaker with 700cm� of water at a temperature of 25�C. 2) Cut the Canadian pondweed into a 3cm segment. 3) Fill a test tube with water (also at 25�C) ...read more.


Firstly, the distance between the lamp and the Canadian pondweed was not measured to a high degree of accuracy. Ideally the distance should have been measured from the filament of the light bulb to the centre of the plant but this was not possible. Another inaccuracy was in the time keeping as there was often a small difference in when I began timing the minute, e.g. after the first bubble had been released or just before. Overall even though my experiment was open to some inaccuracies I believe it was accurate enough to support my predictions. To improve my results I could simply increase the length of time I measure the number of bubbles released to 5minutes although I would have to ensure that the water remained at the same temperature throughout. One way of doing this would be to place a Perspex block between the lamp and the plant, which would absorb most of the heat, while allowing the light energy to pass through. Another way of increasing the reliability of my results would be to take more readings. I would like to extend my investigations into light intensity and photosynthesis by investigating which colour of the spectrum produces the highest rate of photosynthesis and what effect halogen and fluorescent lights have on the rate of photosynthesis. Sources: G.C.S.E. Biology - D.G. Mackean Biology - Mary Jones & Geoff Jones ...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)

    it didn't reach that certain level where an increasing of light intensity will not affect the rate of photosynthesis any more. This is because the light source is not bright enough. Even when the light intensity is 5, it is still a limiting factor. So the graph didn't level off.

  2. Marked by a teacher

    Investigate the relationship between wavelength of light and the rate of photosynthesis using pondweed.

    3 star(s)

    Analysis The bar chart represents results collected in the second experiment because these were more accurate than the first lot. I discovered that the white light produced the most bubbles on both experiments. The white light carried photosynthesis out at the fastest rate, producing the greatest amount of oxygen bubbles.

  1. Marked by a teacher

    Factors That Affect the Rate of Photosynthesis

    3 star(s)

    point because it'll be the carbon dioxide level or temperature that is preventing the rate of photosynthesis. A plant relies mainly on carbon dioxide, temperature and light intensity. We have already provided the plant light intensity but not carbon dioxide and temperature.

  2. How does light intensity affect the rate of photosynthesis

    * Sodium Hydrogen Carbonate (NaHCO ) * Thermometer (if necessary) * Small knife * Water Guillaume Wright 10C2 GCSE Science Coursework C/W Collecting Oxygen gas during Photosynthesis - How does light intensity 29/4/01 affect the rate of photosynthesis Diagram: Measuring cylinder Stopwatch Syringe Delivery tube Clamp Stand Oxygen bubble

  1. Investigate the affect of light colour (wavelength) on photosynthesis.

    Although they are consistent I do not think they are accurate. In the prediction it says that blue would be the most absorbed as it has the most energy to produce more oxygen. But as seen in the graph and results table, it has one of the lowest bubble rate counts.

  2. Investigate the factors, which affect photosynthesis.

    * Potassium hydroxide and sodium hydrogen carbonate are alkaline, therefore can burn and are corrosive. * No eating or drinks should be brought in the lab. * Ties should be tucked in and all lose clothes also should be tucked in.

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

    This means that we are at least 95% confident that the mean volume of oxygen released at 35oC and 65oC differs. T- test for 0oC and 65oC 1. Mean volume of oxygen released at OoC = 0.1830769231. Mean volume of oxygen released at 65oC = 4.929230769.

  2. Investigate the effect of light intensity on the rate of photosynthesis in an aquatic ...

    This meant that our investigation was difficult to start, as the pond weed was finding the conditions we were working under inadequate for photosynthesis, whereas other groups were finding the investigation much easier to conduct. Another aspect of my method which was faulted by the fact that the experiment took

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