• 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

# How light intensity affects the rate of photosynthesis

Extracts from this document...

Introduction

How light intensity affects the rate of photosynthesis The aim of my experiment was to determine whether intensity of light would affect the rate of photosynthesis in a plant. To do this, I placed a piece of elodea in varying light intensities, and observed the amount of oxygen being given off. I used elodea because it gives off bubbles from a cut end of a stem. Plan Photosynthesis occurs only in the presence of light, and takes place in the chloroplasts of green plant cells. Photosynthesis is the production of sugar from carbon dioxide and water causing the release of sugar and oxygen. It is a chemical reaction and the chemical equation for it can be written as: Carbon Dioxide + Water ==> Glucose + Oxygen 6CO2 + 6H2O ==> C6H12O6 + 6O2 The chloroplasts in the cells take in the Carbon Dioxide and water and by using sunlight, convert it into glucose and oxygen. The oxygen is released through tiny holes in the bottom of the leaf called stomatas. There are three factors that limit the rate of photosynthesis. These three factors are: * Carbon Dioxide - The more carbon dioxide there is for the plant, the higher the rate of photosynthesis. There can be an unlimited amount of carbon dioxide and the plant will only use what it needs. ...read more.

Middle

Variable I shall keep the same Variables I will change Variables I will measure Throughout the whole experiment, I will use the same piece of elodea, water and Potassium Hydrogen Carbonate and the temperature. Should the water have to be changed due to temperature rise, then the exact same amount of KHCO3 will be used to make sure that extra CO2 is not let off. The distance between the elodea and the lamp will change throughout the experiment to give us the results. I will measure the number of bubbles that appear from the stem of the elodea. This will not be very exact but most of the bubbles are the same size so it will not change the results much. To make this a fair test I will make all the above precautions and make sure that all measurements are recorded with accuracy and care. The amount of CO2 would be hard to measure because we do not know how much is actually being released per bubble. It may be a big bubble and still be counted as "1" bubble. It will be difficult to control how much light the elodea is getting. In the room in which we did these tests, the main lights were on and so that may change our results to a higher rate of photosynthesis. ...read more.

Conclusion

My results matched my prediction and secondary data source. I am happy with the results that we gathered for this investigation. Evaluation My results were accurate enough to make a firm conclusion. This was because I had completed 3 tests for each measurement and taken an average. There are slight things which may have changed the results but these are only minor problems: * The size of the bubbles - these could vary between big and small and no matter what size they were, they were still counted as "one bubble!". To get over this problem, you would have to use a syringe to take in all the CO2 and measure the volume in cm�. * The light in the room - could have sped up the rate of photosynthesis and made our results slightly faulty. To overcome this problem, the experiment should have no background light, just a desk lamp. * Miscounting bubbles - due to human error. This could be overcome by using a syringe to take in all the bubbles, or use a computer to count the bubbles. These could all be changed and improved to make the perfect environment to complete this test in. The results we gathered were that of a fair test. All our recorded measurements came from a single piece of elodea. This test all ran smoothly and there were no unexpected results and no mistakes were made during the test. ...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

# Related GCSE Green Plants as Organisms essays

1. ## An Investigation into the Effects that Different Light Intensities have on the Speed of ...

5 star(s)

until the experiment was completely ready to be carried out and that it was switched off as soon as the experiment was finished. I, perhaps, was not as disciplined with this as I should have been. Although my results do show a linear regression, they also could show more of a curve if the linear regression line was removed.

2. ## Confirm which factors increases or decreases the rate of photosynthesis.

Safety Precautions While conducting this experiment many harmful substances and dangerous equipment were used. Therefore safety precautions were taken place. Below are the safety precautions: * All beakers and test tubes should be kept of the edges. * Long hair should always be tied at the back so that it does not come in the way during the experiment.

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

Temperature has a large effect on the functioning of enzymes. There are two different explanations for the functioning of enzymes, one simple and one slightly more complex. The more simple of the two is the 'lock and key' hypothesis. An enzyme is a globular protein, coiled into a precise 3D shape.

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

This was when the distance from plant to light source was 0 cm or only 5 cm. A large factor in determining data accuracy is the amount of human error during experiments. The rate at which oxygen bubbles were being produced by my plant was so high that I found it difficult to count the amount of bubbles.

1. ## Investigating the effect of Light Intensity on Elodea.

The length needs to be the same in each experiment so that light intensity is the only variable. Length of Elodea used in preliminary exp. - 20cm. * Cut the ends of the pondweed so that the opening is fresh, not dying away (as done with flowers).

2. ## INVESTIGATING HOW TEMPERATURE AFFECTS THE

get a fair and more precise time for each, instead of relying on a watch or clock. Distilled water I will use distilled Water, as this will ensure a more accurate result as normal tap water has chemicals added which can affect the experiment.

1. ## How temperature affects the rate of photosynthesis.

Light energy drives the light dependant reactions and the products formed at the end of it account for the functioning of the light independent reactions. Light energy is trapped from the source like the sun, by two types of photosynthetic pigments: Pigment Colour Chlorophylls Chlorophyll a Yellow-green Chlorophyll b Blue-green Carotenoids B carotene Orange Xanthophyll Yellow 1.

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

Average /lux 0 3.44 1.72 3.28 2.80 1 3.20 2.32 2.42 2.60 2 2.66 1.46 2.88 2.40 3 2.32 2.28 3.20 2.60 4 2.08 2.66 2.00 2.30 5 1.76 1.82 1.78 1.80 6 1.70 0.40 1.40 1.20 7 1.20 0.40 1.36 1.00 8 1.06 0.34 1.28 0.90 9 0.90 0.30

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