Investigate the way light affects the rate of photosynthesis on Elodea.

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Photosynthesis

Aim: To investigate the way light affects the rate of photosynthesis on Elodea.

Equipment: Test tube, Test tube rack, Lamp, Ruler, Thermometer,

Other: Water, Sodium bicarbonate, pond weed.


Plan of task: A piece of pondweed will be cut and placed into a beaker containing water and sodium hydrogen carbonate. A lamp will be shined on to the pondweed and the amount of bubbles released from the plant will be counted. The lamp will be adjusted to different distances from the plant to get different results.
Light intensity is to be the variable explored in this investigation. Increasing or decreasing the distance from the light source to the plant can vary light intensity. Light Wavelength Light energy is absorbed by pigments in the leaf such as chlorophyll.

Factors of experiment: I must use the right type of light, Blue light is easily absorbed by chlorophyll, this is the type of light which comes from sun.

The time when bubbles are counted must always be the same (Five minutes)

The water temperature must be kept at 20?C.

There must be the same amount of water in the tube each time.

Add the same amount of Sodium bicarbonate in to the pond weed and water each time. The experiment must be carried out in the space of two hours so the plants don't use up a significant percentage of oxygen.

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These factors must all be kept constant otherwise each time the experiment is carried out the results will change, then the experiment would be biased.

The pond weed must stay the same.

The results would be more accurate if the factors were replaced (the same) each time.

Prediction: I predict that increasing the light intensity will increase the rate of photosynthesis because the light intensity is much greater when the light is closer to the plant I think this because in the summer when the light intensity is greater, plants and flowers grow larger and have many different fruits and ...

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